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

You should read the following discussion and analysis of financial condition and results of operations together with our consolidated financial statements and related notes included elsewhere in this Annual Report on Form 10-K. This discussion and other parts of this Annual Report on Form 10-K contain forward-looking statements that involve risk and uncertainties, such as statements of our plans, objectives, expectations and intentions. Our actual results, performance or achievements could differ materially from any future results, performance or achievements discussed in these forward-looking statements. Factors that could cause or contribute to such differences include, but are not limited to, those discussed under the heading “Special Note Regarding Forward-Looking Statements” and “Risk Factors.”

The following generally compares our results of operations for the years ended December 31, 2024 and 2023. A detailed discussion comparing our results of operations for the years ended December 31, 2023 and 2022 can be found in Part II, Item 7, “Management’s Discussion and Analysis of Financial Condition and Results of Operations” of our Annual Report on Form 10-K for the year ended December 31, 2023 filed with the SEC on February 28, 2024.

Overview

Castle Biosciences is a molecular diagnostics company offering innovative test solutions to aid clinicians in the diagnosis and treatment of dermatologic cancers, Barrett’s esophagus (“BE”), uveal melanoma (“UM”), and in the treatment of mental health conditions.

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Our Test Portfolio

We currently offer five commercially available proprietary multi-analyte assays with algorithmic analysis (“MAAA”) tests for use in the fields of dermatology, gastroenterology and ophthalmology. We also offer a proprietary a pharmacogenomic (“PGx”) test to guide optimal drug treatment for patients diagnosed with depression, anxiety and other mental health conditions.

Currently, our revenue is primarily generated by our DecisionDx-Melanoma risk stratification test for cutaneous melanoma (“CM”) and our DecisionDx-SCC risk stratification test for cutaneous squamous cell carcinoma (“SCC”), which is supplemented by revenue generated from our TissueCypher risk stratification test for BE and our DecisionDx-UM risk stratification test for UM.

All five of our MAAA tests have been granted Advanced Diagnostic Laboratory Test (“ADLT”) status by the Centers for Medicare and Medicaid (“CMS”) which means each test has demonstrated that (i) when combined with an empirically derived algorithm, it yields a result that predicts the probability a specific individual patient will develop a certain condition or conditions, or will respond to a particular therapy or therapies; and (ii) it provides new clinical diagnostic information that cannot be obtained from any other test or combination of tests. We believe this designation not only demonstrates our focus on developing and validating innovative tests but also enables our Medicare reimbursement rate to be set, over the long term, by the median private payor rate, which we believe provides a fair exchange of value. Further information about Medicare coverage and ADLT status with respect to each of our tests is set forth below.

Test Overview

Our Dermatology Tests

DecisionDx-Melanoma is our proprietary risk stratification gene expression profile (“GEP”) test that predicts the risk of metastasis or recurrence, including a positive sentinel lymph node, for patients diagnosed with invasive CM. In a typical year, we estimate approximately 130,000 patients are diagnosed with invasive CM in the United States, representing an estimated U.S. total addressable market (“TAM”) of approximately $540 million. We estimate that approximately 50% of patients diagnosed with CM are 65 years of age or older.

DecisionDx‐SCC is our proprietary GEP test for use in patients with SCC, with one or more risk factors (also referred to as “high-risk” SCC) that both predicts the risk of metastasis as well as response to adjuvant radiation therapy. We estimate 20% of SCC, or 200,000 annually in the United States, are classified as high risk, representing an estimated U.S. TAM of approximately $820 million.

MyPath Melanoma is our proprietary GEP test for use in patients with a melanocytic lesion and uncertainty related to the malignancy of the lesion. We estimate that approximately 300,000 patients each year present with a diagnostically ambiguous lesion, representing an estimated U.S. TAM of approximately $600 million. We began offering MyPath Melanoma following our acquisition of the Myriad MyPath Laboratory in May 2021 at which point we offered both our MyPath Melanoma test and our DiffDx-Melanoma test under an offering that we referred to as our Diagnostic GEP offering. However, following an internal assessment of the clinical value of offering both tests, we made the decision to suspend the clinical offering of DiffDx-Melanoma in February 2023 and now the focus of this offering is MyPath Melanoma.

Our Gastroenterology Test

TissueCypher is our proprietary risk stratification spatial-omics test designed to predict future development of progression of high-grade dysplasia (“HGD”) and/or esophageal cancer in patients with non-dysplastic (“ND”), indefinite dysplasia (“IND”) or low-grade dysplasia (“LGD”) BE. We estimate a U.S. TAM of approximately $1 billion.

Our Ophthalmology Test

DecisionDx-UM is a proprietary, risk stratification GEP test that predicts the risk of metastasis for patients with UM. We believe DecisionDx-UM is the standard of care in the management of newly diagnosed UM in the majority of ocular oncology practices in the United States. We estimate a U.S. TAM of approximately $10 million.

Our Mental Health Test

IDgenetix is a PGx test that guides personalized mental health medication selection and management for patients with depression, anxiety and other mental health conditions.

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Commercial Expansion Efforts

During the year ended December 31, 2023, we expanded our dermatologic and gastrointestinal commercial sales forces through territory and headcount expansions with focus being on our dermatology and gastroenterology teams.

During the year ended December 31, 2024, we further expanded our dermatology and gastroenterology teams. In late 2024, we changed our commercial strategy for our IDgenetix test, shifting resources to inside sales and non-personal promotion.

We will continue to assess market response in determining further commercial expansions and commercial team structure.

Reimbursement

The primary source of revenue for our products is reimbursement from third-party payors, which includes government payors, such as Medicare, and commercial payors, such as insurance companies. Achieving broad coverage and reimbursement of our current products by third-party payors and continued Medicare coverage are key components of our financial success.

We bill third-party payors and patients for the tests we perform. We have received Medicare coverage for our DecisionDx-Melanoma, DecisionDx-SCC, TissueCypher, MyPath Melanoma, DecisionDx-UM and IDgenetix tests which meet certain criteria for Medicare and Medicare Advantage beneficiaries.

The Medicare rates discussed below are prior to giving effect to applicable sequestration in effect from time to time as described in further detail under "Government Regulation and Product Approval—Healthcare Reform" included in Item 1, Business, of this Annual Report on Form 10-K.

DecisionDx-Melanoma

DecisionDx-Melanoma tests are processed from our Phoenix laboratory and since the second quarter of 2022, have been covered under “foundational” local coverage determinations (“LCD” or “LCDs”) finalized by Medicare Administrative Contractors (“MACs”) Palmetto and Noridian.

DecisionDx-Melanoma has met ADLT status, as determined by the CMS, since 2019. Since 2022, the rate for DecisionDx-Melanoma is set annually based upon the median private payor rate for the first half of the second preceding calendar year. For example, the rate for 2023 was set using median private payor rate data from January 1, 2021 to June 30, 2021. Our rate for 2022, 2023 and 2024 was $7,193 per test. Our rate for 2025 is $7,193 per test.

DecisionDx‐SCC

We issue our DecisionDx-SCC tests from our Pittsburgh and Phoenix labs, with a majority of tests being issued from our Pittsburgh lab. Palmetto’s MolDX program oversees MAAA tests that are reported from our Phoenix laboratory and Noridian is the MAC responsible for administering claims for test reports issued by our Phoenix laboratory.

In the second quarter of 2022, following the completion of a requested medical review and pricing of our DecisionDx-SCC test by Novitas, we obtained a PLA code and began receiving reimbursement from Novitas for DecisionDx-SCC at a rate of $3,873 per test.

On July 4, 2024, Palmetto and Noridian finalized an LCD recommending no coverage for DecisionDx-SCC with an effective date of August 18, 2024. On January 9, 2025, Novitas finalized an oncology biomarker LCD that will become effective on April 24, 2025. If the LCD becomes effective as is, then we would anticipate not receiving Medicare reimbursement for DecisionDx-SCC tests performed on or after April 24, 2025.

DecisionDx-SCC was reimbursed at a rate of $3,873 per test under a Proprietary Laboratory Analyses (“PLA”) code from second quarter of 2022 through June 30, 2023 when CMS determined DecisionDx-SCC meets the criteria for “new ADLT” status. ADLT status determines the process by which the rate is set and is not an indication of Medicare coverage. Effective July 1, 2023 and through March 31, 2024, CMS set the initial period rate equal to the list price of $8,500 per test. Effective April 1, 2024 and through December 31, 2025, the published Clinical Laboratory Fee Schedule (“CLFS”) rate for DecisionDx-SCC will be based on the median private payor rates received between July 1, 2023 and November 30, 2023. We submitted the median private payor data to CMS during the data reporting period in December 2023. Effective April 1, 2024, the updated CLFS rate will continue at $8,500 through December 31, 2025. Future rates will be set annually based upon the median private payor rate for the first half of the second preceding calendar year.

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TissueCypher

Most of our TissueCypher tests are processed in our Pittsburgh laboratory under the Medicare jurisdiction managed by Novitas.

On March 24, 2022, CMS determined that TissueCypher meets the criteria for “new ADLT” status. ADLT status exempts TissueCypher from what is called the “14-day rule,” which simplifies the billing process for Medicare patients. Effective January 1, 2023, the published CLFS rate for TissueCypher was set at $4,950 per test, which will remain effective through December 31, 2024. This rate is based on the median private payor rates received between April 1, 2022 and August 31, 2022. Thereafter, the rate will be set annually based upon the median private payor rate for the first half of the second preceding calendar year. Our 2025 rate will continue to be $4,950 per test based on the median private payor rate data from January 1, 2023 to June 30, 2023.

MyPath Melanoma and DiffDx-Melanoma

MyPath Melanoma was covered under a test-specific LCD policy through Noridian that became effective in June 2019. Effective August 6, 2023, Palmetto and Noridian issued LCDs that converted the test-specific MyPath Melanoma LCD to a “foundational” LCD and provided coverage for both MyPath Melanoma and DiffDx-Melanoma.

MyPath Melanoma was approved as a “new ADLT” in September 2019. The rate for our MyPath Melanoma test is set annually based upon the median private payor rate for the first half of the second preceding calendar year. For example, the rate for 2024 was set using median private payor rate data from January 1, 2022 to June 30, 2022. Our rates for 2022, 2023, and 2024 were $1,950 per test, $1,755 per test, and $1,950 per test, respectively. Our rate for 2025 is $1,950 per test.

In the second quarter of 2022, we obtained a PLA code for DiffDx-Melanoma. In 2023, DiffDx-Melanoma went through the CMS gapfill process which concluded in September 2023 with CMS posting a final MAC-specific gapfill rate of $1,950 per test. Our rate for 2024 was $1,950 per test and will continue to be $1,950 per test in 2025.

Diagnostic GEP Offering

Our Diagnostic GEP offering included MyPath Melanoma and DiffDx-Melanoma. We began offering MyPath Melanoma following our acquisition of the Myriad MyPath Laboratory on May 28, 2021. Our internal data indicates that we have improved the technical performance of MyPath Melanoma and that it is comparable to the technical performance of DiffDx-Melanoma. As such, following an internal assessment of the clinical value of offering both tests, we made the decision to suspend the clinical offering of DiffDx-Melanoma in February 2023.

DecisionDx-UM

DecisionDx-UM tests are processed from our Phoenix laboratory and are covered under LCDs finalized by MAC administrators Palmetto and Noridian in July 2017.

DecisionDx-UM has met the criteria of “existing advanced diagnostic laboratory test” status, also referred to as “existing ADLT” status, as determined by the CMS, since May 2019. Our rate is set annually based upon the median private payor rate for the first half of the second preceding calendar year. For example, the rate for 2024 was set using median private payor rate data from January 1, 2022 to June 30, 2022. Our rate for 2022, 2023 and 2024 was $7,776 per test. Our 2025 rate is $7,776 per test.

IDgenetix

IDgenetix is currently covered under a Noridian LCD policy and accompanying billing and coding article developed by MolDX.

Our IDgenetix multi-gene panel was reimbursed by Medicare at approximately $1,500 per test from April 2022 through February 2023, when MolDX notified us that as part of its annual Current Procedural Terminology (“CPT”) code updates, IDgenetix should shift billing to a different generic gene sequencing CPT code (the “New CPT Code”) and continue using the IDgenetix Z-Code beginning in March 2023. The New CPT Code was set at $917 per test while the test went through CMS’s Gapfill pricing process. We believed the new CPT Code, in conjunction with the IDgenetix Z-Code, did not describe all of the components of the IDgenetix test and thus, was not appropriate for IDgenetix. We subsequently obtained a test-specific PLA CPT code which became effective October 1, 2023. In November 2023, CMS posted its final CLFS determination which crosswalks our PLA CPT code to an existing PLA code at a rate of $1,336 per test effective January 1, 2024. Our reimbursement rate for 2024 was $1,336 per test, and our rate will continue to be $1,336 per test in 2025.

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Government Regulation and Oversight of Laboratory Developed Tests

On May 6, 2024, the U.S. Food and Drug Administration (“FDA”) published a final rule on the regulation of LDTs which amends the FDA's regulations to make explicit that LDT's are devices under the FD&C Act. The FDA issued a policy to phaseout, over the course of four years, its general enforcement discretion approach to LDTs and also issued targeted enforcement discretion policies for certain categories of LDTs. The FDA is continuing enforcement discretion for currently marketed tests offered as LDTs (that were first marketed before May 6, 2024) that are approved by NYSDOH. Our proprietary tests, outlined above, are all NYSDOH approved. We believe this final ruling will have no material impact on our existing test offerings given all of our tests were marketed before May 6, 2024.

Delivered Test Reports

The number of test reports we deliver is a key indicator that we use to assess our business. A test report is generated when we receive a sample in our laboratory, and then the relevant test information is entered into our Laboratory Information Management System, the laboratory portion of the test is performed, including proprietary algorithmic analysis of the combined biomarkers and a report is then delivered to the clinician who ordered the test.

The number of test reports delivered by us during the years ended December 31, 2024 and 2023 are presented in the table below:

Proprietary Dermatologic GEP Tests

(1)Our GEP offering included our MyPath Melanoma and DiffDx-Melanoma until we suspended our DiffDx-Melanoma in February 2023. We continue to offer our MyPath Melanoma test.

(2)We temporarily paused accepting additional orders in July 2023 and resumed accepting new orders in a phased approach in September 2023. We completed processing of our pre-existing backlog orders in October 2023 and continue to accept new orders as of December 31, 2023.

(3)We began offering the IDgenetix test in April 2022, following our acquisition of AltheaDx.

For the years ended December 31, 2024 and 2023, our dermatologic test report volume increased by 15.5% and 30.5%, respectively, largely driven by continued growth from our DecisionDx-Melanoma and DecisionDx-SCC tests. Increases from our other tests (non-dermatologic), primarily IDgenetix and TissueCypher, also contributed to the overall volume increase. For a discussion of how we recognize revenue derived from our tests, refer to “Net Revenues” under “Components of Results of Operations” below.

In August 2024, we amended our Pittsburgh commercial real estate lease to add 23,821 square feet to our existing facilities, most of which will be used as dedicated lab space for processing our TissueCypher test. As of December 31, 2024, substantially all leasehold improvements for this added space were complete and the added

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lab space was ready for use. We expect the additional space will allow us to continue developing our business through our TissueCypher product line.

For our DecisionDx-SCC product line, we continue to see opportunities for leverage, where many of the clinicians ordering our DecisionDx-Melanoma are the same clinicians who order our DecisionDx-SCC test. For both years ended December 31, 2024 and 2023, approximately 78% of all clinicians ordering DecisionDx-SCC had also ordered our DecisionDx-Melanoma test during that same period.

Information About Certain Metrics

The following provides additional information about certain metrics we have disclosed in this Management’s Discussion and Analysis of Financial Condition and Results of Operations.

Test Reports Delivered

Test reports delivered represent the number of completed test reports delivered by us during the reporting period indicated. The period in which a test report is delivered does not necessarily correspond with the period in which the related revenue, if any, is recognized, due to the timing and amount of adjustments for variable consideration under Accounting Standards Codification (‘‘ASC’’) Topic 606, Revenue from Contracts with Customers (“ASC 606”). We use this metric to evaluate the growth in adoption of our tests and to measure against our internal performance objectives. We believe this metric is useful to investors in evaluating the volume of our business activity from period-to-period that may not be discernible from our reported revenues under ASC 606.

Other Events

Impact of Macroeconomic Conditions

Macroeconomic conditions, including uncertainties associated with the Israel-Hamas war, the ongoing conflict between Ukraine and Russia, economic slowdowns, public health crises, labor shortages, recessions or market corrections, supply chain disruptions, inflation and monetary policy shifts, liquidity concerns at, and failures of, banks and other financial institutions or other disruptions in the banking system or financing markets, higher interest rates and financial and credit market fluctuations, volatility in the capital markets or other evolving macroeconomic developments, continue to have direct and indirect impacts on our business and could in the future materially impact our results of operations and financial condition. We continue to actively monitor the impact of these macroeconomic factors on our results of operations, financial condition and cash flows. The extent of the impact of these factors on our operational performance and financial condition, including our ability to execute our business strategies and initiatives in the expected timeframe, will depend on future developments, which are uncertain and cannot be predicted; however, any continued or renewed disruption resulting from these factors could negatively impact our business.

Our Financial Results

Our net income (loss) may fluctuate significantly from period to period, depending on the timing of our planned development activities, the growth of our sales and marketing activities and the timing of revenue recognition under ASC 606. We expect our expenses will increase substantially over time as we:

•execute clinical studies to generate evidence supporting our current and future product candidates;

•execute our commercialization strategy for our current and future commercial products;

•continue our ongoing and planned development of new products in our pipeline;

•seek to discover and develop additional product candidates;

•hire additional scientific and research and development staff;

•add additional operational, financial and management information systems and personnel; and

•make additional capital expenditures to support business growth and sustain existing operations.

Factors Affecting Our Performance

We believe there are several important factors that have impacted, and that we expect will continue to impact, our operating performance and results of operations, including:

•Report volume. We believe that the number of reports we deliver to clinicians is an important indicator of the growth of adoption among the healthcare provider community. Our revenue and costs are affected by the volume of testing and mix of customers. Our performance depends on our ability to retain and broaden

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adoption with existing prescribing clinicians, as well as attract new clinicians. Our report volume could be negatively impacted by developments related to evolving macroeconomic developments, as discussed above.

•Reimbursement. We believe that expanding reimbursement is an important indicator of the value of our products. Payors require extensive evidence of clinical utility, clinical validity, patient outcomes and health economic benefits in order to provide reimbursement for diagnostic products. Our revenue depends on our ability to demonstrate the value of our products to these payors.

•Gross margin. We believe that our gross margin is an important indicator of the operating performance of our business. Higher gross margins reflect the average selling price of our tests, as well as the operating efficiency of our laboratory operations.

•Expansion of our sales force and marketing programs. We believe the expansion of our direct sales force and marketing organization to educate clinicians and pathologists on the value of our molecular testing products will significantly impact our performance.

•Integrating acquisitions. Revenue growth, operational results and advances to our business strategy depend on our ability to integrate any acquisitions into our existing business and effectively scale their operations. The integration of acquired assets may impact our revenue growth, increase the cost of operations or may require management resources that otherwise would be available for ongoing development of our existing business.

•New product development. A significant aspect of our business is our investment in research and development activities, including activities related to the development of new products. In addition to the development of new product candidates, we believe these studies are critical to gaining clinician adoption of new products and driving favorable coverage decisions by payors for such products.

Components of the Results of Operations

Net Revenues

We generate revenues from the sale of our products. Currently, our revenues are primarily derived from the sale of DecisionDx-Melanoma, DecisionDx-SCC, TissueCypher and DecisionDx-UM. We bill third-party payors and patients for the tests we perform.

Under ASC 606, we recognize revenue at the amount we expect to be entitled, subject to a constraint for variable consideration, in the period in which our tests are delivered to the treating clinicians. We have determined that our contracts contain variable consideration under ASC 606 because the amounts paid by third-party payors may be paid at less than our standard rates or not paid at all, with such differences considered implicit price concessions. Variable consideration is recognized only to the extent it is probable that a significant reversal of revenue will not occur in future periods when the uncertainties are resolved. Variable consideration is evaluated each reporting period and adjustments are recorded as increases or decreases in revenues. Variable consideration for Medicare claims that are not covered by Medicare, including those claims undergoing appeal, is deemed to be fully constrained due to factors outside our influence (e.g., judgment or actions of third parties) and the uncertainty of the amount to be received is not expected to be resolved for a long period of time. For these fully constrained claims, we generally recognize revenue in the period the uncertainty is favorably resolved, if at all. Due to potential future changes in Medicare coverage policies and appeal cycles, insurance coverage policies, contractual rates and other trends in the reimbursement of our tests, our revenues may fluctuate significantly from period to period. Our ability to recognize revenue for a test is dependent on the development of reimbursement experience and obtaining coverage decisions. For tests with limited reimbursement experience or no coverage, we recognize revenues on the basis of actual cash collections.

Our ability to increase our revenues will depend on our ability to further penetrate our target markets, and, in particular, generate sales through our direct sales force, maintain Medicare coverage for our currently marketed products, develop and commercialize additional tests, including through acquisitions, obtain reimbursement from additional third-party payors and increase our reimbursement rate for tests performed.

Cost of Sales (exclusive of amortization of acquired intangible assets)

The components of our cost of sales are material and service costs associated with testing samples, personnel costs (including salaries, bonuses, benefits and stock-based compensation expense), electronic medical record set up costs, order and delivery systems, shipping charges to transport samples, third-party test fees, and allocated overhead including rent, information technology costs, equipment and facilities depreciation and utilities. Costs

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associated with testing samples are recorded when the test is processed regardless of whether and when revenues are recognized with respect to that test. As a result, our cost of sales as a percentage of revenues may vary significantly from period to period because we do not recognize all revenues in the period in which the associated costs are incurred. We expect cost of sales in absolute dollars to increase as the number of tests we perform increases. Additionally, we expect cost of sales to increase prior to our launching of new tests, or prior to our initiating significant commercial expansion efforts, as we ready our operations to support anticipated business growth. For example, prior to opening our new Pittsburgh facilities during the second quarter of 2023, we incurred additional rent expense as we readied the space for future use.

Gross margin and gross margin percentage are key indicators we use to assess our business. See the table in “—Results of Operations—Comparison of the years ended December 31, 2024 and 2023” for details.

Research and Development

Research and development expenses include costs incurred to develop our tests, collect clinical samples and conduct clinical studies to develop and support our products. These costs consist of personnel costs (including salaries, bonuses, benefits and stock-based compensation expense), prototype materials, laboratory supplies, consulting costs, regulatory costs, electronic medical records set up costs, costs associated with setting up and conducting clinical studies and allocated overhead, including rent, information technology, equipment depreciation and utilities. We expense all research and development costs in the periods in which they are incurred. We expect our research and development expenses to increase in absolute dollars as we continue to invest in research and development activities related to developing enhanced and new products.

We expect to use a portion of our cash and cash equivalents and marketable investment securities to further support and accelerate our ongoing and future clinical studies and pipeline initiatives.

Selling, General and Administrative

Selling, general and administrative (“SG&A”) expenses include executive, selling and marketing, legal, finance and accounting, human resources and billing functions. These expenses consist of personnel costs (including salaries, bonuses, benefits and stock-based compensation expense), direct marketing expenses, audit and legal expenses, consulting costs, payor outreach programs and allocated overhead, including rent, information technology, equipment depreciation, and utilities. Other administrative and professional services expenses within SG&A are expected to increase with the scale of our business, but selling and marketing-related expenses are expected to increase significantly, consistent with our growth strategy.

Amortization of Acquired Intangible Assets

Amortization of acquired intangible assets is primarily associated with developed technology obtained through acquisitions, such as our acquisitions of Cernostics in December 2021 and AltheaDx in April 2022.

Interest Income

Interest income consists primarily of earnings on cash and cash equivalents, primarily money market funds, and our short-term U.S. government obligations are a component of our marketable investment securities.

Change in Fair Value of Trading Securities

Change in fair value of trading securities is primarily attributable to unrealized gains and losses on our equity securities which we present as marketable investment securities.

Interest Expense

Interest expense is primarily attributable to long term debt and finance leases.

Income Tax Expense

Income tax expense consists primarily of income taxes related to federal and state jurisdictions in which we conduct business. We maintain a full valuation allowance for deferred tax assets including operating loss carryforwards and research and development credits and other tax credits. Our consolidated financial statements do not reflect any federal or state income tax benefits attributable to the pre-tax losses we have incurred, due to the uncertainty of realizing a benefit from those items. As of December 31, 2024, we had federal NOL carryforwards of $129.4 million, of which $52.9 million will begin to expire in 2031 if not utilized to offset federal taxable income, and $76.5 million may be carried forward indefinitely. Also, as of December 31, 2024, we also had state NOL carryforwards of $86.5 million, which begin to expire in 2028 if not utilized to offset state taxable income.

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Results of Operations

Comparison of the Years Ended December 31, 2024 and 2023

The following table summarizes our results of operations for the periods indicated (in thousands, except percentages):

Years Ended December 31, Change

OPERATING EXPENSES AND OTHER OPERATING INCOME

Changes in fair value of trading securities 555 — 555 NA

(1) NA = Not applicable

(2) NM = Not meaningful

The following table indicates the amount of stock-based compensation expense (non-cash) reflected in the line items above (in thousands):

Years Ended December 31,

The following table provides a disaggregation of net revenues by type (in thousands):

Years Ended December 31,

(1)Consists of DecisionDx-Melanoma, DecisionDx-SCC and our Diagnostic Gene Expression Profile offering (MyPath Melanoma and DiffDx-Melanoma).

(2)Consists of TissueCypher, DecisionDx-UM and IDgenetix.

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The following table presents the calculation of gross margin (in thousands, except percentages):

Years Ended December 31,

Less: Amortization of acquired intangible assets 11,106 9,013 2,093

Gross margin percentage 78.5 % 75.4 % 3.1 %

Net Revenues

Net revenues for the year ended December 31, 2024 increased by $112.3 million, or 51.1%, to $332.1 million compared to the year ended December 31, 2023 due to a $73.6 million increase in revenue from our dermatologic tests and a $38.7 million increase in revenue from our non-dermatologic tests.

The $73.6 million increase in net revenues for our dermatologic tests was primarily attributable to our DecisionDx-SCC test, which was due to higher test report volumes and a higher realized average selling price (“ASP”), as well as our DecisionDx-Melanoma test which had higher test report volumes and a slightly higher realized ASP. For the year ended December 31, 2024 compared to the year ended December 31, 2023, test report volumes for our DecisionDx-SCC and DecisionDx-Melanoma tests increased by 42.9% and 8.0%, respectively. Increases in realized ASP for our DecisionDx-SCC test were primarily attributable to receiving Medicare reimbursement at a higher rate beginning in July 2023.

The $38.7 million increase in net revenues from our non-dermatologic tests was largely attributable to a 130.3% increase in test report volumes for our TissueCypher test, and, to a lesser extent, to our IDgenetix test which also had higher test report volumes. Increases in our TissueCypher test report volumes reflect growth through our sales force efforts. Net revenue from our non-dermatologic tests as a percentage of total net revenue increased from 16.6% for the year ended December 31, 2023 to 22.6% for the year ended December 31, 2024.

Cost of Sales (exclusive of amortization of acquired intangible assets)

Cost of sales (exclusive of amortization of acquired intangible assets) for the year ended December 31, 2024 increased by $15.2 million, or 33.8%, compared to the year ended December 31, 2023, primarily due to higher personnel costs and higher expense for supplies and depreciation. Increases in personnel costs reflect higher headcount to support business growth in response to growing test report volumes, commencement operations at our new Pittsburgh laboratory in the second quarter of 2023, as well as merit and annual inflationary wage adjustment for existing employees. Higher expense for supplies and lab services also reflects higher test report volumes.

Due to the nature of our business, a significant portion of our cost of sales expenses represents fixed costs associated with our testing operations. Accordingly, our cost of sales expense will not necessarily increase or decrease commensurately with the change in net revenues from period to period. We expect our cost of sales expenses (exclusive of amortization of acquired intangible assets) to continue to increase in future periods as we hire additional laboratory personnel and related resources to support expected operational growth and higher test volumes.

Gross Margin

Our gross margin percentage was 78.5% for the year ended December 31, 2024, compared to 75.4% the same period in 2023. The increase was primarily due to higher revenues, partially offset by higher personnel costs, higher expense for supplies and depreciation and higher expense incurred through our expanded laboratory capacity and higher test report volumes.

Research and Development

Research and development expenses decreased by $1.6 million, or 2.9%, for the year ended December 31, 2024, compared to the year ended December 31, 2023, primarily reflecting lower clinical studies costs, lower organizational development costs, and lower expense for laboratory supplies, partially offset by higher personnel costs.

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We expect to continue incurring research and development expenses through our continued investments in our ongoing pipeline initiatives and as we seek opportunities to build evidentiary support and new tests where commercial opportunities exist.

Selling, General and Administrative

The following table provides a breakdown of SG&A expenses (in thousands):

Years Ended December 31,

Sales and marketing expenses increased by $9.8 million, or 8.6%, for the year ended December 31, 2024 compared to the year ended December 31, 2023. The increase is primarily due to higher personnel costs, higher sales related travel expense, and higher incurred organizational and business development activities. Increases in personnel costs reflect a higher headcount as well as merit and annual inflationary wage adjustment for existing employees. The higher test report volumes are a result of our continued investments in human capital for our sales organization. Stock based compensation expense included in sales and marketing expense was $17.3 million for the year ended December 31, 2024, compared to $18.3 million for the year ended December 31, 2023.

General and administrative expenses increased by $10.1 million, or 15.2%, for the year ended December 31, 2024, compared to the year ended December 31, 2023. The increase is primarily due to higher personnel costs, professional fees and information technology-related cost expenses. Increases in personnel costs reflect headcount expansions in our administrative support functions as well as merit and annual inflationary wage adjustment for existing employees. Stock-based compensation expense included in general and administrative expense was $17.8 million for the year ended December 31, 2024, compared to $17.9 million for the year ended December 31, 2023.

Amortization of Acquired Intangible Assets

Amortization expense increased by approximately $2.1 million for the year ended December 31, 2024, compared to the year ended December 31, 2023, due primarily to our revision of the estimated useful life of our IDgenetix developed technology intangible assets in December 2024, where we determined the estimated remaining useful life was 13 months, with the useful life now expected to end on December 31, 2025. We expect amortization expense will increase by approximately $24.3 million for the year ended December 31, 2025 due to this change in estimate.

Interest Income

Interest income increased by $2.3 million for the year ended December 31, 2024, compared to the year ended December 31, 2023, primarily as a result of higher balances held in marketable investment securities.

Changes in Fair Value of Trading Securities

The change in fair value of trading securities increased by $0.6 million for the year ended December 31, 2024, compared to the year ended December 31, 2023, and was entirely associated with our investments in equity securities in October 2024 where we had no such investments during the comparative period.

Interest Expense

Interest expense increased by $0.6 million for the year ended December 31, 2024, compared to the year ended December 31, 2023, primarily due to interest incurred on our long-term debt where we had no debt outstanding during the comparative period.

Income Tax Expense

Income tax expense increased by $3.2 million for the year ended December 31, 2024, compared to the year ended December 31, 2023, primarily as a result of state income taxes and the realization of pre-tax income during the year ended December 31, 2024 and a net operating loss in the year ended December 31, 2023.

Stock-Based Compensation Expense

Stock-based compensation expense, which is allocated among cost of sales, research and development expense and SG&A expense, totaled $50.3 million for the year ended December 31, 2024 compared to $51.2 million for the

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year ended December 31, 2023. We expect material increases in stock-based compensation expense in future periods, attributable to both existing awards outstanding and anticipated additional grants to our current and future employees. We had 761 employees as of December 31, 2024, compared to 610 as of December 31, 2023. As of December 31, 2024, total unrecognized stock-based compensation cost related to outstanding awards was $71.1 million, which is expected to be recognized over a weighted-average period of 2.2 years.

Liquidity and Capital Resources

Sources of Liquidity

Our principal sources of liquidity are our cash and cash equivalents, marketable investment securities, and cash generated from the sale of our products and our line-of-credit under the 2024 LSA. All of our marketable investment securities are considered investment grade, are readily available for use in current operations and have contractual maturities of one year or less. As of December 31, 2024 and 2023, we had marketable investment securities of $173.4 million and $144.3 million, respectively, and cash and cash equivalents of $119.7 million and $98.8 million, respectively. Additionally, as of December 31, 2024, we had a $25.0 million credit line available under the 2024 LSA.

Our liquidity has been primarily derived from the revenue generated from the sale of our products, and proceeds from our IPO in July 2019 and our follow-on public offerings of common stock in June and December of 2020. We believe that our existing cash and cash equivalents, marketable investment securities and anticipated cash generated from sales of our products will be sufficient to fund our operations for at least the next 12 months. However, we have based these estimates on assumptions that may prove to be wrong, and could result in us depleting our capital resources sooner than expected.

As mentioned above, we expect to use a portion of our cash and cash equivalents and marketable investment securities to further support and accelerate our research and development activities, including the clinical studies noted above in “—Components of the Results of Operations—Research and Development.”

Material Cash Requirements

Our primary uses of capital are, and we expect will continue to be, compensation and related expenses, clinical research and development services, laboratory operations, equipment and related supplies, legal and other regulatory expenses, general administrative costs and, from time to time, expansion of our laboratory and office facilities in support of our growth, such as the construction of our future corporate headquarters. We anticipate that a substantial portion of our cash requirements in the foreseeable future will relate to the further commercialization of our currently marketed products, the development of our future product candidates in our pipeline and the potential commercialization of these pipeline products, should their development be successful and the construction of our future corporate headquarters.

In July 2023, we entered into a definitive agreement to purchase a plot of land located in Friendswood, Texas for a purchase price of $7.6 million, subject to certain adjustments, for the purpose of developing a commercial office building where our future corporate headquarters will be located. In February 2024, we closed on the purchase of the land for cash consideration of $7.2 million. The development project will include a four-story building, which will encompass approximately 80,000 square feet of Class A office space. Construction began in May 2024 and is expected to continue through early 2026, at which time the building is expected to be ready for occupancy and use. Over the duration of this project, we expect to make significant capital expenditures in the form of payments to the developer under a percentage of completion basis. As of December 31, 2024, the development project is expected to cost a total of approximately $42.3 million. During the year ended December 31, 2024, we made $9.3 million in capital expenditures for this development project. We intend to use the proceeds from the 2024 Term Loan (as defined below), the 2024 Credit Line (as defined below) and our existing cash and cash equivalents to pay for this project.

Since our inception, we have generally incurred significant losses and negative operating cash flows, and we have relied heavily on proceeds from our financing activities to fund capital expenditures, business expansion campaigns, and to offset operating deficits. For the year ended December 31, 2024, we recognized net income of $18.2 million and had positive operating cash flow of $64.9 million, though we may be unable to sustain profitability and positive cash flows in future periods. Collections on Medicare claims for our DecisionDx-SCC test represented a significant portion of our 2024 operating cash flows. We will lose Medicare coverage for our DecisionDx-SCC test in April 2025 and decreases in revenues and cash inflows from this test are expected to follow. Our ability to maintain profitability will heavily depend on us maintaining Medicare coverage for our currently marketed products, on the successful commercialization of the products we plan to launch in the future, and our ability to manage operating expenses. We expect to incur additional expenses in the future as we invest in the commercialization of our existing products and the development and commercialization of our current pipeline products and future product candidates. We

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believe that our existing cash and cash equivalents, marketable investment securities and anticipated cash generated from the sale of our commercial products will be sufficient to fund our operations for at least the next 12 months. We believe we will meet longer-term expected cash requirements and obligations through a combination of existing cash and cash equivalents, marketable investment securities and anticipated cash generated from sales of our products and issuances of equity securities or debt offerings. However, we have based these estimates on assumptions that may prove to be wrong, and we could utilize our available capital resources sooner than we expect. There are numerous risks and uncertainties associated with developing genomic tests, including, among others, the uncertainty of:

•successful commencement and completion of clinical study protocols;

•successful identification and acquisition of tissue samples;

•the development and validation of genomic classifiers; and

•acceptance of new genomic tests by clinicians, patients and third-party payors including competitor actions.

Because of the numerous risks and uncertainties associated with research, development and commercialization of product candidates, we are unable to estimate our exact working capital requirements. Our future funding requirements will depend on and could increase significantly as a result of, many factors, including those listed above as well as those listed in Part I, Item 1A., “Risk Factors” in this Annual Report on Form 10-K and in our other filings with the SEC.

In the event additional funding is required, we expect that we would use a combination of equity and debt financings, which may not be available to us when needed, on terms that we deem to be favorable or at all. To the extent that we raise additional capital through the sale of equity or convertible debt securities, the ownership interest of our stockholders will be diluted, and the terms of these securities may include liquidation or other preferences that adversely affect the rights of common stockholders. Debt financing and preferred equity financing, if available, may involve agreements that include covenants limiting or restricting our ability to take specific actions, such as incurring additional debt, making acquisitions or capital expenditures or declaring dividends. Any disruptions to, or volatility in, the credit and financial markets or any deterioration in overall economic conditions may make any necessary debt or equity financing more difficult to obtain, more costly and/or more dilutive. If we are unable to raise additional funds through debt or equity financing or other arrangements when needed, we may be required to delay, limit, reduce or terminate our product discovery and development activities or future commercialization efforts.

Long-Term Debt

We had no debt as of December 31, 2023. Our long-term debt as of December 31, 2024 is presented in the table below (in thousands):

Unamortized discount (177)

Less: Current portion of long-term debt (278)

Total long-term debt $ 9,745

2024 Loan and Security Agreement

On March 26, 2024 (the ‘‘Closing Date’’), we entered into the 2024 LSA, by and between the Company, its wholly owned subsidiary, Castle Narnia Real Estate Holding 1, LLC and Silicon Valley Bank, a division of First-Citizens Bank & Trust Company (the “Lender’’). The 2024 LSA provides for (i) on the Closing Date, $10.0 million aggregate principal amount of Term Loans (the “2024 Term Loan,” as more fully discussed in the ‘‘2024 Term Loan’’ section below), and (ii) from the Closing Date until March 31, 2025, an additional line of credit of $25.0 million with the same interest rate and maturity as the term debt available (the “2024 Credit Line,” as more fully discussed in ‘‘2024 Credit Line’’ below) at our option.

The obligations under the 2024 LSA are secured by substantially all of our assets, excluding intellectual property, the real property held by the Company, and are subject to certain other exceptions and limitations. We have the right to prepay the 2024 LSA in whole, subject to a prepayment fee of approximately 1.50% if paid prior to March 26, 2026. Amounts repaid under the 2024 LSA may not be reborrowed.

In addition, the 2024 LSA contains customary conditions of borrowing, events of default and covenants, including covenants that restrict our ability to dispose of assets, merge with or acquire other entities, incur indebtedness and make distributions to holders of our capital stock. Should an event of default occur, including the occurrence of a

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material adverse change, we could be liable for immediate repayment of all obligations under the 2024 LSA. Should we seek to amend the terms of the 2024 LSA, the consent of the Lender would be required. As of December 31, 2024, we were in compliance with these covenants.

The 2024 LSA bears interest at a floating rate equal to the greater of (a) the WSJ Prime Rate plus 0.25% or (b) 6.00% per annum. The Term Loans are interest only from the Closing Date through November 30, 2025, which may be extended at our option through November 30, 2026 as long as no event of default under the 2024 LSA has occurred. After the end of the interest only period, we are required to pay equal monthly installments of principal through the maturity date of November 1, 2028.

We are also obligated to make an additional final payment of 2.00% of the aggregate original principal amounts of Term Loans advanced by the Lender, due at the earlier of the maturity date or date the Term Loans are repaid in full.

2024 Term Loan

On the Closing Date, we drew $10.0 million in Term Loans under the terms and provisions of the 2024 LSA. We are obligated to make a final payment of $0.2 million under the terms of the 2024 LSA final payment provisions. A discount on debt equal to this obligation was recorded on the draw date and is being amortized as additional interest expense using the effective interest method over the term of the debt. As of December 31, 2024, the effective interest rate for all outstanding debt under the 2024 Term Loan was 8.19%.

2024 Credit Line

We have a $25.0 million line of credit under the terms and provisions of the 2024 LSA available from the Closing Date until March 31, 2025. Amounts repaid under the 2024 Credit Line may not be reborrowed. As of December 31, 2024, no draws had been made on the 2024 Credit Line.

Leases

We have entered into various operating and finance leases, which are primarily associated with our laboratory facilities and office space.

Total undiscounted future minimum payment obligations under our operating leases and finance leases as of December 31, 2024 totaled approximately $23.3 million, of which $3.1 million is payable in 2025 and $20.2 million is payable through early 2034. The leases expire on various dates through 2034 and provide certain options to renew for additional periods.

We expect our lease obligations may increase in the future as we expand our facilities, operations and headcount in support of the anticipated growth in our portfolio of commercial products and pipeline tests. Refer to Note 11 of the consolidated financial statements for additional information on our leasing arrangements.

Cash Flows

The following table summarizes our sources and uses of cash and cash equivalents for each of the periods presented (in thousands):

Years Ended December 31,

Net cash provided by (used in) operating activities $ 64,866 $ (5,626)

Net cash used in investing activities (50,137) (16,183)

Net cash provided by (used in) financing activities 6,139 (2,298)

Net change in cash and cash equivalents 20,868 (24,107)

Cash and cash equivalents, beginning of year 98,841 122,948

Cash and cash equivalents, end of year $ 119,709 $ 98,841

Operating Activities

Net cash provided by operating activities was $64.9 million for the year ended December 31, 2024, and was primarily attributable to the net income of $18.2 million, non-cash stock-based compensation expense of $50.3 million, depreciation and amortization of $16.0 million, increases in accrued compensation of $3.6 million, increases in deferred income taxes of $1.4 million, partially offset by increases in accounts receivable of $12.6 million, increases in accretion of discounts on marketable investment securities of $6.7 million, increases in accounts payable of $4.4 million and increases in prepaid expenses and other current assets of $1.1 million.

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Net cash used in operating activities was $5.6 million for the year ended December 31, 2023, and was primarily attributable to the net loss of $57.5 million, increases in accounts receivable of $14.9 million, increases in accretion of discounts on marketable investment securities of $5.5 million and increases in inventory of $4.0 million, partially offset by non-cash stock-based compensation expense of $51.2 million, depreciation and amortization of $12.3 million, increases in accounts payable of $5.7 million, increases in accrued compensation of $4.6 million and increases in other accrued and current liabilities of $2.1 million.

The $70.5 million increase in net cash provided by operating activities for the year ended December 31, 2024 compared to the year ended December 31, 2023 is primarily due to increases in collections from customers attributable to higher net revenues partially offset by increases in operating expenditures. In part, the cash used during the year ended December 31, 2024 reflects the payment of annual cash bonuses to our employees as well as certain health care benefit payments totaling $20.8 million. In comparison, we paid $17.7 million during the same period in 2023 towards annual cash bonuses and certain health care benefits.

Investing Activities

Net cash used in investing activities was $50.1 million for the year ended December 31, 2024 and consisted primarily of purchases of marketable investment securities of $205.7 million, and purchases of property and equipment of $28.3 million, partially offset by the maturity of marketable investment securities of $183.9 million.

Net cash used in investing activities was $16.2 million for the year ended December 31, 2023 and consisted primarily of purchases of marketable investment securities of $189.1 million and purchases of property and equipment of $13.6 million, partially offset by the maturity of marketable investment securities of $186.5 million.

The $34.0 million increase in cash used in investing activities for the year ended December 31, 2024 compared to the year ended December 31, 2023 was primarily due to purchasing $16.7 million more in marketable investment securities and collecting $2.6 million fewer proceeds from maturing marketable investment securities. We also increased our purchases of property and equipment by $14.7 million for the year ended December 31, 2024 compared to the year ended December 31, 2023, primarily due to our purchase of land for cash consideration of $7.2 million on February 9, 2024 and $6.8 million in cash payments relating to the development of our future corporate headquarters.

Financing Activities

Net cash provided by financing activities was $6.1 million for the year ended December 31, 2024, and consisted primarily of $10.0 million of proceeds from issuance of long-term debt and $3.0 million of proceeds from contributions to our 2019 Employee Stock Purchase Plan (the “ESPP”) and $2.0 million of proceeds from the exercise of stock options, partially offset by the $8.8 million payment of employee taxes attributable to the vesting of RSUs.

Net cash used in financing activities was $2.3 million for the year ended December 31, 2023, and consisted primarily of payment of employees’ taxes on vested RSUs of $5.1 million, partially offset by $2.7 million of proceeds from contributions to our 2019 ESPP.

Inflation

In 2021, the rate of inflation in the United States significantly increased until the second half of 2022 when the rate began to subside. In 2023 and 2024, the inflation rate continued to subside but remained higher than rates experience between 2025 and 2020. We continue to experience inflationary pressures, primarily in increased personnel costs and price increases for certain lab supplies. We anticipate possible inflationary impacts on other cost areas in the future. The extent of any future impacts from inflation on our business and our results of operations will be dependent upon how long the elevated inflation levels persist and the extent to which the rate of inflation were to further increase, if at all, neither of which we are able to predict. If elevated levels of inflation were to persist or if the rate of inflation were to accelerate, the purchasing power of our cash and cash equivalents and marketable investment securities may be further diminished, our expenses could increase faster than anticipated and we may utilize our capital resources sooner than expected. Further, given the complexities of the reimbursement landscape in which we operate, our payors may be unwilling or unable to increase reimbursement rates to compensate for inflationary impacts. As such, the effects of inflation have had, and may continue, to adversely impact our results of operations, financial condition and cash flows.

Critical Accounting Estimates

Our consolidated financial statements are prepared in accordance with U.S. GAAP. The preparation of our consolidated financial statements and related disclosures requires us to make estimates and judgments that affect

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the reported amounts of assets, liabilities, costs and expenses, and the disclosure of contingent assets and liabilities in our consolidated financial statements. We base our estimates on historical experience, known trends and events and various other factors that we believe are reasonable under the circumstances, the results of which form the basis for making judgments about the carrying values of assets and liabilities that are not readily apparent from other sources. We evaluate our estimates and assumptions on an ongoing basis. Our actual results may differ from these estimates under different assumptions or conditions.

While our significant accounting policies are described in more detail in Note 2 to our audited consolidated financial statements, we believe that the following accounting policies are those most critical to the judgments and estimates used in the preparation of our consolidated financial statements.

Revenue Recognition

We recognize revenue in accordance with ASC 606. In accordance with ASC 606, we follow a five-step process to recognize revenues: (1) identify the contract with the customer, (2) identify the performance obligations, (3) determine the transaction price, (4) allocate the transaction price to the performance obligations and (5) recognize revenues when the performance obligations are satisfied. We have determined that we have a contract with the patient when the treating clinician orders the test. Our contracts generally contain a single performance obligation, which is the delivery of the test report, and we satisfy our performance obligation at a point-in-time upon the delivery of the test report to the treating clinician, at which point we can bill for the report. The amount of revenue recognized reflects the amount of consideration to which we expect to be entitled, or the transaction price, and considers the effects of variable consideration.

All of our revenues from contracts with customers are associated with the provision of diagnostic, prognostic and predictive testing services. Our revenues are primarily attributable to DecisionDx-Melanoma for CM and our DecisionDx-SCC test for SCC. We also provide a test for patients diagnosed with BE, the TissueCypher test, a test for patients with suspicious pigmented lesions, MyPath Melanoma and DiffDx-Melanoma, and a test for UM, DecisionDx-UM. We also began offering a PGx testing service focused on mental health, IDgenetix, following a business combination completed in April 2022.

Once we satisfy our performance obligations and bill for the service, the timing of the collection of payments may vary based on the payment practices of the third-party payor and the existence of contractually established reimbursement rates. The payments for our services are primarily made by third-party payors, including Medicare and commercial health insurance carriers. Certain contracts contain a contractual commitment of a reimbursement rate that differs from our list prices. However, absent a contractually committed reimbursement rate with a commercial carrier or governmental program, our diagnostic tests may or may not be covered by these entities’ existing reimbursement policies. In addition, patients do not enter into direct agreements with us that commit them to pay any portion of the cost of the tests in the event that their insurance provider declines to reimburse us. We may pursue, on a case-by-case basis, reimbursement from such patients in the form of co-payments and co-insurance, in accordance with the contractual obligations that we have with the insurance carrier or health plan. These situations may result in a delay in the collection of payments.

The Medicare claims that are covered are generally paid at the established rate by our Medicare contractor within 30 days from receipt. Medicare claims that were either submitted to Medicare prior to a medical review and coverage, or an LCD’s effective date, or are not covered, but meet the definition of being medically reasonable and necessary pursuant to the controlling Section 1862(a)(1)(A) of the Social Security Act may be paid upon initial claim submission or if denied for payment are generally appealed and may ultimately be paid at the first (termed “redetermination”), second (termed “reconsideration”) or third level of appeal (de novo hearing with an ALJ). A successful appeal at any of these levels results in payment.

In the absence of Medicare coverage or contractually established reimbursement rates, we have concluded that our contracts include variable consideration because the amounts paid by Medicare or commercial health insurance carriers may be paid at less than our standard rates or not paid at all, with such differences considered implicit price concessions. Variable consideration attributable to these price concessions is measured at the expected value using the “most likely amount” method under ASC 606. The amounts are estimated using historical average collection rates by test type and payor category taking into consideration the range of possible outcomes, the predictive value of our past experiences, the time period of when uncertainties expect to be resolved and the amount of consideration that is susceptible to factors outside of our influence, such as the judgment and actions of third parties. Such variable consideration is included in the transaction price only to the extent it is probable that a significant reversal in the amount of cumulative revenue recognized will not occur when the uncertainties with respect to the amount are resolved. Variable consideration may be constrained and excluded from the transaction price in situations where there is no contractually agreed upon reimbursement coverage or in the absence of a

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predictable pattern and history of collectability with a payor. Variable consideration for Medicare claims for which there are no existing positive coverage decisions, including those claims subject to approval by an ALJ at an appeal hearing, is deemed to be fully constrained due to factors outside our influence (i.e., judgment or actions of third parties) and the uncertainty of the amount to be received is not expected to be resolved for a long period of time. Variable consideration is evaluated each reporting period and adjustments are recorded as increases or decreases in revenues. Included in revenues for the years ended December 31, 2024 and 2023 were $1.8 million of net negative revenue adjustments and $4.5 million of net negative revenue adjustments, respectively, associated with changes in estimated variable consideration related to performance obligations satisfied in previous periods. These amounts include (i) adjustments for actual collections versus estimated amounts and (ii) cash collections and the related recognition of revenue in current period for tests delivered in prior periods due to the release of the constraint on variable consideration.

Stock-Based Compensation

Stock-based compensation expense for equity instruments issued to employees and non-employees, including stock options, RSUs, performance-based restricted stock units (“PSUs”) and purchase rights issued under the ESPP is measured based on the grant date fair value of the awards. For stock options and purchase rights granted under the ESPP, we estimate the grant date fair value using the Black-Scholes option-pricing valuation model. For RSUs and PSUs, we use the closing price of our common stock on the date of grant to determine the fair value. We recognize compensation costs on a straight-line basis for awards with only service conditions, which is generally the awards’ vesting period, typically four years for options and RSUs and the two-year offering period for the ESPP. PSUs vest upon the achievement of certain performance conditions and the provision of service with us through a specified period. Accruals of compensation cost for PSUs are based on the probable outcome of the performance conditions and are reassessed each reporting period. We recognize compensation cost for PSUs separately for each vesting tranche on a ratable basis over the requisite service period. The requisite service period for PSUs is based on an analysis of vesting requirements and performance conditions for the particular award. Under specific circumstances, certain employees may be eligible for accelerated vesting of a portion of their awards upon retirement, contingent upon meeting predefined criteria related to age, tenure, and notice. The determination of the requisite service period considers the employee's retirement eligibility and is reassessed at each reporting date. Forfeitures are accounted for as they occur.

Certain employees are entitled to acceleration of vesting of a portion of their awards upon retirement, subject to age, service and notice requirements. In these cases, the requisite service period takes into consideration the employee’s retirement eligibility, and is reassessed at each reporting date. For the ESPP, the requisite service period is generally the period of time from the offering date to the purchase date.

Set forth below is a description of the significant assumptions used in the option pricing model:

•Expected term. The expected term is the period of time that granted options are expected to be outstanding. For stock options, we have set the expected term using the simplified method based on the weighted average of both the period to vesting and the period to maturity for each option, as we have concluded that our stock option exercise history does not provide a reasonable basis upon which to estimate the expected term. For the ESPP, the expected term is the period of time from the offering date to the purchase date.

•Expected volatility. Previously, because of the limited period of time our stock had been traded in an active market, we calculated expected volatility by using the historical stock prices of a group of similar companies looking back over the estimated life of the option or the purchase rights under the ESPP and averaging the volatilities of these companies. In the third quarter of 2021, we adjusted this calculation to include our own stock price on a relative basis to the peer group in the calculation of expected volatility, as our common stock has now been traded in an active market for more than two years.

•Risk-free interest rate. We base the risk-free interest rate used in the Black-Scholes valuation model on the market yield in effect at the time of option grant and at the offering date for the ESPP provided from the Federal Reserve Board’s Statistical Releases and historical publications from the Treasury constant maturities rates for the equivalent remaining terms.

•Dividend yield. We have not paid, and do not have plans to pay, cash dividends. Therefore, we use an expected dividend yield of zero in the Black-Scholes option valuation model.

The fair value of our common stock is also an assumption used to determine the fair value of stock options. Prior to our IPO, the estimated fair value of our common stock had been determined by our board of directors as of the date of each award, with input from management, considering our most recently available third-party valuations of common stock and our board of directors’ assessment of additional objective and subjective factors that it believed

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were relevant and which may have changed from the date of the most recent valuation through the date of the grant, which intended all options granted to be exercisable at price per share not less than the per share fair value of our common stock underlying those options on the grant date. Subsequent to our IPO, the fair value of our common stock is the closing selling price per share of our common stock as reported on the Nasdaq Global Market on the date of grant or other relevant determination date.

The following table sets forth the assumptions used to determine the fair value of stock options:

Years Ended December 31,

Average expected term (years) 5.0 5.0 5.8

Dividend yield —% —% —%

The following table sets forth assumptions used to determine the fair value of the purchase rights issued under the ESPP:

Years Ended December 31,

Average expected term (years) 1.2 1.3 1.3

Dividend yield —% —% —%

Intangible Assets and Goodwill

Intangible assets

Our intangible assets, which are comprised primarily of acquired developed technology, are considered to be finite-lived and are amortized on a straight-line basis over their estimated useful lives. Estimating the useful lives of our intangible assets requires considerable judgment. In determining the estimated useful lives, management considers factors such as historical experience, industry and regulatory factors, competition, patent expirations and commercial plans. If new information becomes available in future periods, we may be required to revise our estimated useful lives. If the revised useful lives are shorter than originally estimated, our future amortization expense will increase.

In late 2024, we revised our commercial strategy for the IDgenetix test, reallocating resources to inside sales and non-personal promotions. In December 2024, we observed month-to-month decreases in IDgenetix test reports, which persisted through year-end. We continue to offer the IDgenetix test and monitor its performance; nevertheless, we anticipate that test report volumes and net revenues will decrease in 2025. Long-term projections about the performance of this test remain uncertain. We believe these factors indicated a need to revise the remaining useful life of our IDgenetix developed technology intangible asset. On December 1, 2024, we adjusted the estimated remaining useful life from approximately 12 years to 13 months, with the useful life now expected to end on December 31, 2025.

Goodwill

Our goodwill is not amortized but is tested for impairment annually and whenever events or changes in circumstances indicate that it may be impaired. We perform annual impairment reviews of our goodwill balance during the fourth quarter of each year, or more frequently if management believes indicators of impairment exist. We may perform a qualitative assessment to determine if it is necessary to perform a quantitative impairment test. If we determine that a quantitative impairment test is necessary, we apply the guidance in Accounting Standards Update (“ASU”) No. 2017-04, Intangibles—Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment, by comparing the fair value of the reporting unit to its carrying value, including the goodwill. If the carrying value exceeds the fair value, we recognize an impairment loss for the amount by which the carrying value exceeds fair value, up to the total amount of goodwill allocated to the reporting unit. We did not incur any goodwill impairment losses in any of the periods presented. We have concluded that our business is comprised of a single reporting unit. For our annual impairment test for the year ended December 31, 2024, we elected to bypass the qualitative assessment and proceeded directly to the quantitative assessment by comparing our reporting unit’s fair value to its

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carrying value. Factors that could result in an impairment of goodwill in the future include declines in the price of our common stock, increased competition, changes in macroeconomic developments and unfavorable government or regulatory developments.

We conducted annual impairment testing of goodwill in the fourth quarter which indicated that the fair value of our reporting unit exceeded its carrying value by 117% and therefore no impairment was indicated. To measure the fair value of our single reporting unit, we used a market approach whereby we calculated our total market capitalization on the impairment test date, based on the closing price of our common stock as reported on the Nasdaq Global Market, and applied a reasonable control premium. The control premium was based on an analysis of control premiums paid in recent acquisitions of companies in the same or similar industry as us.

Recent Accounting Pronouncements

In November 2023, the FASB issued ASU No. 2023-07, Segment Reporting (Topic 280)—Improvements to Reportable Segment Disclosures (“ASU 2023-07”), which require public companies disclose significant segment expenses and other segment items on an annual and interim basis and to provide in interim periods all disclosures about a reportable segment’s profit or loss and assets that are currently required annually. The guidance was effective for public entities for fiscal years beginning after December 15, 2023, and interim periods within fiscal years beginning after December 15, 2024. Early adoption was permitted. The guidance was applied retrospectively to all periods presented in the financial statements, unless it was impracticable. We have adopted the guidance under this ASU 2023-07 on a retrospective basis with an effective date January 1, 2022. Please refer to Note 17 - Segment and Related Information, to our Consolidated Financial Statements for details.

In December 2023, the FASB issued ASU No. 2023-09, Income Taxes (Topic 740)—Improvements to Income Tax Disclosures ("ASU 2023-09"), which is intended to enhance the transparency and decision usefulness of income tax disclosures. The amendments in ASU 2023-09 provide for enhanced income tax information primarily through changes to the rate reconciliation and income taxes paid information. ASU 2023-09 is effective for the Company prospectively to all annual periods beginning after December 15, 2024. Early adoption is permitted. We are currently evaluating the impact this update will have on the consolidated financial statements and disclosures.

In November 2024, the FASB issued ASU No. 2024-03, Income Statement—Reporting Comprehensive Income (Subtopic 220-40)—Expense Disaggregation Disclosures: Disaggregation of Income Statement Expenses (“ASU 2024-03”), which specifies additional disclosure requirements. The amendments in ASU 2024-03 require disclosure about the composition of certain income expense line items, such as purchases of inventory, employee compensation, and other expenses, as well as disclosure about selling expenses. The ASU is effective for fiscal years beginning after December 15, 2026, and interim periods beginning after December 15, 2027. Early adoption is permitted. We are currently evaluating the impact this update will have on the consolidated financial statements and disclosures.

We have evaluated all other recently issued, but not yet effective, accounting pronouncements and do not believe that these accounting pronouncements will have any material impact on our consolidated financial statements or disclosures upon adoption.

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

Interest Rate Risk

We are exposed to market risks in the ordinary course of our business. These risks primarily relate to interest rates fluctuations. We had cash and cash equivalents of $119.7 million as of December 31, 2024, which include bank deposits and money market funds. We had marketable investment securities of $173.4 million as of December 31, 2024, which are U.S. government securities and trading securities. Due to the nature of these instruments, we believe that we have no material exposure to interest rate risk.

As of December 31, 2024, we had a term debt of $10.0 million consisting of an outstanding term loan which bears interest at a floating rate that fluctuates with the WSJ Prime Rate, subject to an interest rate floor of 6.00%. During 2024, the U.S. Federal Reserve lowered interest rates on three separate occasions: by 50 basis points in September 2024, by 25 basis points in November 2024 and by 25 basis points in December 2024. The WSJ Prime Rate decreased by the same basis points for each respective adjustment thereafter.

A hypothetical 10% change in interest rates during any of the periods presented would not have a material impact on future interest income or expense, fair values of portfolio of investments, fair value of long-term debt and related cash flows.

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Inflation Risk

Our exposure to inflationary pressures is primarily in personnel and related costs. The extent of any future impacts from inflation on our business and our results of operations will be dependent upon how long the elevated inflation levels persist and if the rate of inflation were to further increase, neither of which we are able to predict. If elevated levels of inflation were to persist or if the rate of inflation were to accelerate, the purchasing power of our cash and cash equivalents may be eroded, our expenses could increase faster than anticipated and we may utilize our capital resources sooner than expected. Further, given the complexities of the reimbursement landscape in which we operate, our payors may be unwilling or unable to increase reimbursement rates to compensate for inflationary impacts.

Equity Price Risk

As of December 31, 2024, we had equity securities with a total fair value of $3.6 million. A hypothetical 10% decrease in the market price of our trading securities as of December 31, 2024 would decrease the fair value by approximately $0.4 million. These securities are subject to a wide variety and number of market-related risks that could substantially reduce or increase the fair value of our holdings.

Item 8. Financial Statements and Supplementary Data.

The financial statements and supplementary data required by this item are included after the Signature page of this Annual Report on Form 10-K beginning on page F-1.

Item 9. Changes in and Disagreements With Accountants on Accounting and Financial Disclosure.

None.

Item 9A. Controls and Procedures.

Evaluation of Disclosure Controls and Procedures

We maintain “disclosure controls and procedures,” as defined in Rules 13a-15(e) and 15d-15(e) under the Exchange Act, that are designed to ensure that information required to be disclosed in the reports that we file or submit under the Exchange Act is (1) recorded, processed, summarized and reported, within the time periods specified in the SEC’s rules and forms and (2) accumulated and communicated to our management, including our principal executive officer and principal financial officer, to allow timely decisions regarding required disclosure. Management recognizes that any controls and procedures, no matter how well designed and operated, can provide only reasonable assurance of achieving their objectives and management necessarily applies its judgment in evaluating the cost-benefit relationship of possible controls and procedures.

Our management, with the participation of our Chief Executive Officer and Chief Financial Officer, evaluated the effectiveness of our disclosure controls and procedures as of December 31, 2024. Based upon the evaluation, our Chief Executive Officer and Chief Financial Officer concluded that, as of December 31, 2024, our disclosure controls and procedures were effective at the reasonable assurance level.

Management’s Report on Internal Control over Financial Reporting

Our management is responsible for establishing and maintaining adequate internal control over financial reporting as such term as defined in Exchange Act Rule 13a-15(f). Internal control over financial reporting is a process designed under the supervision and with the participation of our management, including our principal executive officer and principal financial officer, to provide reasonable assurance regarding the reliability of financial reporting and the preparation of consolidated financial statements for external purposes in accordance with U.S. GAAP.

As of December 31, 2024, our management assessed the effectiveness of our internal control over financial reporting using the criteria set forth by the Committee of Sponsoring Organizations of the Treadway Commission in Internal Control-Integrated Framework (2013 Framework). Based on this assessment, our management concluded that, as of December 31, 2024, our internal control over financial reporting was effective based on those criteria.

Our independent registered public accounting firm, KPMG LLP, has audited the effectiveness of our internal control over financial reporting as of December 31, 2024, as stated in its attestation report contained in Item 15 of this Annual Report on Form 10-K.

Changes in Internal Control over Financial Reporting

There have been no changes in our internal control over financial reporting (as defined in Rules 13a-15(f) or 15d-15(f) of the Exchange Act) that occurred during the fourth quarter of 2024 that have materially affected, or are reasonably likely to materially affect, the Company’s internal control over financial reporting.

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Item 9B. Other Information.

Securities Trading Plans of Directors and Executive Officers

On November 11, 2024, Derek Maetzold, our Chief Executive Officer, adopted a Rule 10b5-1 trading arrangement providing for the sale from time to time of an aggregate of up to 301,404 shares of our common stock, less the number of shares withheld to cover tax withholding obligations in connection with the vesting and settlement of outstanding RSUs and PSUs, and less any shares that are sold under his previous arrangement. The trading arrangement is intended to satisfy the affirmative defense in Rule 10b5-1(c). The duration of the trading arrangement will be from February 24, 2025 through August 13, 2025.

On November 18, 2024, Frank Stokes, our Chief Financial Officer, adopted a Rule 10b5-1 trading arrangement providing for the sale from time to time of up to 100% of the shares of our common stock issued upon the settlement of 14,617 outstanding RSUs, less the number of shares withheld to cover tax withholding obligations in connection with the vesting and settlement of such RSUs. The trading arrangement is intended to satisfy the affirmative defense in Rule 10b5-1(c). The duration of the trading arrangement will be from February 18, 2025 through December 31, 2026 or earlier if all transactions under the trading arrangement are completed.

No other officers or directors, as defined in Rule 16a-1(f), adopted and/or terminated a Rule 10b5-1 trading arrangement or a non-Rule 10b5-1 trading arrangement, as defined in Regulation S-K Item 408, during the last fiscal quarter.

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

Not applicable.

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PART III

Certain information required by Part III is omitted from this Annual Report on Form 10-K since we intend to file our definitive proxy statement for our 2025 Annual Meeting of Stockholders (the “Proxy Statement”) pursuant to Regulation 14A of the Exchange Act, not later than 120 days after the end of the fiscal year covered by this Annual Report on Form 10-K, and certain information to be included in the Proxy Statement is incorporated herein by reference.

Item 10. Directors, Executive Officers and Corporate Governance.

The information required by this item is to be included in the Proxy Statement as follows:

•The information relating to our executive officers is to be included in the section entitled “Executive Officers,”

•The information relating to our directors and nominees for director is to be included in the section entitled “Proposal 1: Election of Directors,”

•The information relating to our audit committee and audit committee financial expert is to be included in the section entitled “Information Regarding the Board of Directors and Corporate Governance,” and

•If required, the information regarding delinquent reports under Section 16(a) of the Exchange Act is to be included in the section entitled “Delinquent Section 16(a) Reports.”

Such information is to be included in the Proxy Statement and is incorporated herein by reference.

The information required by Item 408(b) of Regulation S-K will be set forth in the section captioned “Insider Trading Arrangements and Policies” in our Proxy Statement and is incorporated herein by reference.

We have adopted a written Code of Business Conduct and Ethics (“Ethics Code”) that applies to all officers, directors and employees, including our principal executive officer, principal financial officer, principal accounting officer or controller, or persons performing similar functions. The Ethics Code is available on our website at www.CastleBiosciences.com. If we ever were to amend or waive any provision that applies to our principal executive officer, principal financial officer, principal accounting officer or any person performing similar functions, we intend to satisfy our disclosure obligations, if any, with respect to any such waiver or amendment by posting such information on our website, rather than by filing a Current Report on Form 8-K.

Item 11. Executive Compensation.

The information required by this item is to be included in the Proxy Statement under the section entitled “Executive Compensation” and is incorporated herein by reference, provided that the information required by Item 402(x) of Regulation S-K shall be set forth in the section headed “Policies and practices related to the grant of certain equity awards close in time to the release of material nonpublic information” in the Proxy Statement and is incorporated herein by reference.

Item 12. Security Ownership of Certain Beneficial Owners and Management and Related Stockholder Matters.

The information required by this item with respect to equity compensation plans is to be included in the Proxy Statement under the section entitled “Equity Compensation Plan Information” and the information required by this item with respect to security ownership of certain beneficial owners and management is to be included in the Proxy Statement under the section entitled “Security Ownership of Certain Beneficial Owners and Management” and in each case is incorporated herein by reference.

Item 13. Certain Relationships and Related Transactions, and Director Independence.

The information required by this item is to be included in the Proxy Statement under the section entitled “Transactions with Related Persons and Indemnifications—Related Person Transactions Policy and Procedures” and is incorporated herein by reference.

Item 14. Principal Accountant Fees and Services.

Our independent registered public accounting firm is KPMG LLP, Houston, TX, PCAOB ID: 185.

The information required by this item is to be included in the Proxy Statement under the section entitled “Proposal 2: Ratification of Selection of Independent Registered Public Accounting Firm” and is incorporated herein by reference.

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PART IV

Item 15. Exhibit and Financial Statement Schedules.

(a)(1) Financial Statements.

The consolidated financial statements and supplementary data required by this item are included after the Signature page of this Annual Report on Form 10-K beginning on page F-1.

(a)(2) Financial Statement Schedules.

All schedules have been omitted because they are not required or because the required information is given in the Consolidated Financial Statements or Notes thereto.

(a)(3) Exhibits.

The exhibits listed in the Exhibit Index below are filed or incorporated by reference as part of this Annual Report on Form 10-K.

Exhibit Index

Exhibit Number Description of document

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Exhibit Number Description of document

99

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Exhibit Number Description of document

100

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Exhibit Number Description of document

19.1* Insider Trading Policy

21.1* Subsidiaries of the Registrant.

23.1* Consent of KPMG LLP, Independent Registered Public Accounting Firm.

101.SCH* Inline XBRL Taxonomy Extension Schema.

101.CAL* Inline XBRL Taxonomy Extension Calculation Linkbase.

101.DEF* Inline XBRL Taxonomy Extension Definition Linkbase.

101.LAB* Inline XBRL Taxonomy Extension Label Linkbase.

101.PRE* Inline XBRL Taxonomy Extension Presentation Linkbase.

_____________________________________

* Filed herewith

** Furnished herewith.

+ Indicates management contract or compensatory plan.

# Pursuant to Item 601(b)(10) of Regulation S-K, certain portions of this exhibit have been omitted (indicated by “[***]”) because the Company has determined that the information is not material and is the type that the Company treats as private or confidential.

† Certain schedules or exhibits have been omitted pursuant to Item 601(a)(5) of Regulation S-K. A copy of any omitted schedule or exhibit will be furnished to the SEC upon request; provided, however, that we may request confidential treatment pursuant to Rule 24b-2 of the Exchange Act for any schedule or exhibit so furnished.

^ Pursuant to Item 601(b)(2) of Regulation S-K, certain portions of this exhibit have been omitted (indicated by “[***]”) because the Company has determined that the information is not material and is the type that the Company treats as private or confidential.

Item 16. Form 10-K Summary.

None.

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SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

CASTLE BIOSCIENCES, INC.

Date: February 27, 2025 By: /s/ Derek J. Maetzold

Pursuant to the requirements of the Securities Exchange Act of 1934, this report has been signed below by the following persons on behalf of the Registrant and in the capacity and on the dates indicated.

SIGNATURE TITLE DATE

(Derek J. Maetzold) (Principal Executive Officer)

/s/ Frank Stokes Chief Financial Officer February 27, 2025

(Frank Stokes) (Principal Financial and Accounting Officer)

/s/ Daniel M. Bradbury Chairperson of the Board of Directors February 27, 2025

(Daniel M. Bradbury)

/s/ Kimberlee S. Caple Member of the Board of Directors February 27, 2025

(Kimberlee S. Caple)

/s/ G. Bradley Cole Member of the Board of Directors February 27, 2025

(G. Bradley Cole)

/s/ Rodney Cotton Member of the Board of Directors February 27, 2025

(Rodney Cotton)

/s/ Ellen Goldberg Member of the Board of Directors February 27, 2025

(Ellen Goldberg)

/s/ Miles D. Harrison Member of the Board of Directors February 27, 2025

(Miles D. Harrison)

/s/ Tiffany P. Olson Member of the Board of Directors February 27, 2025

(Tiffany P. Olson)

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INDEX TO CONSOLIDATED FINANCIAL STATEMENTS

Report of Independent Registered Public Accounting Firm F-2

Consolidated Balance Sheets as of December 31, 2024 and 2023 F-4

Notes to the Consolidated Financial Statements F-10

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Report of Independent Registered Public Accounting Firm

To the Stockholders and Board of Directors

Castle Biosciences, Inc.:

Opinions on the Consolidated Financial Statements and Internal Control Over Financial Reporting

We have audited the accompanying consolidated balance sheets of Castle Biosciences, Inc. and subsidiaries (the Company) as of December 31, 2024 and 2023, the related consolidated statements of operations, comprehensive income (loss), stockholders’ equity, and cash flows for each of the years in the three-year period ended December 31, 2024, and the related notes (collectively, the consolidated financial statements). We also have audited the Company’s internal control over financial reporting as of December 31, 2024, based on criteria established in Internal Control – Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission.

In our opinion, the consolidated financial statements referred to above present fairly, in all material respects, the financial position of the Company as of December 31, 2024 and 2023, and the results of its operations and its cash flows for each of the years in the three-year period ended December 31, 2024, in conformity with U.S. generally accepted accounting principles. Also in our opinion, the Company maintained, in all material respects, effective internal control over financial reporting as of December 31, 2024 based on criteria established in Internal Control – Integrated Framework (2013) issued by the Committee of Sponsoring Organizations of the Treadway Commission.

Basis for Opinions

The Company’s management is responsible for these consolidated financial statements, for maintaining effective internal control over financial reporting, and for its assessment of the effectiveness of internal control over financial reporting, included in the accompanying Management's Report on Internal Control over Financial Reporting. Our responsibility is to express an opinion on the Company’s consolidated financial statements and an opinion on the Company’s internal control over financial reporting based on our audits. We are a public accounting firm registered with the Public Company Accounting Oversight Board (United States) (PCAOB) and are required to be independent with respect to the Company in accordance with the U.S. federal securities laws and the applicable rules and regulations of the Securities and Exchange Commission and the PCAOB.

We conducted our audits in accordance with the standards of the PCAOB. Those standards require that we plan and perform the audits to obtain reasonable assurance about whether the consolidated financial statements are free of material misstatement, whether due to error or fraud, and whether effective internal control over financial reporting was maintained in all material respects.

Our audits of the consolidated financial statements included performing procedures to assess the risks of material misstatement of the consolidated financial statements, whether due to error or fraud, and performing procedures that respond to those risks. Such procedures included examining, on a test basis, evidence regarding the amounts and disclosures in the consolidated financial statements. Our audits also included evaluating the accounting principles used and significant estimates made by management, as well as evaluating the overall presentation of the consolidated financial statements. Our audit of internal control over financial reporting included obtaining an understanding of internal control over financial reporting, assessing the risk that a material weakness exists, and testing and evaluating the design and operating effectiveness of internal control based on the assessed risk. Our audits also included performing such other procedures as we considered necessary in the circumstances. We believe that our audits provide a reasonable basis for our opinions.

Definition and Limitations of Internal Control Over Financial Reporting

A company’s internal control over financial reporting is a process designed to provide reasonable assurance regarding the reliability of financial reporting and the preparation of financial statements for external purposes in accordance with generally accepted accounting principles. A company’s internal control over financial reporting includes those policies and procedures that (1) pertain to the maintenance of records that, in reasonable detail, accurately and fairly reflect the transactions and dispositions of the assets of the company; (2) provide reasonable assurance that transactions are recorded as necessary to permit preparation of financial statements in accordance with generally accepted accounting principles, and that receipts and expenditures of the company are being made only in accordance with authorizations of management and directors of the company; and (3) provide reasonable assurance regarding prevention or timely detection of unauthorized acquisition, use, or disposition of the company’s assets that could have a material effect on the financial statements.

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Because of its inherent limitations, internal control over financial reporting may not prevent or detect misstatements. Also, projections of any evaluation of effectiveness to future periods are subject to the risk that controls may become inadequate because of changes in conditions, or that the degree of compliance with the policies or procedures may deteriorate.

Critical Audit Matter

The critical audit matter communicated below is a matter arising from the current period audit of the consolidated financial statements that was communicated or required to be communicated to the audit committee and that: (1) relates to accounts or disclosures that are material to the consolidated financial statements and (2) involved our especially challenging, subjective, or complex judgments. The communication of a critical audit matter does not alter in any way our opinion on the consolidated financial statements, taken as a whole, and we are not, by communicating the critical audit matter below, providing a separate opinion on the critical audit matter or on the accounts or disclosures to which it relates.

Measurement of test revenue

As discussed in Notes 2 and 3 of the consolidated financial statements, test revenue is recognized when the performance obligation is satisfied, upon delivery of the test report. The amount of revenue recognized reflects the amount of consideration to which the Company expects to be entitled and considers the effects of variable consideration. The measurement of test revenue is determined by contractually established rates as well as historical average collection rates by test type and payor category taking into consideration the range of possible outcomes, the predictive value of the Company’s past experiences, the time period of when uncertainties expect to be resolved and the amount of consideration that is susceptible to factors outside of the Company’s influence, such as the judgment and actions of third parties. The Company reported net revenues of $332.1 million for the year ended December 31, 2024, a portion of which related to test revenue.

We identified the evaluation of the measurement of test revenue as a critical audit matter. Evaluating the measurement of test revenue, specifically the estimation of the amount of test revenue expected to be collectible related to commercial payors and certain others, required especially complex and subjective auditor judgment.

The following are the primary procedures we performed to address this critical audit matter. We evaluated the design and tested the operating effectiveness of certain internal controls related to the estimation of the expected collectible test revenue related to commercial payors and certain others. This included controls related to management’s review of the assumptions and inputs used in the determination of test revenue expected to be collectible from commercial payors and certain others. For a selection of tests, we evaluated certain historical data inputs that are used in management’s model to estimate test revenue expected to be collectible by comparing the data from the model to physician test requisition forms, proof of delivery, and cash collection activity. These data inputs included collection activity, amounts of historical claims, insurance payor categories, test dates, test types, claim aging categories, and revenue recognition dates. In addition, we inquired of the individuals who are responsible for monitoring and tracking the status of anticipated collections to understand the progress of these activities and any impact to management’s estimates.

/s/ KPMG LLP

We have served as the Company’s auditor since 2018.

Houston, Texas

February 27, 2025

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CASTLE BIOSCIENCES, INC.

CONSOLIDATED BALANCE SHEETS

(in thousands, except share and per share data)

December 31,

ASSETS

Current Assets

Prepaid expenses and other current assets 7,671 6,292

Long-term accounts receivable, net 918 1,191

LIABILITIES AND STOCKHOLDERS’ EQUITY

Current Liabilities

Current portion of long-term debt 278 —

Other accrued and current liabilities 7,993 7,317

Long-term debt 9,745 —

Noncurrent operating lease liabilities 14,345 14,173

Noncurrent finance lease liabilities 311 25

Commitments and Contingencies (Note 13)

Stockholders’ Equity

Accumulated other comprehensive income 230 136

Total liabilities and stockholders’ equity $ 531,235 $ 453,340

The accompanying notes are an integral part of these consolidated financial statements.

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CASTLE BIOSCIENCES, INC.

CONSOLIDATED STATEMENTS OF OPERATIONS

(in thousands, except per share data)

Years Ended December 31,

OPERATING EXPENSES AND OTHER OPERATING INCOME

Change in fair value of contingent consideration — — (18,287)

Changes in fair value of trading securities 555 — —

Earnings (loss) per share:

Weighted-average shares outstanding:

The accompanying notes are an integral part of these consolidated financial statements.

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CASTLE BIOSCIENCES, INC.

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS)

(in thousands)

Years Ended December 31,

Other comprehensive income (loss):

The accompanying notes are an integral part of these consolidated financial statements.

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CASTLE BIOSCIENCES, INC.

CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY

(in thousands, except share data)

Shares Amount

Stock-based compensation expense — — 36,321 — — 36,321

Net unrealized loss on marketable investment securities — — — — (381) (381)

Stock-based compensation expense — — 51,219 — — 51,219

Net unrealized gain on marketable investment securities — — — — 517 517

Stock-based compensation expense — — 50,320 — — 50,320

Net unrealized gain on marketable investment securities — — — — 94 94

The accompanying notes are an integral part of these consolidated financial statements.

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CASTLE BIOSCIENCES, INC.

CONSOLIDATED STATEMENTS OF CASH FLOWS

(in thousands)

Years Ended December 31,

OPERATING ACTIVITIES

Change in fair value of contingent consideration — — (18,287)

Change in fair value of trading securities (555) — —

Change in operating assets and liabilities:

Prepaid expenses and other current assets (1,142) (435) (1,224)

Other accrued and current liabilities 320 2,139 (963)

Net cash provided by (used in) operating activities 64,866 (5,626) (41,655)

INVESTING ACTIVITIES

Proceeds from maturities of marketable investment securities 183,900 186,500 —

Proceeds from sale of property and equipment 18 13 195

Acquisition of business, net of cash and cash equivalents acquired — — (26,966)

Asset acquisitions, net of cash and cash equivalents acquired — — 547

FINANCING ACTIVITIES

Proceeds from exercise of common stock options 2,017 269 833

Repayment of principal portion of finance lease liabilities (97) (142) (122)

Proceeds from issuance of term debt 10,000 — —

Net cash provided by (used in) financing activities 6,139 (2,298) 1,515

The accompanying notes are an integral part of these consolidated financial statements.

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CASTLE BIOSCIENCES, INC.

CONSOLIDATED STATEMENTS OF CASH FLOWS (Continued)

(in thousands)

Years Ended December 31,

SUPPLEMENTAL DISCLOSURE OF CASH PAID FOR:

DISCLOSURE OF NON-CASH INVESTING AND FINANCING ACTIVITIES:

Accrued purchases of property and equipment $ 2,231 $ 1,226 $ 1,396

Finance lease assets obtained in exchange for lease obligations $ 218 $ — $ —

Common stock issued in acquisition of business $ — $ — $ 17,111

The accompanying notes are an integral part of these consolidated financial statements.

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CASTLE BIOSCIENCES, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS

1. Organization and Description of Business

Castle Biosciences, Inc. (the ‘‘Company,” “we,” “us” or “our”) was incorporated in the state of Delaware on September 12, 2007. We are a commercial-stage diagnostics company focused on providing clinicians and their patients with personalized, clinically actionable information to inform treatment decisions and improve health outcomes. We are based in Friendswood, Texas (a suburb of Houston, Texas) and our laboratory operations are conducted at our facilities located in Phoenix, Arizona and Pittsburgh, Pennsylvania.

2. Summary of Significant Accounting Policies

Basis of Presentation

The consolidated financial statements include the accounts of Castle Biosciences, Inc. and our wholly owned subsidiaries and have been prepared in conformity with accounting principles generally accepted in the United States of America (‘‘U.S. GAAP’’).All intercompany accounts and transactions have been eliminated in consolidation.

In connection with preparing consolidated financial statements for each annual and interim reporting period, the Company is required to evaluate whether there are conditions or events, considered in aggregate, that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the financial statements are issued. Substantial doubt exists when conditions and events, considered in aggregate, indicate that it is probable that a company will be unable to meet its obligations as they become due within one year after the date that the consolidated financial statements are issued. This evaluation initially does not take into consideration the potential mitigating effect of management’s plans and actions that have not been fully implemented as of the date that the financial statements are issued. When substantial doubt exists, management evaluates whether the mitigating effect of its plans sufficiently alleviates substantial doubt about the Company’s ability to continue as a going concern. The mitigating effect of management’s plans, however, is only considered if both: (1) it is probable that the plans will be effectively implemented within one year after the date that the financial statements are issued; and (2) it is probable that the plans, when implemented, will mitigate the relevant conditions or events that raise substantial doubt about the Company’s ability to continue as a going concern within one year after the date that the financial statements are issued. Generally, to be considered probable of being effectively implemented, the plans must have been approved before the date that the financial statements are issued.

We have a history of recurring net losses and negative cash flows and as of December 31, 2024, we had an accumulated deficit of $200.1 million. We believe our $119.7 million of cash and cash equivalents, and $173.4 million of marketable investment securities as of December 31, 2024, and anticipated revenue from our test reports will be sufficient to meet our cash requirements through at least the 12-month period following the date that these consolidated financial statements were issued.

Use of Estimates

The preparation of consolidated financial statements in conformity with U.S. GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the consolidated financial statements and the reported amounts of revenues and expenses during the reporting period. Significant items subject to such estimates include revenue recognition, the valuation of stock-based compensation, assessing future tax exposure and the realizability of deferred tax assets, the useful lives and recoverability of long-lived assets, the goodwill impairment test, the valuation of acquired intangible assets and the valuation of contingent consideration and other contingent liabilities. We base these estimates on historical and anticipated results, trends, and various other assumptions that we believe are reasonable under the circumstances, including assumptions as to future events. These estimates form the basis for making judgments about the carrying values of assets and liabilities and recorded revenues and expenses that are not readily apparent from other sources. Actual results could differ from those estimates and assumptions.

Segment Reporting

Operating segments are components of an enterprise engaging in business activities from which it may recognize revenues and incur expenses, where discrete financial information is available, and where its operating results are regularly reviewed by the public entity's chief operating decision maker (“CODM”) to make decisions about resources to be allocated to the segment and to assess its performance. A CODM may be an individual or a

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CASTLE BIOSCIENCES, INC.

NOTES TO CONSOLIDATED FINANCIAL STATEMENTS (Continued)

decision-making group. A reportable segment consists of one or more operating segments. For additional information on our segment reporting, see Note 17.

Cash and Cash Equivalents including Concentrations of Credit Risk

Cash equivalents consist of short-term, highly liquid investments with original maturities of three months or less. Our cash equivalents consist of money market funds, which are not insured by the Federal Deposit Insurance Corporation (“FDIC”), that are primarily invested in short-term U.S. government obligations.Cash deposits at financial institutions may exceed the amount of insurance provided by the FDIC. Management believes that we are not exposed to significant credit risk on our cash deposits due to the financial position of the financial institutions in which deposits are held.

Marketable Investment Securities

Our marketable investment securities are comprised of debt and equity securities. All debt securities are recognized in accordance with Financial Accounting Standards Board (“FASB”) Accounting Standards Codification (“ASC”) Topic 320, Investments-Debt Securities (“ASC 320”). Management determines the appropriate classification of debt securities at the time of purchase and re-evaluates such determination at each balance sheet date. All debt securities are classified as available-for-sale (“AFS”) and are recorded at fair value in accordance with ASC 320. We recognize the unrealized gains and losses related to changes in fair value as a separate component of accumulated other comprehensive income (loss) within total stockholders’ equity, net of any related deferred income tax effects, on the consolidated balance sheets. Premiums or discounts from par value are amortized over the life of the underlying investment and are included in interest income in the consolidated statements of operations. Realized gains and losses on available-for-sale securities, if any, are calculated at the individual security level and are included in interest income in the consolidated statements of operations. Impairments of available-for-sale debt securities, if any, are recorded in the consolidated statements of operations.

Our equity securities consist of investments in shares of common stock which are listed and traded on the Nasdaq Global Market. All trading securities are recognized in accordance with ASC Topic 321, Investments-Equity Securities and reported at their readily determinable fair values as quoted by market exchanges where changes in fair value are included in changes in fair value of trading securities in the consolidated statements of operations. All changes in a marketable security’s fair value are reported in earnings as they occur, as such, the sale of our trading securities does not necessarily give rise to a significant gain or loss. Investments in equity securities are classified as either current or long-term depending upon management’s intentions. See Notes 5 and 12 for further details.

Revenue Recognition

In accordance with ASC Topic 606, Revenue from Contracts with Customers (“ASC 606”),we follow a five-step process to recognize revenues: (1) identify the contract with the customer, (2) identify the performance obligations, (3) determine the transaction price, (4) allocate the transaction price to the performance obligations and (5) recognize revenues when the performance obligations are satisfied. We have determined that we have a contract with the patient when the treating clinician orders the test. Our contracts generally contain a single performance obligation, which is the delivery of the test report, and we satisfy our performance obligation at a point in time upon the delivery of the test report to the treating clinician, at which point we can bill for the report. The amount of revenue recognized reflects the amount of consideration to which we expect to be entitled, or the transaction price, and considers the effects of variable consideration. See Note 3 for further details.

Accounts Receivable and Allowance for Credit Losses

We classify accounts receivable balances that are expected to be paid more than one year from the consolidated balance sheet date as noncurrent assets. The estimated timing of payment utilized as a basis for classification as noncurrent is determined by analyses of historical payor-specific payment experience, adjusted for known factors that are expected to change the timing of future payments.

We accrue an allowance for credit losses against our accounts receivable based on management’s current estimate of amounts that will not be collected. Management’s estimates are typically based on historical loss information adjusted for current conditions. We generally do not perform evaluations of customers’ financial condition and generally do not require collateral. Historically, our credit losses have not been significant. The allowance for credit losses was zero as of December 31, 2024 and 2023. Adjustments for implicit price concessions attributable to variable consideration, as discussed below, are incorporated into the measurement of the accounts receivable balances and are not part of the allowance for credit losses.

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Inventory

We carry inventories of test supplies in our laboratory facilities. The inventories are carried at the lower of weighted average cost and net realizable value and expensed through cost of sales as the supplies are used.

Property and Equipment

Property and equipment are stated at cost less accumulated depreciation and amortization. Depreciation is computed using the straight-line method over the estimated useful lives of the assets, generally between five and ten years. Leasehold improvements are amortized using the straight-line method over the shorter of the estimated useful life of the asset or the term of the lease. Our leasehold improvements primarily relate to our office and laboratory facilities in Friendswood, Texas, Phoenix, Arizona and Pittsburgh, Pennsylvania, and are generally being depreciated through the end of the lease terms in 2025 and 2033, respectively. Maintenance and repairs are charged to expense as incurred, and material improvements are capitalized. Interest costs incurred during the construction of major capital projects are capitalized until the underlying asset is ready for its intended use, at which point the capitalized interest costs are amortized using the straight-line method over the estimated useful life of the underlying asset. When assets are retired or otherwise disposed of, the cost and accumulated depreciation are removed from the consolidated balance sheet and any resulting gain or loss is reflected in the consolidated statements of operations in the period realized.

Intangible Assets

Our intangible assets, which are comprised primarily of acquired developed technology, are considered to be finite-lived and are amortized on a straight-line basis over their estimated useful lives.

Goodwill

Goodwill represents the excess of the purchase price over the fair value of the net tangible and intangible assets acquired in a business combination. Goodwill is not amortized, but is tested for impairment. We test goodwill for impairment in the fourth quarter of each fiscal year and when events, or changes in circumstances, indicate that it may be impaired. Events and changes in circumstances indicating that goodwill may be impaired include sustained declines in the price of our common stock, increased competition, changes in macroeconomic developments, unfavorable government or regulatory developments and changes in coverage or reimbursement conditions.

Goodwill is tested for impairment at the reporting until level where goodwill is held. Testing begins with completion of an optional qualitative assessment. If the qualitative assessment suggests that impairment is more likely than not, quantitative testing is conducted. If the qualitative assessment is bypassed, we proceed directly to quantitative testing. Quantitative testing consists of comparing the carrying value of goodwill to its estimated fair value. Impairment of goodwill is the condition that exists when the carrying value exceeds its fair value. Amounts by which carrying value exceed fair value, up to the total amount of goodwill allocated to the reporting unit, are recognized as an impairment loss in the consolidated statements of operations.

Long-Lived Assets

We review long-lived assets for impairment whenever events or changes in circumstances indicate that the carrying amount of the assets may not be recoverable. An impairment loss is recognized when the total of estimated future undiscounted cash flows, expected to result from the use of the asset and its eventual disposition, are less than the carrying amount. Impairment, if any, would be calculated based on the excess of the carrying amount of the long-lived asset over the long-lived asset’s fair value. There were no impairment charges recognized during the years ended December 31, 2024, 2023 and 2022.

Acquisitions

We assess acquisitions under ASC Topic 805, Business Combinations (“ASC 805”), to determine whether a transaction represents the acquisition of assets or a business combination. Under this guidance, we apply a two-step model. The first step involves a screening test where we evaluate whether substantially all of the fair value of the gross assets acquired is concentrated in a single asset or a group of similar assets. If the screening test is met, we account for the set as an asset acquisition. If the screening test is not met, we apply the second step of the model to determine if the set meets the definition of a business based on the guidance in ASC 805. If so, the transaction is treated as a business combination. Otherwise, it is treated as an asset acquisition. Asset acquisitions are accounted for by allocating the cost of the acquisition, including transaction costs, to the individual assets acquired and liabilities assumed on a relative fair value basis without recognition of goodwill. Business combinations

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are accounted for using the acquisition method. Under the acquisition method, goodwill is measured as a residual amount equal to the fair value of the consideration transferred less the net recognized fair value of the identifiable assets acquired and the liabilities assumed, as of the acquisition date, and transaction costs are expensed as incurred.

Contingent Consideration

Under the terms of business combinations or asset acquisitions, we may be required to pay additional contingent consideration if specified future events occur or if certain conditions are met.

In a business combination, in accordance with ASC 805, contingent consideration is recorded at fair value as of the acquisition date and classified as liabilities or equity based on applicable U.S. GAAP. For contingent consideration classified as liabilities, we remeasure the contingent consideration at fair value each period with changes in fair value recorded in the statements of operations each period.

For contingent consideration in transactions that are not business combinations, we apply U.S. GAAP. With respect to additional contingent consideration that must or may be settled by issuance of a variable number of shares, we account for the contingent consideration as a liability in accordance with ASC Topic 480, Distinguishing Liabilities from Equity (“ASC 480”). In accordance with ASC 480, we record the contingent consideration initially and subsequently at fair value with changes in fair value recorded in the statements of operations each period.

Contingent consideration is classified as current or noncurrent in the consolidated balance sheets based on the contractual timing of future settlement. For additional information on the contingent consideration, see Notes 6 and 12.

Leases

We account for leases in accordance with ASC Topic 842, Leases (“ASC 842”). We categorize leases at their commencement as either operating or finance leases based on the criteria in ASC 842. Under ASC 842, we record right-of-use (“ROU”) assets and lease liabilities for each lease arrangement identified, except that we have elected the short-term lease exemption for all leases with a term of 12 months or less. Lease liabilities are recorded at the present value of future lease payments discounted using our incremental borrowing rate for the lease established at the commencement date and ROU assets are measured at the amount of the lease liability plus any initial direct costs, less any lease incentives received before commencement. For our operating leases, we recognize a single lease cost over the lease term on a straight-line basis. We have elected the practical expedient of not separating nonlease components from lease components in all leases. See Note 11 for details on our leases.

Cost of Sales (exclusive of amortization of acquired intangible assets)