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10-K

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UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 10-K

For the Fiscal Year Ended December 31, 2025

Commission File Number 001-35456

ALLISON TRANSMISSION HOLDINGS, INC.

(Exact name of registrant as specified in its charter)

One Allison Way

Indianapolis, IN46222

(Address of principal executive offices and zip code)

(317) 242-5000

(Registrant’s telephone number, including area code)

Securities registered pursuant to Section 12(b) of the Act:

Title of Each Class Trading Symbol(s) Name of Each Exchange On Which Registered

Common Stock, $0.01 par value ALSN New York Stock Exchange

Securities registered pursuant to Section 12(g) of the Act: None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ☒ No ☐

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes ☐ No ☒

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☒ No ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act. ☐

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report.☒

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements. ☐

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b). ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Exchange Act). Yes ☐ No☒

The aggregate market value of the voting and non-voting stock held by non-affiliates was approximately $7,896 million as of June 30, 2025.

As of January 30, 2026, there were 82,805,592 shares of Common Stock outstanding.

Documents Incorporated by Reference

Portions of the Registrant’s definitive Proxy Statement for its 2026 annual meeting of stockholders will be incorporated by reference in Part III of this Annual Report on Form 10-K.

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Page

PART I.

Item 1. Business 4

Item 1A. Risk Factors 18

Item 1B. Unresolved Staff Comments 35

Item 1C. Cybersecurity 35

Item 2. Properties 38

Item 3. Legal Proceedings 38

Item 4. Mine Safety Disclosures 38

PART II.

Item 6. [Reserved] 40

Item 7A. Quantitative and Qualitative Disclosures About Market Risk 56

Item 8. Financial Statements and Supplementary Data 57

Item 9A. Controls and Procedures 102

Item 9B. Other Information 103

Item 9C. Disclosure Regarding Foreign Jurisdictions that Prevent Inspections 103

PART III.

Item 10. Directors, Executive Officers and Corporate Governance 104

Item 11. Executive Compensation 104

Item 14. Principal Accountant Fees and Services 105

PART IV.

Item 15. Exhibits and Financial Statement Schedules 106

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Cautionary Note Regarding Forward-Looking Statements

This Annual Report on Form 10-K contains forward-looking statements. The words “believe,” “expect,” “anticipate,” “intend,” “estimate” and other expressions that are predictions of or indicate future events and trends and that do not relate to historical matters identify forward-looking statements. You should not place undue reliance on these forward-looking statements. Although forward-looking statements reflect management’s good faith beliefs, reliance should not be placed on forward-looking statements because they involve known and unknown risks, uncertainties and other factors, which may cause actual results, performance or achievements to differ materially from anticipated future results, performance or achievements expressed or implied by such forward-looking statements. Forward-looking statements speak only as of the date the statements are made. We undertake no obligation to publicly update or revise any forward-looking statement, whether as a result of new information, future events, changed circumstances or otherwise. These forward-looking statements are subject to numerous risks and uncertainties, including, but not limited to: the significant costs we are expected to incur in connection with the integration of the Off-Highway Drive & Motion Systems business (the “Acquired Off-Highway Business”) of Dana Incorporated ("Dana"); our ability to successfully integrate the Acquired Off-Highway Business and its operations in the expected time frame; our ability to realize all of the anticipated benefits from the integration of the Acquired Off-Highway Business and its operations and to effectively manage our expanded operations; our participation in markets that are competitive; our ability to prepare for, respond to and successfully achieve our objectives relating to technological and market developments, competitive threats and changing customer needs, including with respect to electric hybrid and fully electric commercial vehicles; increases in cost, disruption of supply or shortage of labor, freight, raw materials, energy or components used to manufacture or transport our products or those of our customers or suppliers, including as a result of geopolitical risks, natural disasters, extreme weather events, wars and public health crises such as pandemics; global economic volatility; general economic and industry conditions, including the risk of prolonged inflation and recession; labor strikes, work stoppages or similar labor disputes, which could significantly disrupt our operations or those of our principal customers or suppliers; the highly cyclical industries in which certain of our end users operate; uncertainty in the global regulatory and business environments in which we operate; the concentration of our net sales in our top five customers and the loss of any one of these; cybersecurity risks to our operational systems, security systems or infrastructure owned by us or our third-party vendors and suppliers; the failure of markets outside North America to increase adoption of fully automatic transmissions; the success of our research and development efforts, the outcome of which is uncertain; U.S. and foreign defense spending; risks associated with our international operations, including acts of war and increased trade protectionism and tariffs; the discovery of defects in our products, resulting in delays in new model launches, recall campaigns and/or increased warranty costs and reduction in future sales or damage to our brand and reputation; our ability to identify, consummate and effectively integrate acquisitions and collaborations; and risks related to our indebtedness.

Important factors that could cause actual results to differ materially from our expectations are disclosed under Part I, Item 1A., “Risk Factors” in this Annual Report on Form 10-K. All written and oral forward-looking statements attributable to us, or persons acting on our behalf, are expressly qualified in their entirety by these cautionary statements as well as other cautionary statements that are made from time to time in our other United States Securities and Exchange Commission ("SEC") filings or public communications. You should evaluate all forward-looking statements made in this Annual Report on Form 10-K in the context of these risks and uncertainties.

Certain Trademarks

This Annual Report on Form 10-K includes trademarks, such as Allison Transmission, eGen Flex, eGen Power, FracTran, ReTran and Walker Die Casting, which are protected under applicable intellectual property laws and are our property and/or the property of our subsidiaries. This report also contains trademarks, service marks, copyrights and trade names of other companies, which are the property of their respective owners. We do not intend our use or display of other companies’ trademarks, service marks, copyrights or trade names to imply a relationship with, or endorsement or sponsorship of us by, any other companies. Solely for convenience, our trademarks and trade names referred to in this report may appear without the ® or TM symbols, but such references are not intended to indicate, in any way, that we will not assert, to the fullest extent under applicable law, our rights or the rights of the applicable licensor to these trademarks and trade names.

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PART I.

ITEM 1. Business

Overview

Allison Transmission Holdings, Inc. and its subsidiaries (“Allison,” “we,” “us” or “our”) is a global leader in high-performance mobility and work solutions built for the needs of the modern industrial world. The business was founded in 1915 and has been headquartered in Indianapolis, Indiana since inception. Allison is traded on the New York Stock Exchange under the symbol “ALSN”.

We have a global presence by serving customers in North America, Asia, Europe, South America, and Africa, with approximately 76% of our revenues being generated in North America in 2025. We serve customers through an independent network of approximately 1,500 independent distributor and dealer locations worldwide as of December 31, 2025.

On January 1, 2026, we completed the acquisition of the Acquired Off-Highway Business, expanding our portfolio of drivetrain and propulsion solutions and broadening our participation in off-highway end markets. As a result of this acquisition, we now operate a broader range of technologies and products and serve a more diverse global customer base across on-highway, off-highway, and defense applications.

Unless otherwise expressly provided herein, the information disclosed in this Part I, Item 1 is provided as of and/or for the year ended December 31, 2025 and, accordingly, does not give effect to the acquisition of the Acquired Off-Highway Business.

Our Business

We are the world’s largest manufacturer of fully automatic transmissions for medium- and heavy-duty commercial vehicles and medium- and heavy-tactical U.S. defense vehicles, and subsequent to the acquisition of the Acquired Off-Highway Business, a leading provider of drivetrain and propulsion solutions for off-highway applications. Allison products are used in a wide variety of applications, including on-highway vehicles (distribution, refuse, construction, fire and emergency), buses (primarily school, transit and coach), motorhomes, off-highway vehicles and equipment (energy, mining, construction and agriculture) and defense vehicles (tactical wheeled and tracked). We believe the Allison brand is one of the most recognized in our industry as a result of the performance, reliability and fuel efficiency of our propulsion solutions and is associated with high quality, durability, vocational value, technological leadership and superior customer service.

We introduced the world’s first fully automatic transmission for commercial vehicles over 75 years ago. Since that time, we have driven the trend in North America and other parts of the world towards increasing automaticity by targeting a diverse range of commercial vehicle vocations. Allison products are optimized for the unique performance requirements of end users, which typically vary by vocation. Our products are highly engineered, requiring advanced manufacturing processes, and employ complex software algorithms for our propulsion system controls to maximize end user performance.

As a result of our acquisition of the Acquired Off-Highway Business, we now offer an expanded portfolio of drivetrain, motion and propulsion solutions, providing complementary product breadth and an enhanced ability to support customers across multiple end markets. The Acquired Off-Highway Business has historically served end markets with demand characteristics that differ from our traditional on-highway markets, contributing to a more diversified portfolio.

Following our acquisition of the Acquired Off-Highway Business, we continue to operate under the Allison name, but our operations are now comprised of two business units: Allison Transmission and Allison Off-Highway

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Drive & Motion Systems. Business unit leadership is located globally, reflecting the international nature of our operations and the importance of local market insights, sourcing, production and customer support.

Our Industry

Commercial vehicles typically employ one of three transmission types: manual, automated manual or fully automatic. Manual transmissions and automated manual transmissions ("AMT") are the most prevalent transmission types used in Class 8 tractors in North America. Manual transmissions are the most prevalent in medium- and heavy-duty commercial vehicles, generally, outside North America. Manual transmissions utilize a disconnect clutch causing power to be interrupted during each gear shift resulting in energy loss-related inefficiencies and less work being accomplished for a given amount of fuel consumed. In long-distance trucking, this power interruption is not a significant factor, as the manual transmission provides its highest degree of fuel economy during steady-state cruising. However, steady-state cruising is only one part of the duty cycle. When the duty cycle requires a high degree of “start and stop” activity or speed transients, as is common in many vocations as well as in urban environments, we believe manual transmissions result in reduced performance, lower fuel efficiency, lower average speed for a given amount of fuel consumed and inferior ride quality. Moreover, the clutches must be replaced regularly, resulting in increased maintenance expense and vehicle downtime. Manual transmissions also require a skilled driver to operate the disconnect clutch when launching the vehicle and shifting gears. AMTs are manual transmissions that feature automated operation of the disconnect clutch. Fully automatic transmissions utilize technology that smoothly shifts gears instead of a disconnect clutch, thereby delivering uninterrupted power to the wheels during gear shifts and requiring minimal driver input. These transmissions deliver superior acceleration, higher productivity, increased fuel efficiency, reduced operating costs, less driveline shock and smoother shifting relative to both manual transmissions and AMTs in vocations with a high degree of “start and stop” activity, as well as in urban environments.

Emerging technologies in commercial-duty propulsion solutions include electric hybrid and fully electric propulsion solutions in certain end markets and are in part driven by efforts to reduce fuel consumption, noise and greenhouse gas emissions. Fully electric powertrains differ from electric hybrid powertrains because they only have a battery for energy storage and exclusively power the wheels using electric motors. In contrast, electric hybrids may use multiple energy storage sources including diesel and hydrogen and may drive the wheels exclusively with electric motors or in parallel with an internal combustion engine. While both emerging technologies are gaining use in automotive markets and electric hybrids and fully electric propulsion solutions have gained use in the bus market, fully electric propulsion solutions remain in a developmental phase in the medium- and heavy-duty commercial vehicle market.

Our Served Markets

We sell our propulsion solutions globally for use in medium- and heavy-duty on-highway commercial vehicles, off-highway vehicles and equipment and defense vehicles. In addition to the sale of propulsion solutions, we also sell branded replacement parts, support equipment, aluminum die cast components and other products necessary to service the installed base of vehicles utilizing our solutions. The following table provides a summary of our business by end market for the fiscal year ended December 31, 2025.

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ON-HIGHWAY OFF-HIGHWAY

Refer to "Note 19. Concentration of Risk” of Notes to Consolidated Financial Statements included in Part II, Item 8., of this Annual Report on Form 10-K for additional information on our significant original equipment manufacturer (“OEM”) customers.

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North America On-Highway

We are the largest manufacturer of fully automatic transmissions for the on-highway medium- and heavy-duty commercial vehicle market in North America. The following is a summary of our on-highway net sales by vehicle class and type in North America for 2025.

Our North American on-highway market includes Class 4-5, Class 6-7 and Class 8 straight trucks and regional haul tractors, conventional transit, shuttle and coach buses, school buses and motorhomes. Class 8 trucks are subdivided into two markets: straight and tractor. Class 8 straight trucks are those with a unified body (e.g., refuse, construction, and dump trucks), while tractors have a vehicle chassis that is separable from the trailer they pull. Class 8 tractors are further divided into two subcategories: regional haul and line-haul. Regional haul tractors are typically used for local or regional hauling, whereas line-haul tractors are typically used in extended duration long distance hauling. We have been supplying transmissions for Class 8 straight trucks for decades, and it is a core end market for us. We have limited exposure to the Class 8 line-haul tractor market because lower priced manual transmissions and AMTs generally meet the needs of these vehicles, which are primarily used in long distance hauling.

We also provide electric hybrid propulsion solutions within the North American on-highway transit market, where interest in conserving fuel and reducing greenhouse gas emissions remains a customer desire. We compete primarily with BAE Systems plc in the transit market segment.

We sell substantially all of our propulsion solutions in the North American on-highway market to OEMs. These OEMs, in turn, install our propulsion solutions in vehicles in which our product is either the exclusive propulsion solution available or is specifically requested by end users. In 2025, OEM customers representing over 90% of our North American on-highway unit volume participated in long-term agreements (“LTAs”) with us. Generally, these LTAs offer the OEM customer defined levels of mutual commitment with respect to growing Allison’s presence in the OEMs’ products and promotional efforts, pricing and sharing of commodity cost risk. The length of our LTAs is typically between three and five years. We often compete in this market against (i) independent manufacturers of manual transmissions, AMTs and electric hybrid and fully electric propulsion solutions, (ii) fully automatic transmissions manufactured by Ford Motor Company (“Ford”), ZF Friedrichshafen AG (“ZF”) and Driventic GmbH (“Driventic”) and (iii) vertically integrated OEMs in certain weight classes that use their own internally manufactured transmissions in certain vehicles.

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Outside North America On-Highway

Outside North America we serve several different markets, including: Asia-Pacific, Europe, Middle East, Africa (collectively, “EMEA”), and South America.

We are a leading manufacturer of fully automatic transmissions for the medium-duty and heavy-duty commercial vehicle market outside of North America. We also provide fully electric propulsion solutions for the outside North America on-highway market. While the use of fully automatic transmissions in the medium- and heavy-duty commercial vehicle market has been widely accepted in North America, markets outside North America continue to be predominantly served by manual transmissions. Where adopted, fully automatic transmission-equipped medium- and heavy-duty commercial vehicles are concentrated in certain vocational end markets. We often compete in this market against (i) independent manufacturers of manual transmissions, AMTs and electric hybrid and fully electric propulsion solutions, (ii) fully automatic transmissions manufactured by ZF, Driventic, and Shaanxi Fast Gear Co., Ltd. and (iii) vertically integrated OEMs. The following is a summary of our on-highway net sales by region outside of North America for 2025.

Asia-Pacific. Our key Asia-Pacific markets include Australia, China, India, Japan and South Korea; however, we actively participate in several other important Asia-Pacific countries including Indonesia, Malaysia, Singapore, Taiwan and Thailand. In addition, OEMs in the Asia-Pacific market are increasingly exporting their products to other regions. Within Asia-Pacific, our sales efforts are principally focused on the transit bus, vocational truck, severe service, distribution and wide-body dump truck markets. Currently, manual transmissions are the predominant transmission type used in commercial vehicles in the Asia-Pacific region.

Europe, Middle East, Africa. EMEA is composed of several different markets, each of which differs from our core North American market by the degree of market maturity, sophistication and acceptance of fully automatic transmission and electric propulsion solution technology. Within Europe, we serve Western European developed markets, as well as Eastern European emerging markets, principally in the refuse, emergency, transit bus, coach bus, distribution, utility and wheeled defense vehicle markets. Competition in Western Europe is most notably characterized by a high level of vertical powertrain integration, with OEMs often utilizing vertically integrated manual transmissions and AMTs in their vehicles, and electric hybrid and fully electric propulsion solutions. The Middle East and Africa regions are generally characterized by very limited local vehicle production, with imports from China, Europe, India, South America, Turkey and the U.S. accounting for the majority of vehicles.

South America. The South American region is characterized by a high level of OEM vertical integration, with captive manual transmission and AMT manufacturing. Currently, manual transmissions are the predominant

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transmissions used in commercial vehicles in South America. We serve the South American region primarily in the bus, refuse, vocational truck and agricultural markets.

Global Off-Highway

North America. We have provided products used in vehicles and equipment that primarily serve energy, mining and construction applications in North America for over 75 years. Off-highway energy applications include hydraulic fracturing equipment, well-stimulation equipment, pumping equipment, and well-servicing rigs, which often use a fully automatic transmission in stationary pumping applications. We supply our heavy-duty off-highway transmissions to producers of well-stimulation and well-servicing equipment. Competition in this end market for 2025 included Caterpillar Inc. (“Caterpillar”), Twin Disc, Inc. (“Twin Disc”) and certain alternative hydraulic fracturing technologies.

We also provide heavy-duty transmissions used in mining trucks, specialty vehicles and construction vehicles. Off-highway mining and construction applications include trucks used to haul various commodities and other products around construction sites and mines, including underground mines. These trucks include rigid dump trucks, wide-body dump trucks and underground trucks with load capacities between 40 to 130 tons. Our major competitors in this end market for 2025 included vertically integrated companies that manufacture fully automatic transmissions for their vehicles. These vertically integrated competitors included Caterpillar, Komatsu Ltd. (“Komatsu”), and Volvo Group (“Volvo”). We also compete with independent manufacturers such as ZF. Specialty vehicles using our heavy-duty off-highway transmissions include airport rescue and firefighting vehicles. Our major competitor in this end market for 2025 was Twin Disc.

Outside North America. The following is a summary of our off-highway net sales by region outside of North America for 2025.

Asia-Pacific. Off-highway markets in Asia are shared by energy, mining and construction applications. Our primary competitors were Caterpillar, Danyang Winstar Auto Parts Co., Ltd., Twin Disc and manufacturers of electrified solutions in energy applications; Caterpillar, Xi’an FC Intelligence Transmission Co. Ltd. and Komatsu in mining applications; and Caterpillar, Volvo and ZF in construction applications in 2025.

Europe, Middle East, Africa. Our off-highway markets in EMEA are mining and construction. Our primary off-highway competitors for 2025 were Caterpillar, Volvo and Komatsu, all of which are vertically integrated manufacturers of off-highway mining vehicles, including the specific fully automatic transmission used in their mining

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trucks. A typical mining application is a rigid, underground or articulated dump truck, with competition from Caterpillar, Volvo and ZF in 2025.

As a result of the acquisition of the Acquired Off-Highway Business, we now provide drivetrain and motion solutions for a wide range of mobile and stationary off-highway equipment both in North America and outside North America. These solutions include optimized drivetrain systems, propulsion components and motion technologies designed for industries such as construction, agriculture, mining, material handling and other industrial applications. The portfolio encompasses systems that manage power conveyance to machines and power work functions, including axles, gearboxes, transmissions and related components, as well as motion systems tailored to customer performance and efficiency requirements across both conventional and electrified powertrains. Consequently, we now face competition in these expanded end markets.

Defense

We have had a long-standing relationship with the U.S. Department of Defense (the “DOD”) since the 1940s, when we began developing our first-generation tank transmission. Today, we sell substantially all of the propulsion solutions for medium- and heavy-tactical wheeled vehicles used by the U.S. military, including the Joint Light Tactical Vehicle, Stryker Armored Vehicle, the Family of Medium Tactical Vehicles, Heavy Expanded Mobility Tactical Trucks, Palletized Loading Systems, Heavy Dump Trucks and Heavy Equipment Transporters. Propulsion solutions for tactical wheeled vehicles are typically sold to OEMs.

We supply tracked vehicle propulsion solutions to the U.S. Army, including the Abrams M1A2 Main Battle Tank, Joint Assault Bridge, Assault Breacher Vehicles, M10 Booker and the M113A3 Armored Personnel Carrier family of vehicles. We also sell parts kits to the U.S. Army for Abrams Tank sustainment. See Part I, Item 1A., “Risk Factors” of this Annual Report on Form 10-K for a discussion of risks associated with our contracts with the DOD.

We have defense products in approximately 120 countries around the world as of December 31, 2025. Increasingly, we are supplying vehicle propulsion solutions for international tracked vehicles, such as light tracked personnel carriers, armored fighting vehicles, heavy tracked artillery systems, and Main Battle Tanks. Our defense products are manufactured at our headquarters in Indianapolis and by our licensees internationally for export world-wide.

Globally, we face competition primarily from QinetiQ Group plc, Renk AG/Renk America, SAPA S.p.A and ST Kinetics for the supply of tracked vehicle propulsion solutions. Additionally, we face competition from ZF in certain defense wheeled vehicles using automatic transmissions and from several AMT suppliers.

Service Parts, Support Equipment and Other

Our service parts, support equipment and other end market is comprised of: Allison-branded service parts and transmission fluids, aluminum die cast components, extended transmission coverage, remanufactured propulsion solutions, royalties, saleable engineering and support equipment. The aftermarket provides us with a relatively stable source of revenues as the installed base of vehicles and equipment utilizing our solutions continues to grow. The need for replacement parts is driven by normal vehicle and equipment maintenance requirements. Uninterrupted operation is generally critical for end users’ profitability.

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The sale of Allison-branded service parts and transmission fluids, remanufactured propulsion solutions and support equipment is fundamental to our brand promise. We have assembled a worldwide network of approximately 1,500 independent distributor and dealer locations as of December 31, 2025 to sell, service and support our solutions. As part of our brand strategy, our distributors and dealers are required to sell genuine Allison-branded service parts. Within the aftermarket, we offer remanufactured propulsion solutions as a cost-effective alternative for repairs and replacements. We also provide support equipment to our OEMs to assist in installing new Allison solutions into vehicles, and, therefore, sales of support equipment are dependent upon sales of new solutions. The competition for service parts and remanufactured propulsion solutions comes from a variety of smaller-scale companies sourcing non-genuine “will-fit” parts from unauthorized manufacturers. These “will-fit” parts often do not meet our product specifications, and therefore may be of lesser quality than genuine Allison parts.

Our Product Offerings

Allison transmissions and electric propulsion solutions are sold under the Allison Transmission brand name and remanufactured transmissions are sold under the ReTran brand name. The following is a summary of our product lines as of December 31, 2025.

On-Highway Products

Product Applications

eGen Flex Electric Hybrid Propulsion Solutions • Transit Bus

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Off-Highway Products

Product Applications

8000 Series • Hydraulic Fracturing Equipment• Rigid Dump Trucks

9000 Series • Hydraulic Fracturing Equipment• Rigid Dump Trucks

FracTran • Hydraulic Fracturing Equipment

Defense Products

Product Applications

X200 • Tracked Vehicles

3040MX • Tracked Vehicles

4040MX • Tracked Vehicles

X1100 • Tracked Vehicles

eGen Force • Tracked Vehicles

Subsequent to the acquisition of the Acquired Off-Highway Business, our product portfolio has expanded to include drivetrain and motion solutions for a wide range of mobile and stationary off-highway equipment. These solutions include optimized drivetrain systems, propulsion components and motion technologies designed for industries such as construction, agriculture, mining, material handling and other industrial applications. This expanded portfolio encompasses systems that manage power conveyance to machines and power work functions, including axles, gearboxes, transmissions and related components, as well as motion systems tailored to customer performance and efficiency requirements across both conventional and electrified powertrains.

Product Development and Engineering

We maintain product development and engineering capabilities dedicated to the design, development, refinement and support of our fully automatic transmissions and electric hybrid and fully electric propulsion systems. We believe our customers expect our products to provide unparalleled performance and value defined in various ways, including delivering maximum cargo in minimum time, using the least amount of fuel possible while employing the fewest vehicles possible and experiencing maximum vehicle uptime. In response to those needs and the evolving customer focus on fuel efficiency and reduced emissions, we provide vehicle specification guidelines, propulsion control software and mechanical components to optimize fuel economy while delivering desired vehicle performance.

Further, we are developing new products and technology to improve the fuel efficiency and fuel economy of our fuel-agnostic conventional products, including by allowing engines to operate more efficiently and at lower speeds without compromising performance, and by developing our product portfolio to pair with new engine ratings enabling lower nitrous oxide emissions.

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Sales and Marketing Organization

Our sales and marketing effort is organized along geographic and customer lines and is comprised of marketing, sales and service professionals, supported by customer integration engineers worldwide. In North America, selling efforts in the on-highway end market are organized by distributor area responsibility, OEM sales and, for our large end users, national accounts. Outside North America, we manage our sales, marketing, service and customer integration engineering professionals through regional areas of responsibility. These regional management teams distribute OEM service and customer integration engineering resources globally.

We have developed a marketing strategy to reach OEM customers as well as end users. We target our end users primarily through marketing activities by our sales staff, who directly call on end users and attend local trade shows, targeting specific vocations globally and through our plant tour programs, where end users may test our products on our Indianapolis test track and our enhanced customer experience demonstration track at our Hungary facility.

While our marketing management uses the term “customer” interchangeably for OEMs and end users, the primary objective of our marketing strategy is to create demand for propulsion solutions through:

•

OEM and body builder promotion of our products and incorporation of our propulsion solutions in their commercial vehicle product offerings;

•

Allison representative and/or Allison distributor contact with identified, major end users; and

•

Our network of independent dealers who contact other end users.

The process is interactive, as Allison representatives, Allison distributors, OEMs and dealers educate customers and respond to the specific applications, requirements and needs of numerous specialty markets.

Similarly, we work with customers, dealers and OEMs to educate, improve and simplify how they specify vehicles and certain systems in order to optimize vehicle performance and fuel consumption. Our field organization also works closely with distributors who, in turn, work with dealers to provide end users with education, parts, service and warranty support. The defense group focuses on industry OEMs and collaborative dialogue with OEMs and government leaders to understand program requirements and determine our long-term product development strategy.

Manufacturing

Our manufacturing strategy provides for distributed capability in manufacturing and assembly of our products for the global commercial vehicle market. As of December 31, 2025, our primary manufacturing facilities, located in Indianapolis, Indiana, consist of approximately 2.3 million square feet of usable manufacturing space in five plants. Our high volume on-highway products are produced in multiple global locations (United States, Chennai, India and Szentgotthard, Hungary), while off-highway products are produced in Indianapolis and Chennai, India. Our electric hybrid propulsion and defense tracked products are also produced in Indianapolis, and fully electric propulsion solutions are produced in Auburn Hills, Michigan. In addition, our aluminum die cast components are produced in Lewisburg, Tennessee. We also have established customization and parts distribution centers in the United States, the Netherlands, Brazil, China, Hungary, India and Japan.

As part of the acquisition of the Acquired Off-Highway Business, we acquired approximately 46 manufacturing and assembly plants, in addition to certain other facilities, which facilities will produce our Allison Off-Highway Drive & Motion Systems products.

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Suppliers and Raw Materials

A significant amount of the part numbers that make up our propulsion solutions are purchased from outside suppliers, and during 2025, we purchased approximately $1,022 million of direct materials and components from outside suppliers. The largest elements of our direct spending are aluminum and steel castings and forgings that are formed by our suppliers into our larger components and assemblies for use in our propulsion solutions. Our spending on aluminum and steel raw materials directly and indirectly through our purchase of these components constituted approximately 16% of our direct material and component costs in 2025. The balance of our direct and indirect materials and components costs are primarily composed of value-added services and conversion costs. Our supply contracts, along with an intensive supplier selection and performance monitoring process, have enabled us to establish and maintain close relationships with suppliers and have contributed to our overall operating efficiency and quality.

Intellectual Property

Patents, trademarks, and other proprietary rights are important to the continued success of our business. We also rely upon trade secrets, know-how, continuing technological innovation and licensing opportunities to develop and maintain our competitive position. We protect our proprietary rights through a variety of methods, including confidentiality agreements and proprietary information agreements with suppliers, employees, consultants and others who may have access to our proprietary information. We own and have licensing arrangements for a number of U.S. and foreign patents related to our products and business. We do not consider our business to be dependent on any single patent, nor will the expiration of any single patent materially affect our business. Our current patents will expire over various periods, and we continue to file new patent applications on newly-developed technology.

Seasonality

Overall, the demand for our products is relatively consistent over the year. However, in typical market conditions, the North American truck market experiences a higher level of production in the first half of the year due to fewer holidays and the practice of plant shutdowns in July and December.

Human Capital

At Allison, we believe in the power of our people, our processes and our products. For more than 105 years, we have built our business on these values: Quality, Customer Focus, Integrity, Innovation, and Teamwork. We use a variety of human capital measures in managing our business, including: workforce demographics; equality of opportunity; and employee health and safety.

Workforce Demographics. Our people are a critical component in our continued success, the delivery of our values and the execution of our growth initiatives. As of December 31, 2025, we had a highly skilled workforce of approximately 4,000 employees, with approximately 87% of those employees in the U.S. Approximately 49% of our U.S. employees are represented by the International Union, United Automobile, Aerospace and Agricultural Implement Workers of America (“UAW”) and are subject to a collective bargaining agreement. In January 2024, we entered into a four-year collective bargaining agreement with UAW Local 933 that expires in November 2027.

As part of the acquisition of the Acquired Off-Highway Business, effective as of January 1, 2026, we acquired approximately 8,000 additional employees, excluding contractors, with approximately 8% of those employees in the U.S. Approximately 68% of the U.S. employees that were acquired with the Acquired Off-Highway Business are represented by the UAW or the United Steel, Paper and Forestry, Rubber, Manufacturing, Energy, Allied Industrial and Service Workers International Union (the "USW") and are subject to collective bargaining agreements.

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Equality of Opportunity. Allison recognizes the power of different thought, accepts and respects each individual and strives to create a workplace where everyone can reach their full potential, driving innovation and business results. Allison hires, promotes, trains, and compensates its employees based on merit, experience, or other work-related criteria. Allison values the wide range of backgrounds of our employees. Allison views our diversity as a strength and strives to create work environments that accept differences while promoting productivity and teamwork. Everyone at Allison is responsible for creating and maintaining a productive work environment where the dignity of all employees is respected. Our efforts to promote a respectful workplace include: providing training; utilizing non-traditional recruiting sources, such as organizations focused on veterans and people with disabilities, diverse professional organizations, and schools with diverse student bodies; organizing virtual mentoring programs to connect employees from different locations, departments and backgrounds; and creating multicultural, emerging professionals, and military veterans employee resource groups that are open to all.

Employee Health & Safety. Allison’s overriding priority is to protect the health and safety of each employee. As part of our health and safety programs, Allison is certified in ISO 45001, Occupational Health and Safety Management Systems. ISO 45001 is the only internationally recognized Safety Management System. Employees participate in training focused on health and safety, and metrics are reviewed regularly, including the number of injury incidents that occur and those incidents that result in lost work days. For 2025, we achieved an overall recordable rate of 0.99 at our global locations, meaning that for every 100 employees, 0.99 employees incurred an injury that resulted in recordable medical treatment, and the number of lost work days was 0.30 at our global locations, meaning that for every 100 employees, 0.30 individuals experienced an incident that resulted in days away from work.

Government Regulations

We are subject to a variety of federal, state, local and foreign laws and regulations, including those governing the discharge of pollutants into the air or water, the management and disposal of hazardous substances or wastes, and the cleanup of contaminated sites. Some of our operations require environmental permits and controls to prevent and reduce air and water pollution. These permits are subject to modification, renewal and revocation by issuing authorities. In addition, certain of our products and our customer’s products are subject to certification requirements by a variety of regulatory bodies. We believe we are in substantial compliance with all material environmental laws and regulations applicable to our plants and operations. Historically, our annual costs of achieving and maintaining compliance with environmental, health and safety requirements have not been material to our financial results.

Increasing global efforts to control emissions of carbon dioxide, methane, ozone, nitrogen oxide and other greenhouse gases and pollutants, as well as the shifting focus of regulatory efforts towards total emissions output, have the potential to impact our facilities, costs, products and customers. The U.S. Environmental Protection Agency has taken action to control greenhouse gases from certain stationary and mobile sources. In addition, several states have taken steps, such as the adoption of cap and trade programs or other regulatory systems, to address greenhouse gases. There have also been international efforts seeking legally binding reductions in emissions of greenhouse gases. These developments and further actions that may be taken in the U.S. and in other countries, states or provinces could affect our operations both positively and negatively (e.g., by affecting the demand for or suitability of some of our products).

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In addition to the foregoing, various legislation, regulations and international accords pertaining to climate change have been implemented or are being considered for implementation, particularly as they relate to the reporting of greenhouse gas emissions and sustainability efforts being undertaken, such as the European Union’s Corporate Sustainability Reporting Directive ("CSRD") and California’s Climate Corporate Data Accountability Act and Climate-Related Financial Risk Act. We continue to monitor the development and implementation of such legislation and regulations and are evaluating the impact these laws and regulations may have on the Company, including the extent of our potential disclosures or other reporting requirements. We also continue to regularly report our sustainability efforts in our annual Corporate Social Responsibility Report.

We also may be subject to liability as a potentially responsible party under the Comprehensive Environmental Response, Compensation, and Liability Act and similar state or foreign laws for contaminated properties that we currently own, lease or operate or that we or our predecessors have previously owned, leased or operated and sites to which we or our predecessors sent hazardous substances. Such liability may be joint and several so that we may be liable for more than our share of any contamination, and any such liability may be determined without regard to causation or knowledge of contamination. We or our predecessors have been named potentially responsible parties at contaminated sites from time to time. We do not anticipate our liabilities relating to contaminated sites will be material to our financial results.

Competition

We compete on the basis of product performance, quality, value, distribution capability, service and fuel efficiency, in addition to other factors. We face competition from numerous manufacturers of various types of propulsion solutions for commercial vehicles. Furthermore, we face an increasing amount of competition from vertical integration, as some of our customers are OEMs that manufacture propulsion solutions for their own products. Despite their propulsion solutions manufacturing capabilities, we believe that our existing OEM customers have chosen to purchase certain propulsion solutions from us due to the quality, reliability and strong brand of our propulsion solutions and in order to limit fixed costs, minimize production risks and maintain company focus on commercial vehicle design, production and marketing.

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Corporate Information

Allison Transmission Holdings, Inc. was incorporated in Delaware on June 22, 2007. Our principal executive offices are located at One Allison Way, Indianapolis, IN 46222 and our telephone number is (317) 242-5000. Our internet address is https://www.allisontransmission.com. We file annual, quarterly and current reports, proxy statements and other documents with the SEC under the Securities Exchange Act of 1934, as amended (the “Exchange Act”). These periodic and current reports and all amendments to those reports are available free of charge on the investor relations page of our website at https://ir.allisontransmission.com as soon as reasonably practicable after we electronically file them with, or furnish them to, the SEC. We have included our website address throughout this filing as textual references only. The information contained on, or accessible through, our website is not incorporated into this Annual Report on Form 10-K. The SEC also maintains an Internet site that contains reports, proxy and information statements, and other information regarding issuers that file electronically with the SEC at https://www.sec.gov.

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ITEM 1A. Risk Factors

The following is a cautionary discussion of risks, uncertainties and assumptions that we believe are material to our business. In addition to the factors discussed elsewhere in this Annual Report on Form 10-K, the following are the material factors that, individually or in the aggregate, we believe could make our actual results differ materially from those described in any forward-looking statements.

Risk Factors Summary

The following is a summary of the principal risks that could adversely affect our business, results of operations and financial condition.

Risks Related to Our Business and Operations

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We participate in markets that are competitive, and our competitors’ actions could have a material adverse effect on our business, results of operations and financial condition.

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Volatility in and disruption to the global economic environment may have a material adverse effect on our business, results of operations and financial condition.

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Increases in cost, disruption of supply or shortage of raw materials or components used in our products could harm our business and profitability.

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Prolonged inflation could result in higher costs and decreased margins and earnings.

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Labor cost inflation and employee attraction and retention could have an adverse effect on our business, results of operations and financial condition.

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Certain of our end users operate in highly cyclical industries, which can result in uncertainty and significantly impact the demand for our products, which could have a material adverse effect on our business, results of operations and financial condition.

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In 2025, our sales were concentrated among our top five OEM customers. The loss or consolidation of any one of these customers or the discontinuation of particular vehicle models for which we are a significant supplier could reduce our net sales and have a material adverse effect on our results of operations and financial condition.

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Labor unrest could have an adverse effect on our business, results of operations and financial condition.

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We are subject to cybersecurity risks to operational systems, security systems, and infrastructure owned by Allison or third-party vendors or suppliers.

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Geopolitical risks may have an adverse effect on our results of operations and financial condition.

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Our brand and reputation are dependent on the continued participation and level of service of our numerous independent distributors and dealers.

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In the event of a catastrophic loss of one of our key manufacturing facilities, our business would be adversely affected.

Strategic Risks

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Our success depends on research and development efforts, and we may not be successful in developing or introducing new products and technologies and responding to customer needs.

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Our long-term growth prospects and results of operations may be impaired if the rate of adoption of fully automatic transmissions in commercial vehicles outside North America does not increase.

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Our international operations, in particular our emerging markets, are subject to various risks which could have a material adverse effect on our business, results of operations and financial condition.

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Fluctuations in foreign currency exchange rates could adversely affect our results.

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We may not be able to identify or consummate acquisitions or partnerships or achieve expected benefits from or effectively integrate acquisitions or partnerships, which could harm our growth.

Risks Related to our Acquisition of the Acquired Off-Highway Business

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We expect to incur significant costs in connection with the integration of the Acquired Off-Highway Business.

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Any failure to integrate the Acquired Off-Highway Business and its operations with ours successfully in the expected time frame may adversely affect our results of operations and financial condition.

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We may fail to realize all of the anticipated benefits from the integration of the Acquired Off-Highway Business and its operations after the acquisition or fail to effectively manage our expanded operations.

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Our future results may suffer if we do not effectively manage our expanded operations.

Legal and Regulatory Risks

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Any events that impact our brand name could have an adverse effect on our reputation, cause us to incur significant costs and negatively impact our business, results of operations and financial condition.

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Many of the key patents and unpatented technology we use in our business are licensed to us, not owned by us, and our ability to use and enforce such patents and technology is restricted by the terms of the license.

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We rely on unpatented technology, which exposes us to certain risks.

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Environmental, health and safety laws and regulations may impose significant compliance costs and liabilities on us.

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Our business and financial results may be adversely affected by government contracting risks.

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Provisions of our amended and restated certificate of incorporation and amended and restated bylaws and Delaware law might discourage, delay or prevent a change of control of our company or changes in our management and, as a result, depress the trading price of our common stock.

Risks Related to Our Indebtedness and Financial Risks

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Our indebtedness could adversely affect our financial health, restrict our activities and affect our ability to meet our obligations.

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To service our indebtedness, we will require a significant amount of cash, and our ability to generate cash depends on many factors beyond our control.

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Despite current indebtedness levels, we and our subsidiaries may still be able to incur additional indebtedness, which could further exacerbate the risks associated with our substantial financial leverage.

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Our pension and other post-retirement benefits funding obligations could increase as a result of a variety of factors.

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An impairment in the carrying value of goodwill, other intangible assets or long-lived assets could negatively affect our consolidated results of operations and net worth.

For a more complete discussion of the material risks facing our business, see below.

Risks Related to Our Business and Operations

We participate in markets that are competitive, and our competitors’ actions could have a material adverse effect on our business, results of operations and financial condition.

Our business operates in competitive markets. We compete against other existing or new global manufacturers of transmissions and propulsion solutions for commercial vehicles on the basis of product

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performance, quality, price, distribution capability, service and fuel efficiency in addition to other factors. In addition, we compete with manufacturers developing alternative technologies, including fully electric propulsion solutions, that may or may not require a transmission. A focus on climate change and environmental sustainability, including through regulations enacted and subsidies offered by governmental entities, continues to drive the development and adoption of various alternative technologies, including electric propulsion solutions, in the commercial vehicle industry. If the pace of adoption of electric vehicles proceeds faster than we are anticipating, we may not be in a position to meet customer demand or our competitors may be better positioned to meet customer demand, which may result in a decline in our market share or negatively impact our ability to execute our growth initiatives. Actions by our competitors or accelerated adoption of electric vehicles, in particular if our competitors are able to develop, validate and release new technologies more quickly than we do, could also lead to downward pressure on prices and/or a decline in our market share, either or both of which could adversely affect our results.

In addition, some of our customers or future customers are OEMs that manufacture or could in the future manufacture transmissions, propulsion solutions or alternate technologies, including electric propulsion solutions, for their own products. Despite their manufacturing capabilities, our existing OEM customers have chosen to purchase certain transmissions and propulsion solutions from us due to end user demand. However, we cannot be certain these customers will continue to purchase our products in the future. Increased levels of production insourcing by these customers could result from a number of factors, such as shifts in our customers’ business strategies, acquisition by a customer of another transmission or propulsion solution manufacturer, the inability of third-party suppliers to meet specifications and the emergence of low-cost production opportunities in foreign countries. As a result, these OEMs may use products produced internally or by another manufacturer and no longer choose to purchase products from us. A significant reduction in the level of external sourcing by our OEM customers could significantly impact our net sales and cash flows and, accordingly, have a material adverse effect on our business, results of operations and financial condition.

Volatility in and disruption to the global economic environment, including the impact of an economic recession, trade protectionism and tariffs, and changes in the regulatory and business environments in which we operate, may have a material adverse effect on our business, results of operations and financial condition.

Geopolitical risks, supply chain, labor and energy constraints and inflation have caused and may continue to cause volatility in and disruption to the global economic environment. Historically, the commercial vehicle industry as a whole has been more adversely affected by volatile economic conditions, such as a recession, than many other industries, as the purchase or replacement of commercial vehicles, which are durable items, can be deferred for many reasons, including reduced spending by end users. Future changes in the regulatory and business environments in which we operate, including increased geopolitical risks, trade protectionism and tariffs, may adversely affect our ability to sell our products or source materials needed to manufacture our products.

Furthermore, financial instability or bankruptcy at any of our suppliers or customers could disrupt our ability to manufacture our products and impair our ability to collect receivables, any or all of which may have a material adverse effect on our business, results of operations and financial condition. In addition, some of our customers and suppliers may experience serious cash flow problems and, thus, may find it difficult to obtain financing, if financing is available at all. As a result, our customers’ need for and ability to purchase our products or services may decrease, and our suppliers may increase their prices, reduce their output or change their terms of sale. Any inability of customers to pay us for our products and services, or any demands by suppliers for different payment terms, may materially and adversely affect our business, results of operations and financial condition. Furthermore, our suppliers may not be successful in generating sufficient sales or securing alternate financing arrangements, and therefore may no longer be able to supply goods and services to us. In that event, we would need to find alternate sources for these goods and services, and there is no assurance we would be able to find such alternate sources

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on favorable terms, if at all. Any such disruption in our supply chain could adversely affect our ability to manufacture and deliver our products on a timely basis, and thereby affect our results of operations.

Increases in cost, disruption of supply or shortage of raw materials or components used in our products could harm our business and profitability.

Our products contain various raw materials, including corrosion-resistant steel, non-ferrous metals such as aluminum and nickel, and precious metals such as platinum and palladium. We use raw materials directly in manufacturing and in components that we purchase from our suppliers. We generally purchase components with significant raw material content on the open market. The prices for and availability of these raw materials fluctuate depending on market conditions, including government trade policies and tariffs. Volatility in the prices of raw materials such as steel, aluminum and nickel could increase the cost of manufacturing our products. Additionally, our suppliers are also subject to fluctuations in the prices of raw materials and may attempt to pass all or a portion of such increases on to us. In the event they are successful in doing so, our margins would decline. We may not be able to pass on these costs to our customers, and this could have a material adverse effect on our business, results of operations and financial condition. Even in the event that increased costs can be passed through to customers, our gross margin percentages would decline as the recovery of these costs from customers generally lags six to 12 months.

In 2025, approximately 75% of our total spending on components was sourced from approximately 40 suppliers, many of which are the single source for such components. As of December 31, 2025, all of the suppliers from which we purchase materials and components used in our business were fully validated suppliers, meaning the suppliers’ manufacturing processes and inputs have been validated under a production part approval process (“PPAP”). Furthermore, there are only a limited number of suppliers for certain of the materials used in our business, such as corrosion-resistant steel. As a result, our business is subject to the risk of additional price fluctuations and periodic delays in the delivery of our materials or components if supplies from a validated supplier are interrupted and a new supplier, if one is available, must be validated or materials and components must be purchased from a supplier without a completed PPAP, which could increase our risk of purchasing non-conforming components. Any such price fluctuations or delays, if significant, could harm our profitability or operations. In addition, the loss of a supplier could result in significant material cost increases or reduce our production capacity.

We have experienced, and expect to continue to experience, delays in the availability and receipt of component parts as a result of shortages of available labor in North America and global economic uncertainty, some of which have materially impacted, and may continue to materially impact, our ability to meet customer demand. We also cannot guarantee we will be able to maintain favorable arrangements and relationships with these suppliers. An increase in the cost or a sustained interruption in the supply or shortage of some of these raw materials or components that may be caused by a deterioration of our relationships with suppliers, adverse geopolitical events such as the crisis in the Red Sea, events such as natural disasters and extreme weather events, which may increase in frequency and intensity as a result of climate change, power outages, labor strikes and public health crises, such as pandemics and epidemics, could negatively impact our business, results of operations and financial condition. Although we have agreements with many of our customers that we will pass such price increases through to them, such contracts may be canceled by our customers and/or we may not be able to recoup the costs of such price increases. Additionally, if we are unable to continue to purchase our required quantities of raw materials on commercially reasonable terms, or at all, if we are unable to maintain or enter into purchasing contracts for commodities, or if delivery of materials or component parts from suppliers is delayed or non-conforming, our operations could be disrupted, we may not be able to meet customer demand, and our profitability and our financial results may be materially impacted. While we may experience the supply chain constraints mentioned above across all our product lines, the impacts to our customers are likely to be more pronounced in our

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lower volume product lines, including those supplied to the Allison Transmission Defense and Allison Transmission Off-Highway end markets.

Prolonged inflation could result in higher costs and decreased margins and earnings.

Recent inflationary pressures have resulted in increased raw material, labor, energy, freight and logistics expenses and other costs, which may adversely affect our results of operations. If our costs are subject to continuing significant inflationary pressures, we may not be able to fully offset such higher costs through price increases. Our inability to do so could harm our business and results of operations. In addition, government trade policies and tariffs have increased, and could continue to increase our manufacturing costs, and we may not be able to fully offset such higher costs through price increases.

Labor cost inflation and employee attraction and retention could have an adverse effect on our business, results of operations and financial condition.

Our success depends on our ability to identify, recruit and retain highly skilled, qualified personnel, and there is currently increased competition for talent. We have experienced labor shortages and wage inflation amid low levels of unemployment and workforce availability. As a result, we may not be able to attract and retain qualified personnel, which may impact our ability to manufacture, design and develop our propulsion solutions, satisfy customer demand in a timeframe that meets their desired production schedules and compete effectively. In addition, we continue to experience increased labor costs, including significant labor cost increases under our collective bargaining agreement with the UAW, which will continue to impact our results of operations.

Our business would be adversely affected if we fail to retain key executives, or to adequately plan for the succession of members of our executive management team. While we have succession plans in place for members of our executive management team, and continue to review and update those plans, and certain key executive officers are party to or participants in severance and change in control arrangements, these arrangements do not guarantee that the services of our executive officers will continue to be available to us or that we will be able to find suitable management personnel to replace departing executives on a timely basis.

Some of the markets in which we operate, including agriculture, energy, mining, construction, material handling, distribution and motorhomes, exhibit a high degree of cyclicality. Decisions to purchase our products are largely a result of the performance of these and other industries we serve. If demand for output in these industries decreases, the demand for our products will likely decrease. Demand in these industries is impacted by numerous factors, including prices of commodities, rates of infrastructure spending, housing starts, real estate equity values, interest rates, consumer spending, fuel costs, energy demands, municipal spending, commercial construction and global pandemics, among others. Increases or decreases in these variables globally may significantly impact the demand for our products, which could have a material adverse effect on our business, results of operations and financial condition. If we are unable to accurately predict demand, we may be unable to meet our customers’ needs, resulting in the loss of potential sales, or we may manufacture excess products, resulting in increased inventories and overcapacity in our production facilities, increasing our unit production cost and decreasing our operating margins.

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We have in the past and may in the future derive a significant portion of our net sales from a relatively limited number of OEM customers. For the years ended December 31, 2025, 2024 and 2023, our top five OEM customers accounted for approximately 52%, 55% and 52% of our net sales, respectively. Our top three customers, Daimler AG, PACCAR Inc. and Traton SE, accounted for approximately 18%, 11% and 10%, respectively, of our net sales during 2025. The loss of, or consolidation of, any one of these customers or a significant decrease in business from one or more of these customers, could harm our business, results of operations and financial condition. In addition, the discontinuation of particular vehicle models for which we are a significant supplier could reduce our net sales and have a material adverse effect on our business, results of operations and financial condition.

Labor unrest could have an adverse effect on our business, results of operations and financial condition.

As of December 31, 2025, approximately 49% of our U.S. employees, representing approximately 43% of our total employees, were represented by the UAW and are subject to a collective bargaining agreement. Our current collective bargaining agreement with UAW Local 933 is effective through November 2027. In addition, approximately 68% of the U.S. employees that were acquired with the Acquired Off-Highway Business are represented by the UAW or the USW and are subject to collective bargaining agreements. Any new collective bargaining agreements we negotiate with the UAW or the USW to replace the existing collective bargaining agreements upon their expiration may result in increased costs to us, in particular labor costs, which could have an adverse effect on our results of operations. In addition to our unionized work force, many of our direct and indirect customers and vendors have unionized work forces. Strikes, work stoppages or slowdowns experienced by these customers or vendors or their other suppliers could result in slowdowns or closings of assembly plants that use our products or supply materials for use in the production of our products. Organizations responsible for shipping our products may also be impacted by strikes. Any interruption in the delivery of our products could reduce demand for our products and could have a material adverse effect on us.

In general, we consider our labor relations with all of our employees to be good. However, in the future we may be subject to labor unrest. If strikes, work stoppages or lock-outs at our facilities or at the facilities of our vendors or customers occur or continue for a long period of time, our business, results of operations and financial condition may be materially adversely affected.

We are subject to cybersecurity risks to operational systems, security systems, and infrastructure owned by Allison or third-party vendors or suppliers.

We are at risk for interruptions, outages, and compromises to the confidentiality, integrity or availability of: (i) operational systems, including information technology, business, financial, accounting, product development, data processing, or manufacturing processes, owned by us or our third-party vendors or suppliers; (ii) facility security systems, owned by us or our third-party vendors, customers or suppliers; and/or (iii) vehicle propulsion control modules or other in-product technology, owned by us, our customers or our third-party vendors or suppliers. Such cyber incidents could materially disrupt operational systems (for example, through the deployment of ransomware); result in loss of intellectual property, trade secrets or other proprietary or competitively sensitive information; compromise personally identifiable information of employees, customers, suppliers, or others; jeopardize the security of our facilities; and/or affect the performance of vehicle propulsion control modules or other in-product technology. A cyber incident could be caused by malicious insiders or by third parties using sophisticated, targeted methods to circumvent firewalls, encryption, and other security defenses, including hacking, fraud, trickery, or other

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forms of deception, such as social engineering and phishing, or due to human or technological error, such as misconfigurations, “bugs,” or vulnerabilities in software or hardware used by us or others.

The techniques used by threat actors change frequently and are often difficult to detect. Cyberattacks are expected to accelerate on a global basis in frequency and magnitude as threat actors are increasingly using tools - including artificial intelligence - to evade detection and even remove forensic evidence. As a result, we may be unable to detect, investigate, remediate or recover from future cyberattacks or other incidents, or to avoid a materially adverse impact to our systems, information or business. In addition, remote or hybrid working arrangements at our Company, our customers and many third-party providers increase cybersecurity risks due to the challenges associated with managing remote computing assets and the nature of security vulnerabilities that are present in many non-corporate and home networks. We also deploy scanning tools in our systems that allow us to identify and track known security vulnerabilities, but we cannot guarantee that patches or mitigation measures will be applied in all instances before such vulnerabilities can be exploited by a threat actor.

We and certain of our customers and third-party providers have experienced cyberattacks and other incidents in the past and will continue to experience varying degrees of cyberattacks and incidents in the future. While to date no cybersecurity incidents have had a material impact on our operations or financial results, we cannot guarantee that material incidents will not occur in the future. As a provider of defense products and services to the U.S. government and foreign governments, we are subject to a heightened risk of cyberattacks, including by foreign governments, violent extremist organizations, and transnational criminal organizations. In addition, because certain of our systems are integrated with third-party (e.g., dealers) systems and technology, the circumvention or failure of our cybersecurity measures could compromise the confidentiality, integrity, and availability of those third-party systems, and vice versa.

A significant cyber incident could impact our production capability, harm our reputation and business relationships, impact our competitive position (including compromising our intellectual property assets), and subject us to regulatory actions or litigation and fines and/or penalties, including pursuant to evolving global privacy and security regulations and laws, as well as significant investigative, restoration or remediation costs and/or increased compliance costs. Any of the foregoing could materially affect our business, results of operations and financial condition. There is no guarantee that our measures to prevent, detect and mitigate these threats, including employee and key third-party partner education, monitoring of networks and systems, and maintenance of backup and protective systems, will be successful in preventing or mitigating a cyber incident.

In addition, in many jurisdictions, we are subject to privacy and data protection laws and regulations. These laws and regulations are changing rapidly and becoming increasingly complex. The interpretation and application of data protection laws in the U.S., Europe, and elsewhere are uncertain, evolving and may be inconsistent across jurisdictions. Our failure to comply with these laws and regulations could result in legal liability, significant regulator penalties and fines, or impair our reputation in the marketplace.

Geopolitical risks may have an adverse effect on our results of operations and financial condition, including on the availability of raw materials for our products or component parts, our supply chain, our customers and our long-term sales opportunities.

Political, economic and other conditions in foreign countries and regions, including geopolitical risks such as escalating tensions between China and western countries and the current wars in Ukraine and the Middle East, may have an adverse effect on our results of operations and financial condition. The duration of any such conflict, its impact on the applicable regional and global economy, and the breadth, severity and duration of any applicable sanctions imposed by the U.S. and other governments is uncertain. Extended or expanded conflicts could impact our ability or those of our suppliers or customers to obtain certain raw materials or component parts and could limit the availability and cost of energy throughout Europe, which could increase our costs, impact our ability to deliver

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our products or reduce customer demand. In addition, while we have suspended indefinitely all sales and exports of our products to customers in Russia and Belarus and Russian and Belarusian affiliate owned or controlled entities, certain of our competitors have continued to sell products in Russia during this time, which may have a negative impact on our long-term sales opportunities in Russia.

Our brand and reputation are dependent on the continued participation and level of service of our numerous independent distributors and dealers.

We work with a network of approximately 1,500 independent distributors and dealers (as of December 31, 2025) that provide post-sale service, service parts and support equipment. Because we depend on the pull-through demand generated by end users for our products, any actions by the independent distributors or dealers, which are not in our control, may harm our reputation and damage the brand loyalty among our customer base. In the event that we are not able to maintain our brand reputation because of the actions of our independent distributors and dealers, we may face difficulty in maintaining our pricing positions with respect to some of our products or have reduced demand for our products, which could negatively impact our business, results of operations and financial condition. In addition, if a significant number of independent dealers were to terminate their contracts, it could adversely impact our business, results of operations and financial condition.

In the event of a catastrophic loss of one of our key manufacturing facilities, our business would be adversely affected.

While we manufacture our products in many facilities and maintain insurance covering our facilities, including business interruption insurance, a catastrophic loss of the use of all or a portion of one of our manufacturing facilities due to accident, labor issues, weather conditions, acts of war, political unrest, terrorist activity, natural disaster or extreme weather events, which may increase in frequency and intensity as a result of climate change, public health crises, such as pandemics and epidemics, or otherwise, whether short- or long-term, would have a material adverse effect on our business, results of operations and financial condition. Our most significant concentration of manufacturing is around our corporate headquarters in Indianapolis, Indiana, where we produced approximately 85% of our transmissions in 2025. In addition to our Indianapolis manufacturing facilities, we currently operate manufacturing facilities for our fully electric propulsion solutions in Auburn Hills, Michigan, for our transmissions in both Szentgotthard, Hungary and Chennai, India and for our aluminum die cast components in Lewisburg, Tennessee. We also acquired approximately 46 manufacturing and assembly facilities as part of the acquisition of the Acquired Off-Highway Business, located in approximately 22 countries. In the event of a disruption at the Indianapolis facilities, our other facilities may not be adequately equipped to operate at a level sufficient to compensate for the volume of production at the Indianapolis facility due to their size and the fact that they have not yet been tested for such significant increases in production volume.

Strategic Risks

Our success depends on research and development efforts, and we may not be successful in developing or introducing new products and technologies and responding to customer needs.

Our success depends on our ability to develop or introduce new products and technologies and improve the efficiency and performance of our current products, and we invest significant resources in research and development in order to do so. We currently have enhancements to our existing products and technologies and new products and technologies under development, including electric hybrid and fully electric propulsion solutions, for planned introduction into certain end markets. The development of new products and technologies is difficult, time-consuming and costly and the timetable for commercial release is uncertain. Not all of our new product launches have been successful, and we may not be successful in the future in introducing other new products and responding to customer needs. In addition, it often takes significant time, in some cases multiple fleet buy cycles,

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before customers gain experience with new products and technologies and those new products and technologies become widely-accepted by the market, if at all. Given the early stages of development of some of these new products and technologies, there can be no guarantee of future market acceptance and investment returns with respect to these products. In addition, an increased adoption of electric propulsion solutions could result in lower demand for our fully automatic transmissions and, over time, the demand for related service parts and support equipment, which would impact our margins. If we do not adequately anticipate the changing needs of our customers by keeping pace with improvements and changes in vehicle propulsion technology and developing and introducing new and effective products and technologies on a timely basis, or if the products and technologies we develop do not become market-leading, our competitive position and prospects could be harmed. If our competitors are able to respond to changing market demands and adopt new technologies more quickly than we do, demand for our products could decline, our competitive position could be harmed, our future research and development activities may be constrained due to intellectual property rights of others, licenses for technologies that would enable us to keep pace with our competitors may not be available on commercially reasonable terms if at all and we may not be able to recoup a return on our development investments. Moreover, changing customer demands as well as evolving regulatory, safety and environmental standards could require us to adapt our products and technologies to address such changes. As a result, in the future we may experience delays in the introduction of some or all of our new products or modifications or enhancements of existing products. Furthermore, there may be production delays due to unanticipated technological setbacks, which may, in turn, delay the release of new products to our end users. If the rate of adoption of new technologies, including electric vehicles for the medium- and heavy-duty commercial market, occurs at a pace that is faster than we are anticipating, we may not have products available to meet that accelerated timeframe. If we experience significant delays or increased costs in the production, launch or acceptance of our products and technologies, our business, results of operations and financial condition may be materially adversely affected.

Our long-term growth prospects and results of operations may be impaired if the rate of adoption of fully automatic transmissions in commercial vehicles outside North America does not increase.

Our long-term growth strategy depends in part on an increased rate of automaticity outside North America. As part of that strategy, we have established manufacturing facilities in India and Hungary. We have also dedicated significant human resources to serve markets where we anticipate increased adoption of automaticity. However, manual transmissions remain the market leader outside North America, and there can be no assurance that adoption of automatic transmissions will increase. Factors potentially impacting adoption of automatic transmissions outside of North America include the large existing installed base of manual transmissions, customer preferences for manual transmissions, commercial vehicle OEM vertical integration into manual transmission and AMT manufacturing, increased competition from AMTs, electric propulsion solutions, and other alternative transmission and propulsion solution technologies and failure to further develop the Allison brand. If the rate of adoption of our propulsion solutions, including fully automatic transmissions, does not increase as we have anticipated, our long-term growth prospects and results of operations may be impaired.

Our business is subject to certain risks associated with doing business internationally, particularly in emerging markets. Outside-North America net sales represented approximately 24% of our net sales for 2025. Most of our operations were in the U.S. in 2025, but we also have manufacturing and customization facilities in India and Hungary with a services agreement with Stellantis N.V. and customization capability in Brazil, the Netherlands, China and Japan, and, effective January 1, 2026, manufacturing and assembly facilities located in approximately 14 additional countries as a result of the acquisition of the Acquired Off-Highway Business. Further, we intend to continue to pursue growth opportunities for our business in a variety of business environments outside the U.S.,

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which could exacerbate the risks set forth below. Our international operations are subject to, without limitation, the following risks:

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the burden of complying with multiple and possibly conflicting laws and any unexpected changes in regulatory requirements;

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foreign currency exchange controls, sanctions, import and export restrictions and tariffs, including restrictions promulgated by the Office of Foreign Assets Control of the U.S. Department of the Treasury, and other trade protection regulations and measures;

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political risks, including increased trade protectionism and risks of loss due to civil disturbances, acts of terrorism, acts of war, guerrilla activities and insurrection;

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unstable economic, financial and market conditions and increased expenses as a result of inflation, higher energy costs or higher interest rates;

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difficulties in enforcement of third-party contractual obligations and intellectual property rights and collecting receivables through foreign legal systems;

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difficulties in staffing and managing international operations and the application of foreign labor regulations;

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differing local product preferences and product requirements;

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potentially adverse tax consequences from changes in tax laws, requirements relating to withholding taxes on remittances and other payments by subsidiaries and restrictions on our ability to repatriate dividends from our subsidiaries; and

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exposure to liabilities under anti-corruption and anti-money laundering laws, including the U.S. Foreign Corrupt Practices Act (“FCPA”) and similar laws and regulations in other jurisdictions.

Any one of these factors could materially adversely affect our sales of products or services to international customers or harm our reputation, which could have a material adverse effect on our business, results of operations and financial condition.

Fluctuations in foreign currency exchange rates could adversely affect our results.

We generate revenues and incur costs in multiple currencies. As a result, changes in exchange rates may impact margins on sales outside the U.S. and on products that include components sourced from suppliers located in other countries. In addition, the translation of foreign-denominated revenues, expenses, assets and liabilities into U.S. dollars for financial reporting purposes may result in variability in our reported results. We use natural hedging strategies and may, from time to time, enter into derivative instruments to manage a portion of our foreign currency exposure. However, these measures may not fully offset the effects of exchange rate fluctuations, and our hedging activities may not be effective in mitigating all foreign currency risks, which could adversely affect our results of operations, financial condition and cash flows. Our exposure to such exchange rate fluctuations and foreign currency risks has increased with the acquisition of the Acquired Off-Highway Business.

We may not be able to identify or consummate acquisitions or partnerships or achieve expected benefits from or effectively integrate acquisitions or partnerships, which could harm our growth.

From time to time, we evaluate selective acquisitions, partnerships and strategic investments. Potential and completed acquisitions, including the acquisition of the Acquired Off-Highway Business, and partnerships involve many risks that could have an adverse effect on our business, financial condition or results of operations, including:

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our ability to identify suitable acquisition or partnership candidates, prevail against competing potential acquirers or partners and negotiate and consummate acquisitions or partnerships on terms attractive to us;

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difficulties in integrating personnel and sales forces, operations, manufacturing, logistics, research and development, information technology, communications, purchasing, accounting, marketing, administration and other systems and processes and otherwise assimilating the operations of the acquired company;

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the diversion of resources, including diverting management’s attention from our current operations;

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risks of entering new geographic or product markets in which we have limited or no direct prior experience;

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the potential loss of key customers, employees or suppliers of the acquired company or adverse effects on our existing business relationships with our suppliers and customers;

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the potential incurrence of indebtedness to fund the acquisition or partnerships;

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the acquired business or partnership not achieving anticipated revenues, earnings, cash flow or market share;

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excess capacity;

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failure to achieve the expected synergies or cost savings;

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the need for additional investments post-investment or post-acquisition that could be greater than anticipated;

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the impact of U.S. and foreign competition laws and regulations on our ability to make certain acquisitions, to enter into certain partnerships or to make certain strategic investments;

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inaccurate assessment of undisclosed, contingent or other liabilities or problems and unanticipated costs associated with the acquisition or partnership;

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incorrect estimates made in accounting for acquisitions, incurrence of non-recurring charges and write-off of significant amounts of goodwill that could adversely affect our financial results; and

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dilution of earnings.

We may also face liability with respect to acquired businesses for violations of environmental or other laws occurring prior to the date of our acquisition, and some or all of these liabilities may not be covered by environmental or other insurance secured to mitigate the risk or by indemnification from the sellers from which we acquired these businesses. We could also incur significant costs, including, but not limited to, remediation costs, natural resources damages, civil or criminal fines and sanctions and third-party claims, as a result of past or future violations of, or liabilities associated with, environmental or other laws.

We cannot offer any assurance that we will be able to consummate any future acquisitions, strategic investments, partnerships or other business combinations. If we are unable to identify suitable acquisition candidates or to consummate and successfully integrate any future acquisitions, our business and results of operations may be adversely affected as a result. See also “Risks Related to our Acquisition of the Acquired Off-Highway Business” below for additional discussion of certain risks related to the acquisition of the Acquired Off-Highway Business.

Risks Related to our Acquisition of the Acquired Off-Highway Business

We expect to incur significant costs in connection with the integration of the Acquired Off-Highway Business.

We have incurred, and will continue to incur, substantial costs related to formulating and implementing plans to integrate the Acquired Off-Highway Business, including facilities, systems and service contract consolidation costs and employment‐related costs. We will continue to assess the magnitude of these costs, and additional unanticipated costs may be incurred in connection with the integration of the Acquired Off-Highway Business. These costs, as well as other unanticipated costs and expenses, could adversely affect our business, results of operations and financial condition.

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Any failure to integrate the Acquired Off-Highway Business and its operations with ours successfully in the expected time frame may adversely affect our results of operations and financial condition.

The Acquired Off-Highway Business and its operations may not be integrated successfully with ours. It is possible that the integration process could result in the loss of our or Dana’s key employees, the loss of customers, suppliers, service providers or other business counterparties, the disruption of our ongoing businesses, inconsistencies in standards, controls, procedures and policies, potential unknown liabilities and unforeseen expenses, delays, or regulatory conditions associated with and following completion of the acquisition, higher‐than‐expected integration costs and an overall post‐closing integration process that takes longer than originally anticipated. In addition, the attention of our management team and our resources may be focused on the integration process, which may harm our day-to-day business operations or prevent us from pursuing other opportunities that may be beneficial.

The success of the acquisition of the Acquired Off-Highway Business will depend, in part, on our ability to achieve the expected opportunities, cost savings, operating synergies and other benefits from integrating the Acquired Off-Highway Business. However, the anticipated benefits of the acquisition may not be realized fully or at all, may take longer to realize than expected, or may result in other adverse effects that we do not currently foresee, which could adversely affect our business, results of operations and financial condition. In addition, the estimates and assumptions that we and Dana have made when evaluating the anticipated benefits from the acquisition may not be accurate, and there could be potential unknown liabilities and unforeseen expenses associated with the acquisition that could adversely impact us. In addition, following the acquisition, the size and complexity of our businesses and operations increased significantly. Our future success will depend, in part, upon our ability to manage this expanded business.

Legal and Regulatory Risks

Any events that impact our brand name, including if the products we manufacture or distribute are found to be defective, could have an adverse effect on our reputation, cause us to incur significant costs and negatively impact our business, results of operations and financial condition.

We face exposure to product liability claims in the event that the use of our products has, or is alleged to have, resulted in injury, death or other adverse effects. We currently maintain product liability insurance coverage, but we cannot guarantee that we will be able to obtain such insurance on acceptable terms in the future, if at all, or that any such insurance will provide adequate coverage against potential claims. Product liability claims can be expensive to defend and can divert the attention of management and other personnel for long periods of time, regardless of the ultimate outcome. An unsuccessful product liability defense could have a material adverse effect on our business, results of operations, financial condition or prospects. If one of our products is determined to be defective, we may face substantial warranty costs and may be responsible for significant costs associated with a product recall or a redesign. We have had defect and warranty issues associated with certain of our products in the past, and similar product defects may occur in the future. See "Note 10. Product Warranty Liabilities” of Notes to Consolidated Financial Statements included in Part II, Item 8., of this Annual Report on Form 10-K for additional details regarding these warranty issues.

Furthermore, our business depends on the strong brand reputation we believe we have developed. In addition to the risk of defective products, we also face significant risks in our efforts to penetrate new markets, where we have limited brand recognition. We also rely on our reputation with end users of our products to specify our products when purchasing new vehicles from our OEM customers. In the event we are not able to maintain or enhance our

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brand in these new markets or our reputation is damaged in our existing markets as a result of product defects or recalls, we may face difficulty in maintaining our pricing positions with respect to some of our products or experience reduced demand for our products, which could negatively impact our business, results of operations and financial condition.

Additionally, we license the “Allison Transmission” name and certain related trademarks to third parties. If any third party uses the trade name “Allison Transmission” in ways that adversely affect such trade name or trademark, our reputation could suffer damage, which in turn could have a material adverse effect on our business, results of operations and financial condition.

Protecting our intellectual property rights is critical to our ability to compete and succeed as a company. General Motors Company (“GM”) has granted us an irrevocable, perpetual, royalty-free, worldwide license under a large number of U.S. and foreign patents and patent applications, as well as certain unpatented technology and know-how, to design, develop, manufacture, use and sell fully automatic transmissions and electric hybrid propulsion solutions for use in certain vocational vehicles, defense vehicles and off-road products. For the bulk of the intellectual property licensed to us, our license is exclusive with respect to the design, development, manufacture, use and sale of fully automatic transmissions and electric hybrid propulsion solutions in vocational vehicles above certain weight rating thresholds, certain defense vehicles and certain off-road products. It is non-exclusive with respect to certain other products that are within the scope of the licensed patents or to which the licensed technology can be applied. GM continues to own such patents and technology, and GM has the right, in the first instance, to control the maintenance, enforcement and defense of such patents and the prosecution of the licensed patent applications. In addition, our ability to sublicense our rights is limited.

We rely on unpatented technology, which exposes us to certain risks.

We currently rely, and may continue in the future to rely, on unpatented proprietary technology. In such regard, we cannot be assured that any of our applications for protection of our intellectual property rights will be approved or that others will not infringe or challenge our intellectual property rights. It is possible our competitors will independently develop the same or similar technology or otherwise obtain access to our unpatented technology.

Although we believe the loss or expiration of any single patent would not have a material effect on our business, results of operations or financial condition, there can be no assurance that any one, or more, of the patents or any other intellectual property owned by or licensed to us will not be challenged, invalidated or circumvented by third parties. In fact, a number of the patents licensed to us are set to expire in the next few years. When a patent expires, the inventions it discloses can be used freely by others. Thus, the competitive advantage that we gain from the patents licensed to us will decrease over time, and a greater burden will be placed on our own research and development and licensing efforts to develop and otherwise acquire technologies to keep pace with improvements of transmission-related technology in the marketplace. We enter into confidentiality and invention assignment agreements with employees, and into non-disclosure agreements with suppliers and appropriate customers so as to limit access to and disclosure of our proprietary information. We cannot be assured that these measures will provide meaningful protection for our trade secrets, know-how or other proprietary information in the event of any unauthorized use, misappropriation or disclosure. If we are unable to maintain the proprietary nature of our technologies, our ability to sustain margins on some or all of our products may be affected, which could reduce our sales and profitability. Moreover, the protection provided for our intellectual property by the laws and courts of foreign nations may not be as advantageous to us as the protection available under U.S. law.

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Environmental, health and safety laws and regulations may impose significant compliance costs and liabilities on us.

Our manufacturing operations are subject to many environmental, health and safety laws and regulations governing emissions to air, discharges to water, the generation, handling and disposal of waste and the cleanup of contaminated properties. Compliance with these laws and regulations is costly. We have incurred and expect to continue to incur significant costs to maintain or achieve compliance with applicable environmental, health and safety laws and regulations. Moreover, regulatory bodies are increasingly adopting regulations that target limiting greenhouse gases and combating climate change, which may impact our ability to sell our current products or require us to develop new products or technologies. If these environmental, health and safety laws and regulations that impact our operations or products become more stringent or expand to include a larger portion of our products or our customers’ products in the future, we could incur additional costs in order to ensure that our business and products comply with such regulations. In addition, we may not be successful in developing products or technologies that comply with, or the vehicle or customer OEMs to which we sell our products may choose not to comply with, such laws and regulations, which could impact our ability to sell our products in certain locations, negatively impact our business and result in a loss of market share. Furthermore, if our products that are already placed in service are found to be non-compliant with certain laws, regulations and certifications, we may incur additional costs and fines. We cannot assure that we are in full compliance with all environmental, health and safety laws and regulations. Our failure to comply with applicable environmental, health and safety laws and regulations and permit requirements could result in civil or criminal fines, penalties or enforcement actions, third-party claims for property damage and personal injury, requirements to clean up property or to pay for the costs of cleanup or regulatory or judicial orders enjoining or curtailing operations or requiring corrective measures, including the installation of pollution control equipment or remedial actions. Our failure to comply could also result in our failure to secure adequate insurance for our business, resulting in significant exposure, diminished ability to hedge our risks and material modifications of our business operations.

Concern over climate change continues to result in new legal and regulatory requirements designed to mitigate the effects of climate change on the environment, such as actions taken by the U.S. Environmental Protection Agency and several states to address greenhouse gas emissions, the European Union’s CSRD and California’s Climate Corporate Data Accountability Act and Climate-Related Financial Risk Act. We are experiencing increased compliance burdens and costs in addressing our obligations under these new legal and regulatory obligations, and these new legal and regulatory obligations may adversely affect raw material sourcing, manufacturing operations and the distribution of our products.

We may be subject to liability as a potentially responsible party under the Comprehensive Environmental Response, Compensation and Liability Act and similar state or foreign laws for contaminated properties that we currently own, lease or operate or that we or our predecessors have previously owned, leased or operated, and sites to which we or our predecessors sent hazardous substances. Such liability may be joint and several so that we may be liable for more than our share of any contamination, and any such liability may be determined without regard to causation or knowledge of contamination. We or our predecessors have been named potentially responsible parties at contaminated sites from time to time.

There can be no assurance that future environmental remediation obligations will not have a material adverse effect on our results of operations and financial condition. In addition, we occasionally evaluate alternatives with respect to our facilities, including possible dispositions or closings. Investigations undertaken in connection with these activities may lead to discoveries of contamination that must be remediated, and closings of facilities may trigger remediation requirements that are not applicable to operating facilities. We may also face lawsuits brought by third parties that either allege property damage or personal injury as a result of, or seek reimbursement for costs associated with, such contamination.

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Our business and financial results may be adversely affected by government contracting risks.

We are subject to various laws and regulations applicable to parties doing business with governmental entities, including laws and regulations governing performance of government contracts, capital allocations, the use and treatment of government furnished property and the nature of materials used in our products. We may be unilaterally suspended or barred from conducting business with a governmental entity, or become subject to fines or other sanctions if we are found to have violated such laws or regulations. As a result of the need to comply with these laws and regulations, we are subject to increased risks of governmental investigations, civil fraud actions, criminal prosecutions, whistleblower lawsuits and other enforcement actions. The laws and regulations to which we are subject include, but are not limited to, Export Administration Regulations, the Federal Acquisition Regulation, International Traffic in Arms Regulations, regulations from the Bureau of Alcohol, Tobacco, Firearms and Explosives and the FCPA in the U.S., as well as the regulations and laws applicable to government contracting in countries outside the U.S. The risks may be amplified in non-U.S. jurisdictions due to differing legal regimes, export controls, trade restrictions, currency and payment practices, and political and economic instability.

U.S. government contracts are subject to modification, curtailment or termination by the U.S. government without prior written notice, either for convenience or for default as a result of our failure to perform under the applicable contract. If terminated by the U.S. government as a result of our default, we could be liable for additional costs the U.S. government incurs in acquiring undelivered goods or services from another source and any other damages it suffers. Additionally, we cannot assign prime U.S. government contracts without the prior consent of the U.S. government contracting officer, and we are required to register with the Central Contractor Registration Database. Furthermore, the U.S. government periodically audits our governmental contract costs, which could result in fines, penalties or adjustment of costs and prices under the contracts. The result of, or expiration of the statute of limitations for, such audits could have an impact on reported liabilities, net income and cash flow from operations.

As our business increasingly includes contracts with governmental customers outside the U.S., we are subject to comparable risk of modification, suspension or termination, as well as audit, compliance and performance requirements, under foreign legal and regulatory regimes. These risks may be heightened by differing procurement practices, payment terms, export controls, political or regulatory developments, and other complexities inherent in contracting with non-U.S. governmental entities.

Our amended and restated certificate of incorporation and amended and restated bylaws and certain provisions of the General Corporation Law of the State of Delaware contain provisions that could discourage, delay or prevent a change in control of our Company or changes in our management that the stockholders of our Company may deem advantageous. These provisions:

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authorize the issuance of blank check preferred stock that our Board of Directors could issue to increase the number of outstanding shares and to discourage a takeover attempt;

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prohibit our stockholders from calling a special meeting of stockholders;

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prohibit stockholder action by written consent, which requires all stockholder actions to be taken at a meeting of our stockholders;

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provide that the Board of Directors is expressly authorized to adopt, or to alter or repeal, our bylaws;

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establish advance notice requirements for nominations for election to our Board of Directors or for proposing matters that can be acted upon by stockholders at stockholder meetings; and

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require the approval of holders of at least two-thirds of the outstanding shares of common stock to amend the bylaws and certain provisions of the certificate of incorporation.

These anti-takeover defenses could discourage, delay or prevent a transaction involving a change in control of our Company that our stockholders may believe to be in their best interests. These provisions could also discourage proxy contests and make it more difficult for our stockholders to elect directors of their choosing and cause us to take corporate actions other than those they desire.

Risks Related to Our Indebtedness and Financial Risks

Our indebtedness could adversely affect our financial health, restrict our activities and affect our ability to meet our obligations.

As of December 31, 2025, we had total indebtedness of $2,909 million, and we would have been able to borrow an additional $745 million, net of $5 million of outstanding letters of credit, under Allison Transmission Inc.’s (“ATI”), our wholly-owned subsidiary, revolving credit facility with commitments in the amount of $750 million due March 2029 (“Revolving Credit Facility”). As of December 31, 2025, we had no outstanding borrowings against the Revolving Credit Facility. At December 31, 2025, $509 million of indebtedness was associated with ATI’s term loan facility due March 2031 (“Term Loan”, and together with the Revolving Credit Facility, the “Senior Secured Credit Facility”), $400 million of indebtedness was associated with ATI’s 4.75% Senior Notes due October 2027 (“4.75% Senior Notes”), $500 million of indebtedness was associated with ATI’s 5.875% Senior Notes due June 2029 (“5.875% Senior Notes 2029”), $1,000 million of indebtedness was associated with ATI’s 3.75% Senior Notes due January 2031 (“3.75% Senior Notes”) and $500 million of indebtedness was associated with ATI’s 5.875% Senior Notes due December 2033 (“5.875% Senior Notes 2033”, and together with the 4.75% Senior Notes, 5.875% Senior Notes 2029 and 3.75% Senior Notes, the “Senior Notes”). For a complete description of the terms of the Senior Secured Credit Facility and the Senior Notes, see "Note 8. Debt” of Notes to Consolidated Financial Statements included in Part II, Item 8., of this Annual Report on Form 10-K.

On January 2, 2026, we amended the Second Amended and Restated Credit Agreement dated as of March 29, 2019, as amended (the “Credit Agreement”), to provide for an incremental term loan facility under the Credit Agreement in an aggregate principal amount equal to $1,200 million (the “Incremental Term Loan”) and increased the commitments under the Revolving Credit Facility by $250 million to an aggregate principal amount of up to $1,000 million. We used the proceeds of the Incremental Term Loan and also borrowed $300 million under the Revolving Credit Facility to pay a portion of the consideration for the acquisition of the Acquired Off-Highway Business and fees, costs and expenses related to the acquisition.

Our indebtedness could have important consequences. For example, it could:

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make it more difficult for us to satisfy our obligations under our indebtedness;

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require us to further dedicate a substantial portion of our cash flow from operations to payments of principal and interest on our indebtedness, thereby reducing the availability of our cash flow to fund acquisitions, working capital, capital expenditures, research and development efforts and other general corporate purposes;

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increase our vulnerability to and limit our flexibility in planning for, or reacting to, downturns or changes in our business and the industry in which we operate;

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restrict us from making strategic acquisitions or cause us to make non-strategic divestitures;

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expose us to the risk of increased interest rates as borrowings under the Senior Secured Credit Facility are subject to variable rates of interest;

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place us at a competitive disadvantage compared to our competitors that have less debt; and

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limit our ability to borrow additional funds.

In addition, the Revolving Credit Facility contains a maximum total senior secured leverage ratio. The Senior Secured Credit Facility and the indentures governing the Senior Notes also contain other negative and affirmative covenants that will limit our ability to engage in activities that may be in our long-term best interests. Our failure to comply with any of the covenants could result in an event of default which, if not cured or waived, could result in the acceleration of all of our indebtedness.

To service our indebtedness, we will require a significant amount of cash, and our ability to generate cash depends on many factors beyond our control.

Our ability to make cash payments on our indebtedness and to fund planned capital expenditures will depend on our ability to generate significant operating cash flow in the future. This, to a significant extent, is subject to general economic, financial, competitive, legislative, regulatory and other factors that are beyond our control.

We cannot ensure that our business will generate sufficient cash flow from operations or that future borrowings will be available to us under the Revolving Credit Facility in an amount sufficient to enable us to pay our indebtedness or to fund our other liquidity needs. In such circumstances, we may need to refinance all or a portion of our indebtedness on or before maturity. We cannot ensure that we will be able to refinance any of our indebtedness on commercially reasonable terms or at all. If we cannot service our indebtedness, we may have to take actions such as selling assets, seeking additional equity or reducing or delaying capital expenditures, strategic acquisitions, investments and alliances. We cannot ensure that any such actions, if necessary, could be effected on commercially reasonable terms or at all.

We and our subsidiaries may be able to incur additional indebtedness in the future because the terms of our indebtedness do not fully prohibit us or our subsidiaries from doing so. Subject to covenant compliance and certain conditions, our indebtedness as of December 31, 2025 permitted additional borrowing, including total borrowing up to $745 million under the Revolving Credit Facility, net of $5 million in letters of credit. If new debt is added to our current debt levels and our subsidiaries’ current debt levels, the related risks that we and they now face could intensify.

Our pension and other post-retirement benefits funding obligations could increase as a result of a variety of factors.

Our earnings may be positively or negatively impacted by the amount of income or expense recorded for our defined benefit pension plans and other post-retirement benefits (“OPEB”). Accounting principles generally accepted in the United States of America (“GAAP”) require that income or expense for defined benefit pension plans be calculated at the annual measurement date, or more frequently if certain events occur, using actuarial assumptions and calculations. These calculations reflect certain assumptions, the most significant of which relate to the capital markets, interest rates, health care inflation rates and other economic conditions. Changes in key economic indicators can change these assumptions. These assumptions, along with the actual value of assets at the measurement date, will impact the calculation of pension expense for the year. Although GAAP pension expense and pension contributions are not directly related, the key economic indicators that affect GAAP pension expense also affect the amount of cash that we would contribute to our defined benefit pension plans. Because the values of these defined benefit pension plans’ assets have fluctuated and will fluctuate in response to changing market conditions, the amount of gains or losses that will be recognized in subsequent periods, the impact on the funded status of the defined benefit pension plans and the future minimum required contributions, if any, could have

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a material adverse effect on our business, results of operations and financial condition. The magnitude of such impact cannot be determined with certainty at this time. However, the effect of a one percentage point decrease in the assumed discount rate would result in an increase in the December 31, 2025 defined benefit pension plans obligation of approximately $13 million. Likewise, a one percentage point decrease in the effective interest rate for determining defined benefit pension plans contributions would result in an increase in the minimum required contributions for 2026 of approximately $2 million. Similarly, a one percentage point decrease in the assumed discount rate would result in an increase in the December 31, 2025 OPEB obligation of approximately $6 million. As of December 31, 2025, the unfunded status of our defined benefit pension plans was $4 million and the unfunded status of our OPEB plan was $66 million.

An impairment in the carrying value of goodwill, other intangible assets or long-lived assets could negatively affect our consolidated results of operations and net worth.

Pursuant to GAAP, we are required to assess our goodwill and indefinite-lived intangible assets to determine if they are impaired on an annual basis, or more often if events or changes in circumstances indicate that impairment may have occurred. Intangible assets with finite lives are amortized over the useful life and are reviewed for impairment on triggering events such as events or changes in circumstances indicating that an impairment may have occurred. If the testing performed indicates that impairment has occurred, we are required to record a non-cash impairment charge for the difference between the carrying value of the goodwill and the implied fair value of the goodwill or the carrying value of the intangible assets and the fair value of the intangible assets in the period the determination is made. Disruptions to our business, end market conditions, protracted economic weakness, the unsuccessful development of a product and unexpected significant declines in operating results may result in charges for goodwill and other asset impairments. See "Note 2. Summary of Significant Accounting Policies” and "Note 6. Goodwill and Other Intangible Assets” of Notes to Consolidated Financial Statements included in Part II, Item 8., of this Annual Report on Form 10-K for additional details.

The carrying value of long-lived assets is evaluated whenever events or circumstances indicate that the carrying value of a long-lived asset may not be recoverable. Events or circumstances that would result in an impairment review primarily include a significant change in the use of an asset, a significant change in the projected future cash flows generated by an asset or the planned sale or disposal of an asset. The asset would be considered impaired when there is no future use planned for the asset or the future net undiscounted cash flows generated by the asset or asset group are less than its carrying value. An impairment loss would be recognized based on the amount by which the carrying value exceeds fair value and could have a material adverse effect on the results of our operations. See "Note 2. Summary of Significant Accounting Policies” and "Note 5. Property, Plant and Equipment” of Notes to Consolidated Financial Statements included in Part II, Item 8., of this Annual Report on Form 10-K for additional details.

ITEM 1B. UNRESOLVED STAFF COMMENTS

None.

ITEM 1C. CYBERSECURITY

We have developed and implemented a cybersecurity risk management program intended to protect the confidentiality, integrity, and availability of our critical systems and information.

Our cybersecurity risk management program is guided by the National Institute of Standards and Technology Cybersecurity Framework (“NIST CSF”). This does not imply that we meet any particular technical standards, specifications, or requirements, only that we use the NIST CSF as a framework to help us identify, assess, and manage cybersecurity risks relevant to our business.

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Our cybersecurity risk management program is integrated into our overall enterprise risk management program and shares common methodologies, reporting channels and governance processes that apply across the enterprise risk management program to other legal, compliance, strategic, operational, and financial risk areas.

Key aspects of our cybersecurity risk management program include:

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Risk assessments designed to help identify material cybersecurity risks to our critical systems and information;

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A security team principally responsible for managing (1) our cybersecurity risk assessment processes, (2) our security controls, and (3) our response to cybersecurity incidents;

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The use of external service providers, where appropriate, to assess, test or otherwise assist with aspects of our security controls;

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Cybersecurity awareness training of our employees, key third-party partners, incident response personnel, and senior management;

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A cybersecurity incident response plan that includes procedures for responding to cybersecurity incidents; and

•

A third-party risk management process for key third-party vendors and suppliers.

We have not identified risks from known cybersecurity threats, including as a result of any prior cybersecurity incidents, that have materially affected us, including our operations, business strategy, results of operations, or financial condition. We face certain ongoing risks from cybersecurity threats that, if realized, are reasonably likely to materially affect us, including our operations, business strategy, results of operations, or financial condition. See “Risk Factors – We are subject to cybersecurity risks to operational systems, security systems, or infrastructure owned by Allison or third-party vendors or suppliers" in Part I, Item 1A. of this Annual Report on Form 10-K.

Cybersecurity Governance

Our Board considers cybersecurity risk as part of its risk oversight function and has delegated to its Audit Committee oversight of cybersecurity and other information technology risks. Our Audit Committee oversees management’s implementation of our cybersecurity risk management program.

Our Audit Committee receives quarterly reports from management on our cybersecurity risks. In addition, management updates the Audit Committee, as necessary, regarding significant cybersecurity incidents.

The Audit Committee reports to the full Board regarding its activities, including those related to cybersecurity. The full Board also receives briefings from management on our cybersecurity risk management program. Board members receive presentations on cybersecurity topics from our Chief Information Security Officer ("CISO"), internal security staff or external experts as part of the Board’s continuing education on topics that impact public companies.

Our CISO has primary responsibility for assessing and managing our material risks from cybersecurity threats and supervises both our internal cybersecurity operations team and our retained external cybersecurity consultants. Our management team, which includes our CISO as well as our Chief Executive Officer, Chief Financial Officer, General Counsel and Chief Information Officer, has overall responsibility for implementing our cybersecurity risk management program.

Our management team, led by our CISO, stays informed about and monitors the prevention, detection, mitigation, and remediation of key cybersecurity risks and incidents through various means, which may include briefings with internal cybersecurity team members and external consultants, threat intelligence and other information obtained from public or private sources, and alerts and reports produced by security tools deployed in

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our information technology environment.Our CISO has over 30 years of experience in leading strategy and operations across information technology, cybersecurity and cloud infrastructure areas for entities in the public, private, government and military sectors. In addition, our CISO leads the operational cybersecurity team, which has an average of over 10 years of experience. Collectively, the members of the operational cybersecurity team have various certifications, including, but not limited to, CISSP, GSOM, GCIA, GCIH, CISA, CCSK, SSCP, GPEN, CEH, and CISM.

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ITEM 2. PROPERTIES

Our world headquarters, which we own, is located at One Allison Way, Indianapolis, Indiana 46222. As of December 31, 2025, we have 17 manufacturing and certain other facilities in eight countries. The following table sets forth certain information regarding our significant facilities as of December 31, 2025.

Plant Location ApproximateSize (ft2) Owned /Leased Description

Plant #3 Indianapolis 927,000 Own Engineering, Operational Support

Plant #4 Indianapolis 425,900 Own Manufacturing

Plant #6 Indianapolis 431,500 Own Manufacturing

Plant #12 Indianapolis 534,900 Own Manufacturing

Plant #14 Indianapolis 481,100 Own Manufacturing

Plant #15 Indianapolis 391,700 Own Manufacturing

Plant #17 Indianapolis 389,000 Own Parts Distribution Center

Innovation Center Indianapolis 96,000 Own Engineering, Research and Development

Walker Die Casting Lewisburg, Tennessee, USA 774,100 Own Manufacturing

Chennai India 551,551 Own Manufacturing

Szentgotthard Hungary 149,000 Own Manufacturing & Customization

In addition, in connection with the acquisition of the Acquired Off-Highway Business, effective as of January 1, 2026, we acquired approximately 46 additional manufacturing and assembly plants and approximately 30 other facilities located in 24 countries.

We believe all our facilities are suitable for their intended purpose, are being efficiently utilized and provide adequate capacity to meet demand for the next several years. The table above does not include sales offices located in various countries.

ITEM 3. LEGAL PROCEEDINGS

We are subject to various contingencies, including routine legal proceedings and claims arising out of the normal course of business. These proceedings primarily involve commercial claims, product liability claims, personal injury claims and workers’ compensation claims. The outcome of these lawsuits, legal proceedings and claims cannot be predicted with certainty. Nevertheless, we believe the outcome of any of these currently existing proceedings, even if determined adversely, would not have a material adverse effect on our financial condition or results of operations. See "Note 18. Commitments and Contingencies” of Notes to Consolidated Financial Statements included in Part II, Item 8., of this Annual Report on Form 10-K.

ITEM 4. MINE SAFETY DISCLOSURES

Not applicable.

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PART II.

ITEM 5. Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities

Market Information

Our common stock is listed on the New York Stock Exchange under the symbol “ALSN.”

Holders

As of February 5, 2026, there were approximately 306,855 stockholders of record of our common stock, which includes the actual number of holders registered on our books and holders of shares in “street name” or persons, partnerships, associations, corporations or other entities identified in security position listings maintained by depositories.

Unregistered Sales of Equity Securities

During the period covered by this Annual Report on Form 10-K, we did not offer or sell any equity securities that were not registered under the Securities Act of 1933, as amended (the “Securities Act”).

Issuer Purchases of Equity Securities

Our current stock repurchase program (the "Repurchase Program") was authorized by the Board of Directors in 2016, with increases approved by the Board of Directors on each of November 8, 2017, July 30, 2018, May 9, 2019, February 24, 2022 and February 20, 2025, which in the aggregate total authorized repurchases of $5,000 million in shares of our common stock. The Repurchase Program has no termination date, and the timing and amount of stock purchases are subject to market conditions and corporate needs. The Repurchase Program may be modified, suspended or discontinued at any time at our discretion.

The following table sets forth information related to our repurchase of our common stock on a monthly basis during the three months ended December 31, 2025:

(1)

These values reflect repurchases made under the Repurchase Program.

Issuances Under Equity Compensation Plans

For information regarding the securities authorized for issuance under our equity compensation plans, see Part III, Item 12. of this Annual Report on Form 10-K.

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Comparative Stock Performance Graph

The information included under the heading “Comparative Stock Performance Graph” in this Item 5. of Part II of this Annual Report on Form 10-K shall not be deemed to be “soliciting material” or subject to Regulation 14A or 14C, shall not be deemed “filed” for purposes of Section 18 of the Exchange Act, or otherwise subject to the liabilities of that section, nor shall it be deemed incorporated by reference in any filing under the Securities Act or the Exchange Act.

Set forth below is a graph comparing the total cumulative returns of ALSN, the S&P 500 Index and an index of peer companies selected by us. Our peer group includes Donaldson Company, Inc., Graco Inc., Roper Technologies, Inc., Gentex Corporation, Rockwell Automation, Inc. and Sensata Technologies Holding PLC. The graph assumes $100 was invested on December 31, 2020 in our common stock and each of the indices and that all dividends, if any, are reinvested.

ITEM 6. [RESERVED]

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ITEM 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations

The following discussion contains forward-looking statements regarding industry trends, our expectations regarding our future performance, liquidity and capital resources and other non-historical statements that involve risks and uncertainties. Our actual results may differ materially from those discussed in or implied by the forward-looking statements as a result of various factors, including, without limitation, those set forth under Part I, Item 1A., “Risk Factors,” and other matters included elsewhere in this Annual Report on Form 10-K. The following discussion and analysis of our financial condition and results of operations should be read in conjunction with our Consolidated Financial Statements and the notes thereto included elsewhere in this Annual Report on Form 10-K.

This section of this Annual Report on Form 10-K generally discusses 2025 and 2024 items and year-over-year comparisons between 2025 and 2024. A detailed discussion of 2023 items and year-over-year comparisons between 2024 and 2023 that are not included in this Annual Report on Form 10-K can be found in “Management’s Discussion and Analysis of Financial Condition and Results of Operations” in Part II, Item 7. of our Annual Report on Form 10-K for the year ended December 31, 2024, as filed with the SEC on February 13, 2025.

Overview

We are a global leader in high-performance mobility and work solutions built for the needs of the modern industrial world. The business was founded in 1915 and has been headquartered in Indianapolis, Indiana since inception. Allison is traded on the New York Stock Exchange under the symbol, “ALSN”.

Recent Developments

On June 11, 2025, we entered into a Stock Purchase Agreement (the “Purchase Agreement”) with Dana to acquire the Acquired Off-Highway Business (the "Acquisition"). Also on June 11, 2025, in connection with the entry into the Purchase Agreement, we entered into a commitment letter (the “Commitment Letter”) with a group of lenders (the "Lenders"), pursuant to which the Lenders committed to provide a 364-day senior unsecured bridge term loan facility (the “Bridge Facility”), in an aggregate principal amount of up to $2,000 million. As of December 31, 2025, the Bridge Facility aggregate commitment principal amount had been reduced to $500 million as a result of the issuance of $500 million aggregate principal amount of our 5.875% Senior Notes due December 2033 (“5.875% Senior Notes 2033”) and our election to voluntarily reduce the aggregate commitments under the facility.

On January 1, 2026, the Acquisition was completed for a purchase price of approximately $2,732 million, subject to certain adjustments, using a combination of cash on hand, the $500 million of proceeds from the issuance of the 5.875% Senior Notes 2033, $1,200 million of proceeds from the Incremental Term Loan, and $300 million borrowed under the Revolving Credit Facility. No amount was drawn from the Bridge Facility, and it was terminated upon the completion of the Acquisition.

As a result of the Acquisition, we now offer an expanded portfolio of drivetrain, motion and propulsion solutions, providing complementary product breadth and an enhanced ability to support customers across multiple end markets. The Acquired Off-Highway Business has historically served end markets with demand characteristics that differ from our traditional on-highway markets, contributing to a more diversified portfolio.

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Following the Acquisition, we continue to operate under the Allison name, but our operations are now comprised of two business units: Allison Transmission and Allison Off-Highway Drive & Motion Systems. Business unit leadership is located globally, reflecting the international nature of our operations and the importance of local market insights, sourcing, production and customer support.

Allison Transmission offers more than 200 different models compatible with more than 500 combinations of engine brands, models and ratings, including diesel, gasoline, natural gas and other alternative fuels. In addition, Allison Transmission has developed thousands of proprietary calibrations available for use with our electronic control modules, enabling tailored performance across a broad range of customer applications.

Allison Off-Highway Drive & Motion Systems provides drivetrain and motion solutions for a wide range of mobile and stationary off-highway equipment. These solutions include optimized drivetrain systems, propulsion components and motion technologies designed for industries such as construction, agriculture, mining, material handling and other industrial applications. The portfolio encompasses systems that manage power conveyance to machines and power work functions, including axles, gearboxes, transmissions and related components, as well as motion systems tailored to customer performance and efficiency requirements across both conventional and electrified powertrains. The global engineering, manufacturing and service footprint of the Acquired Off-Highway Business supports localized responsiveness and technical support for customers in key off-highway end markets.

Trends Impacting Our Business

In 2026, we expect to have higher net sales driven by our North America On-Highway and Defense end markets and net sales for Allison Off-Highway Drive & Motion Systems driven by our Construction & Material Handling end market.

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Full Year 2025 and 2024 Net Sales by End Market (dollars in millions)

End Market 2025Net Sales 2024Net Sales % Variance

Outside North America On-Highway 507 493 3 %

Service Parts, Support Equipment and Other 643 663 (3 )%

North America On-Highway end market net sales were down 12% for the year ended December 31, 2025 compared to the year ended December 31, 2024, principally driven by lower demand for medium-duty and class 8 vocational trucks, partially offset by price increases on certain products and market share gains for hybrid propulsion systems for transit buses.

Outside North America On-Highway end market net sales were up 3% for the year ended December 31, 2025 compared to the year ended December 31, 2024, principally driven by higher demand in Europe and South America and price increases on certain products, partially offset by lower demand in Asia.

Global Off-Highway net sales were down 50% for the year ended December 31, 2025 compared to the year ended December 31, 2024, principally driven by lower demand from the energy, mining and construction sectors outside of North America.

Defense end market net sales were up 26% for the year ended December 31, 2025 compared to the year ended December 31, 2024, principally driven by increased demand for Tracked vehicle applications, price increases on certain products and the continued execution of our growth initiatives.

Service Parts, Support Equipment and Other end market net sales were down 3% for the year ended December 31, 2025 compared to the year ended December 31, 2024, principally driven by lower demand for aluminum die cast components and support equipment, partially offset by higher demand for service parts and price increases on certain products.

Key Components of our Results of Operations

Net sales

We generate our net sales primarily from the sale of vehicle propulsion solutions, service and component parts, support equipment, defense kits, engineering services, royalties and extended transmission coverage to a wide array of OEMs, distributors and the U.S. government. Sales are recorded in accordance with the terms of the contract, net of provisions for customer incentives and other rebates. Engineering services are recorded as net sales in accordance with the terms of the contract. The associated costs are recorded in cost of sales. We also have royalty agreements with third parties that provide net sales as a result of joint efforts in developing marketable products.

Cost of sales

Our primary components of cost of sales are purchased parts, the overhead expense related to our manufacturing operations and direct labor associated with the manufacture and assembly of vehicle propulsion solutions and parts. For the year ended December 31, 2025, direct material costs were approximately 66%, overhead costs were approximately 26% and direct labor costs were approximately 8% of total cost of sales. We are subject to changes in our cost of sales caused by movements in underlying commodity prices. We seek to

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hedge against this risk by using LTAs. See Part II, Item 7A., “Quantitative and Qualitative Disclosures about Market Risk—Commodity Price Risk” included in this Annual Report on Form 10-K.

Selling, general and administrative

The principal components of our selling, general and administrative expenses are salaries and benefits for our office personnel, advertising and promotional expenses, product warranty expense, expenses relating to certain information technology systems and amortization of our intangible assets.

Engineering — research and development

ALSN US Equity

ALSN · 10-K · period ended 2025-12-31

ITEM 1. Business

ITEM 1A. Risk Factors

ITEM 1B. UNRESOLVED STAFF COMMENTS

ITEM 1C. CYBERSECURITY

ITEM 2. PROPERTIES

ITEM 3. LEGAL PROCEEDINGS

ITEM 4. MINE SAFETY DISCLOSURES

ITEM 5. Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities

ITEM 6. [RESERVED]

ITEM 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations

ALSN US Equity☆

ALSN · 10-K · period ended 2025-12-31

ITEM 1. Business

ITEM 1A. Risk Factors

ITEM 1B. UNRESOLVED STAFF COMMENTS

ITEM 1C. CYBERSECURITY

ITEM 2. PROPERTIES

ITEM 3. LEGAL PROCEEDINGS

ITEM 4. MINE SAFETY DISCLOSURES

ITEM 5. Market for Registrant’s Common Equity, Related Stockholder Matters and Issuer Purchases of Equity Securities

ITEM 6. [RESERVED]

ITEM 7. Management’s Discussion and Analysis of Financial Condition and Results of Operations

ALSN US Equity