XFOR US Equity

X4 Pharmaceuticals, Inc

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Health Care · Biological Products, (No Diagnostic Substances) · CIK 1501697 · FYE 1231

$3.93

-0.01 (-0.25%)

USD · as of 2026-07-28 · marketstack

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Institutional ownership· 13F filers holding XFOR · 2026-Q1 methodology → sources →

84 holders

% of shares outstanding held

104.4%

Shares held (13F)

98,479,119

Reporting holders

Institutional 13F holdings sum to 104.4% of shares outstanding. Readings above 100% reflect securities-lending double counting: shares on loan to short sellers are reported long by both the lending institution and the one that bought them. FINRA short interest of 3,117,372 shares (settlement 2026-04-30) accounts for the excess.

Top holders

largest 84 of 84 · Δ vs 2025-Q4

#	Holder	Shares	Value	% of shares out	Δ QoQ
1	MORGAN STANLEY	9,466,9929.5M	$39M	10.04%	ADD 15%
2	Empery Asset Management, LP	8,944,1188.9M	$37M	9.48%	—
3	FMR LLC	8,103,4008.1M	$33M	8.59%	TRIM -5%
4	Bain Capital Life Sciences Investors, LLC	7,967,4548.0M	$33M	8.45%	—
5	Kalehua Capital Management LLC	7,445,6807.4M	$31M	7.89%	ADD 100%
6	PERCEPTIVE ADVISORS LLC	6,737,6486.7M	$28M	7.14%	ADD 7%
7	Saturn V Capital Management LP	6,456,6466.5M	$27M	6.85%	ADD 11%
8	Deep Track Capital, LP	6,339,5356.3M	$26M	6.72%	ADD 26%
9	VANGUARD CAPITAL MANAGEMENT LLC	3,497,6123.5M	$14M	3.71%	NEW†
10	BRAIDWELL LP	3,272,9543.3M	$14M	3.47%	TRIM -3%
11	NEA Management Company, LLC	3,233,7433.2M	$13M	3.43%	—
12	Rosalind Advisors, Inc.	3,214,7663.2M	$13M	3.41%	ADD 23%
13	Blackstone Inc.	2,681,9222.7M	$11M	2.84%	—
14	Trails Edge Capital Partners, LP	2,571,4782.6M	$11M	2.73%	—
15	Nantahala Capital Management, LLC	2,449,4682.4M	$10M	2.60%	—
16	BVF INC/IL	2,233,7422.2M	$9M	2.37%	—
17	SAMSARA BIOCAPITAL, LLC	1,832,5661.8M	$8M	1.94%	TRIM -7%
18	STEMPOINT CAPITAL LP	1,701,4841.7M	$7M	1.80%	ADD 89%
19	BlackRock, Inc.	1,211,7941.2M	$5M	1.28%	—
20	MILLENNIUM MANAGEMENT LLC	1,210,5141.2M	$5M	1.28%	ADD 2062%
21	Woodline Partners LP	1,001,0951.0M	$4M	1.06%	—
22	GEODE CAPITAL MANAGEMENT, LLC	939,726939,726	$4M	1.00%	—
23	GOLDMAN SACHS GROUP INC	882,134882,134	$4M	0.94%	ADD 6%
24	SUSQUEHANNA INTERNATIONAL GROUP, LLP	856,222856,222	$4M	0.91%	ADD 3768%
25	VANGUARD FIDUCIARY TRUST CO	480,733480,733	$2M	0.51%	NEW
26	STATE STREET CORP	403,534403,534	$2M	0.43%	ADD 104%
27	MARSHALL WACE, LLP	336,834336,834	$1M	0.36%	ADD 319%
28	Stonepine Capital Management, LLC	335,309335,309	$1M	0.36%	TRIM -44%
29	Venrock Adviser, LLC	330,525330,525	$1M	0.35%	NEW
30	UBS Group AG	267,340267,340	$1M	0.28%	ADD 6375%
31	ACORN CAPITAL ADVISORS, LLC	234,039234,039	$966,583	0.25%	TRIM -14%
32	Qube Research & Technologies Ltd	218,954218,954	$904,280	0.23%	ADD 223%
33	NORTHERN TRUST CORP	178,235178,235	$736,111	0.19%	—
34	Pale Fire Capital SE	167,590167,590	$692,147	0.18%	—
35	BANK OF AMERICA CORP /DE/	150,676150,676	$622,292	0.16%	ADD 321%
36	Affinity Asset Advisors, LLC	145,000145,000	$598,850	0.15%	—
37	Palumbo Wealth Management LLC	131,014131,014	$541,088	0.14%	ADD 16%
38	Brevan Howard Capital Management LP	127,321127,321	$525,836	0.13%	NEW
39	Susquehanna Portfolio Strategies, LLC	102,599102,599	$423,734	0.11%	ADD 137%
40	Dynamic Technology Lab Private Ltd	36,22136,221	$384,667	0.04%	NEW
41	CHARLES SCHWAB INVESTMENT MANAGEMENT INC	66,74966,749	$275,673	0.07%	—
42	OMERS ADMINISTRATION Corp	57,30057,300	$236,649	0.06%	TRIM -48%
43	Hudson Bay Capital Management LP	50,28750,287	$207,685	0.05%	ADD 56%
44	Catalyst Funds Management Pty Ltd	47,38347,383	$195,692	0.05%	NEW
45	JANE STREET GROUP, LLC	37,14337,143	$153,401	0.04%	TRIM -59%
46	CITIGROUP INC	35,76535,765	$147,709	0.04%	ADD 11%
47	Vanguard Global Advisers, LLC	32,97732,977	$136,195	0.03%	NEW
48	Diametric Capital, LP	28,97328,973	$119,658	0.03%	NEW
49	STIFEL FINANCIAL CORP	21,78921,789	$89,989	0.02%	ADD 6%
50	Invesco Ltd.	19,96819,968	$82,468	0.02%	NEW
51	Schonfeld Strategic Advisors LLC	19,51419,514	$80,592	0.02%	NEW
52	Jefferies Financial Group Inc.	19,47419,474	$80,428	0.02%	TRIM -25%
53	CAXTON CORP	15,55715,557	$64,249	0.02%	—
54	ExodusPoint Capital Management, LP	14,70314,703	$60,723	0.02%	TRIM -81%
55	TWO SIGMA INVESTMENTS, LP	13,86813,868	$57,275	0.01%	TRIM -20%
56	Creative Planning	13,81913,819	$57,072	0.01%	TRIM -16%
57	Virtu Financial LLC	12,73012,730	$53,000	0.01%	TRIM -43%
58	Jump Financial, LLC	12,31712,317	$50,869	0.01%	NEW
59	Vanguard Personalized Indexing Management, LLC	11,52511,525	$47,598	0.01%	NEW
60	SummitTX Capital, L.P.	11,20011,200	$46,256	0.01%	NEW
61	WINTON GROUP Ltd	10,60010,600	$43,778	0.01%	NEW
62	Indivisible Partners	10,00010,000	$37,000	0.01%	—
63	BNP PARIBAS FINANCIAL MARKETS	4,7564,756	$19,642	0.01%	ADD 831%
64	BARCLAYS PLC	2,8142,814	$11,622	0.00%	TRIM -95%
65	SIGNATUREFD, LLC	1,9961,996	$8,243	0.00%	TRIM -28%
66	PNC FINANCIAL SERVICES GROUP, INC.	1,7591,759	$7,265	0.00%	—
67	State of Wyoming	1,0651,065	$4,398	0.00%	NEW
68	Russell Investments Group, Ltd.	729729	$3,011	0.00%	—
69	ACADIAN ASSET MANAGEMENT LLC	802802	$3,000	0.00%	NEW
70	GROUP ONE TRADING LLC	712712	$2,941	0.00%	TRIM -82%
71	Bleichroeder LP	595595	$2,457	0.00%	—
72	Farther Finance Advisors, LLC	331331	$1,440	0.00%	—
73	Allworth Financial LP	310310	$1,281	0.00%	TRIM -57%
74	Blue Trust, Inc.	284284	$1,173	0.00%	—
75	Tower Research Capital LLC (TRC)	180180	$743	0.00%	TRIM -98%
76	QUADRANT CAPITAL GROUP LLC	128128	$529	0.00%	NEW
77	Parallel Advisors, LLC	116116	$479	0.00%	NEW
78	SBI Securities Co., Ltd.	5454	$223	0.00%	ADD 8%
79	JONES FINANCIAL COMPANIES LLLP	3838	$154	0.00%	—
80	Rockefeller Capital Management L.P.	3333	$136	0.00%	—
81	JPMORGAN CHASE & CO	3333	$132	0.00%	TRIM -99%
82	HighMark Wealth Management LLC	66	$24	0.00%	—
83	NORTHWESTERN MUTUAL WEALTH MANAGEMENT CO	55	$21	0.00%	—
84	ROYAL BANK OF CANADA	115115	$0	0.00%	ADD 11%

† a filer this large appearing as NEW usually reflects a renamed or succeeded filing entity (the old name stops filing the same quarter) — not a brand-new position.

Rows rank by the value each filer reported — 13F filers price their own positions, so a holder with fewer shares can rank just above one with more.

Holder trends· top 15 holders · shares held over 6 quarters

green added · red trimmed

Holder

2024-Q4

2025-Q1

2025-Q2

2025-Q3

2025-Q4

2026-Q1

Latest value

MORGAN STANLEY

550K

570K

11K

8.2M

9.5M

$39M

Empery Asset Management, LP

—

9.0M

8.9M

$37M

FMR LLC

41K

—

8.5M

8.1M

$33M

Bain Capital Life Sciences Investors, LLC

16.9M

564K

2.4M

8.0M

$33M

Kalehua Capital Management LLC

—

3.7M

7.4M

$31M

PERCEPTIVE ADVISORS LLC

—

6.3M

6.7M

$28M

Saturn V Capital Management LP

—

5.8M

6.5M

$27M

Deep Track Capital, LP

—

1.1M

5.0M

6.3M

$26M

VANGUARD CAPITAL MANAGEMENT LLC

—

3.5M

$14M

BRAIDWELL LP

—

3.4M

3.3M

$14M

NEA Management Company, LLC

15.0M

500K

2.2M

3.2M

$13M

Rosalind Advisors, Inc.

—

1.5M

2.6M

3.2M

$13M

Blackstone Inc.

—

2.7M

$11M

Trails Edge Capital Partners, LP

—

2.6M

$11M

Nantahala Capital Management, LLC

—

2.2M

2.4M

$10M

Shares reported each quarter by the largest current holders. Green = added vs the prior filing, red = trimmed, grey = roughly held; a dash is a quarter with no 13F on file (a gap is skipped, not read as an exit). 13F is filed up to 45 days after quarter-end. Up to 40 quarters (10 years) available — use the selector above.

Institutional footprint by quarter

Line breaks are honest gaps — quarters with no 13F record, or a suppressed % — never interpolated. % of shares outstanding uses today's share count for every quarter (the only count stored).

Quarter	Holders	Shares held	% shares out	Value held
2026-Q1	84	98,479,119	104.4%	$407M
2025-Q4	79	89,427,070	94.8%	$358M
2025-Q3	42	16,159,404	17.1%	$55M
2025-Q2	52	2,807,320	3.0%	$5M
2025-Q1	94	98,662,404	104.6%	$24M
2024-Q4	90	99,849,339	105.9%	$73M
2024-Q3	98	100,666,124	106.7%	$67M
2024-Q2	99	104,689,286	—	$61M

Short interest has its own tab now — open SI →

Source: SEC Form 13F — every institution manager (≥ $100M in 13F securities) reporting a long US-listed position, across ~10,250 filers over 10 years of history. 13F is long-only, US-listed, filed up to 45 days after quarter-end.

Institutional ownership· 13F filers holding XFOR · 2026-Q1 methodology → sources →

84 holders

% of shares outstanding held

104.4%

Shares held (13F)

98,479,119

Reporting holders

Top holders

largest 84 of 84 · Δ vs 2025-Q4

#	Holder	Shares	Value	% of shares out	Δ QoQ
1	MORGAN STANLEY	9,466,9929.5M	$39M	10.04%	ADD 15%
2	Empery Asset Management, LP	8,944,1188.9M	$37M	9.48%	—
3	FMR LLC	8,103,4008.1M	$33M	8.59%	TRIM -5%
4	Bain Capital Life Sciences Investors, LLC	7,967,4548.0M	$33M	8.45%	—
5	Kalehua Capital Management LLC	7,445,6807.4M	$31M	7.89%	ADD 100%
6	PERCEPTIVE ADVISORS LLC	6,737,6486.7M	$28M	7.14%	ADD 7%
7	Saturn V Capital Management LP	6,456,6466.5M	$27M	6.85%	ADD 11%
8	Deep Track Capital, LP	6,339,5356.3M	$26M	6.72%	ADD 26%
9	VANGUARD CAPITAL MANAGEMENT LLC	3,497,6123.5M	$14M	3.71%	NEW†
10	BRAIDWELL LP	3,272,9543.3M	$14M	3.47%	TRIM -3%
11	NEA Management Company, LLC	3,233,7433.2M	$13M	3.43%	—
12	Rosalind Advisors, Inc.	3,214,7663.2M	$13M	3.41%	ADD 23%
13	Blackstone Inc.	2,681,9222.7M	$11M	2.84%	—
14	Trails Edge Capital Partners, LP	2,571,4782.6M	$11M	2.73%	—
15	Nantahala Capital Management, LLC	2,449,4682.4M	$10M	2.60%	—
16	BVF INC/IL	2,233,7422.2M	$9M	2.37%	—
17	SAMSARA BIOCAPITAL, LLC	1,832,5661.8M	$8M	1.94%	TRIM -7%
18	STEMPOINT CAPITAL LP	1,701,4841.7M	$7M	1.80%	ADD 89%
19	BlackRock, Inc.	1,211,7941.2M	$5M	1.28%	—
20	MILLENNIUM MANAGEMENT LLC	1,210,5141.2M	$5M	1.28%	ADD 2062%
21	Woodline Partners LP	1,001,0951.0M	$4M	1.06%	—
22	GEODE CAPITAL MANAGEMENT, LLC	939,726939,726	$4M	1.00%	—
23	GOLDMAN SACHS GROUP INC	882,134882,134	$4M	0.94%	ADD 6%
24	SUSQUEHANNA INTERNATIONAL GROUP, LLP	856,222856,222	$4M	0.91%	ADD 3768%
25	VANGUARD FIDUCIARY TRUST CO	480,733480,733	$2M	0.51%	NEW
26	STATE STREET CORP	403,534403,534	$2M	0.43%	ADD 104%
27	MARSHALL WACE, LLP	336,834336,834	$1M	0.36%	ADD 319%
28	Stonepine Capital Management, LLC	335,309335,309	$1M	0.36%	TRIM -44%
29	Venrock Adviser, LLC	330,525330,525	$1M	0.35%	NEW
30	UBS Group AG	267,340267,340	$1M	0.28%	ADD 6375%
31	ACORN CAPITAL ADVISORS, LLC	234,039234,039	$966,583	0.25%	TRIM -14%
32	Qube Research & Technologies Ltd	218,954218,954	$904,280	0.23%	ADD 223%
33	NORTHERN TRUST CORP	178,235178,235	$736,111	0.19%	—
34	Pale Fire Capital SE	167,590167,590	$692,147	0.18%	—
35	BANK OF AMERICA CORP /DE/	150,676150,676	$622,292	0.16%	ADD 321%
36	Affinity Asset Advisors, LLC	145,000145,000	$598,850	0.15%	—
37	Palumbo Wealth Management LLC	131,014131,014	$541,088	0.14%	ADD 16%
38	Brevan Howard Capital Management LP	127,321127,321	$525,836	0.13%	NEW
39	Susquehanna Portfolio Strategies, LLC	102,599102,599	$423,734	0.11%	ADD 137%
40	Dynamic Technology Lab Private Ltd	36,22136,221	$384,667	0.04%	NEW
41	CHARLES SCHWAB INVESTMENT MANAGEMENT INC	66,74966,749	$275,673	0.07%	—
42	OMERS ADMINISTRATION Corp	57,30057,300	$236,649	0.06%	TRIM -48%
43	Hudson Bay Capital Management LP	50,28750,287	$207,685	0.05%	ADD 56%
44	Catalyst Funds Management Pty Ltd	47,38347,383	$195,692	0.05%	NEW
45	JANE STREET GROUP, LLC	37,14337,143	$153,401	0.04%	TRIM -59%
46	CITIGROUP INC	35,76535,765	$147,709	0.04%	ADD 11%
47	Vanguard Global Advisers, LLC	32,97732,977	$136,195	0.03%	NEW
48	Diametric Capital, LP	28,97328,973	$119,658	0.03%	NEW
49	STIFEL FINANCIAL CORP	21,78921,789	$89,989	0.02%	ADD 6%
50	Invesco Ltd.	19,96819,968	$82,468	0.02%	NEW
51	Schonfeld Strategic Advisors LLC	19,51419,514	$80,592	0.02%	NEW
52	Jefferies Financial Group Inc.	19,47419,474	$80,428	0.02%	TRIM -25%
53	CAXTON CORP	15,55715,557	$64,249	0.02%	—
54	ExodusPoint Capital Management, LP	14,70314,703	$60,723	0.02%	TRIM -81%
55	TWO SIGMA INVESTMENTS, LP	13,86813,868	$57,275	0.01%	TRIM -20%
56	Creative Planning	13,81913,819	$57,072	0.01%	TRIM -16%
57	Virtu Financial LLC	12,73012,730	$53,000	0.01%	TRIM -43%
58	Jump Financial, LLC	12,31712,317	$50,869	0.01%	NEW
59	Vanguard Personalized Indexing Management, LLC	11,52511,525	$47,598	0.01%	NEW
60	SummitTX Capital, L.P.	11,20011,200	$46,256	0.01%	NEW
61	WINTON GROUP Ltd	10,60010,600	$43,778	0.01%	NEW
62	Indivisible Partners	10,00010,000	$37,000	0.01%	—
63	BNP PARIBAS FINANCIAL MARKETS	4,7564,756	$19,642	0.01%	ADD 831%
64	BARCLAYS PLC	2,8142,814	$11,622	0.00%	TRIM -95%
65	SIGNATUREFD, LLC	1,9961,996	$8,243	0.00%	TRIM -28%
66	PNC FINANCIAL SERVICES GROUP, INC.	1,7591,759	$7,265	0.00%	—
67	State of Wyoming	1,0651,065	$4,398	0.00%	NEW
68	Russell Investments Group, Ltd.	729729	$3,011	0.00%	—
69	ACADIAN ASSET MANAGEMENT LLC	802802	$3,000	0.00%	NEW
70	GROUP ONE TRADING LLC	712712	$2,941	0.00%	TRIM -82%
71	Bleichroeder LP	595595	$2,457	0.00%	—
72	Farther Finance Advisors, LLC	331331	$1,440	0.00%	—
73	Allworth Financial LP	310310	$1,281	0.00%	TRIM -57%
74	Blue Trust, Inc.	284284	$1,173	0.00%	—
75	Tower Research Capital LLC (TRC)	180180	$743	0.00%	TRIM -98%
76	QUADRANT CAPITAL GROUP LLC	128128	$529	0.00%	NEW
77	Parallel Advisors, LLC	116116	$479	0.00%	NEW
78	SBI Securities Co., Ltd.	5454	$223	0.00%	ADD 8%
79	JONES FINANCIAL COMPANIES LLLP	3838	$154	0.00%	—
80	Rockefeller Capital Management L.P.	3333	$136	0.00%	—
81	JPMORGAN CHASE & CO	3333	$132	0.00%	TRIM -99%
82	HighMark Wealth Management LLC	66	$24	0.00%	—
83	NORTHWESTERN MUTUAL WEALTH MANAGEMENT CO	55	$21	0.00%	—
84	ROYAL BANK OF CANADA	115115	$0	0.00%	ADD 11%

† a filer this large appearing as NEW usually reflects a renamed or succeeded filing entity (the old name stops filing the same quarter) — not a brand-new position.

Rows rank by the value each filer reported — 13F filers price their own positions, so a holder with fewer shares can rank just above one with more.

Holder trends· top 15 holders · shares held over 6 quarters

green added · red trimmed

Holder

2024-Q4

2025-Q1

2025-Q2

2025-Q3

2025-Q4

2026-Q1

Latest value

MORGAN STANLEY

550K

570K

11K

8.2M

9.5M

$39M

Empery Asset Management, LP

—

9.0M

8.9M

$37M

FMR LLC

41K

—

8.5M

8.1M

$33M

Bain Capital Life Sciences Investors, LLC

16.9M

564K

2.4M

8.0M

$33M

Kalehua Capital Management LLC

—

3.7M

7.4M

$31M

PERCEPTIVE ADVISORS LLC

—

6.3M

6.7M

$28M

Saturn V Capital Management LP

—

5.8M

6.5M

$27M

Deep Track Capital, LP

—

1.1M

5.0M

6.3M

$26M

VANGUARD CAPITAL MANAGEMENT LLC

—

3.5M

$14M

BRAIDWELL LP

—

3.4M

3.3M

$14M

NEA Management Company, LLC

15.0M

500K

2.2M

3.2M

$13M

Rosalind Advisors, Inc.

—

1.5M

2.6M

3.2M

$13M

Blackstone Inc.

—

2.7M

$11M

Trails Edge Capital Partners, LP

—

2.6M

$11M

Nantahala Capital Management, LLC

—

2.2M

2.4M

$10M

Institutional footprint by quarter

Line breaks are honest gaps — quarters with no 13F record, or a suppressed % — never interpolated. % of shares outstanding uses today's share count for every quarter (the only count stored).

Quarter	Holders	Shares held	% shares out	Value held
2026-Q1	84	98,479,119	104.4%	$407M
2025-Q4	79	89,427,070	94.8%	$358M
2025-Q3	42	16,159,404	17.1%	$55M
2025-Q2	52	2,807,320	3.0%	$5M
2025-Q1	94	98,662,404	104.6%	$24M
2024-Q4	90	99,849,339	105.9%	$73M
2024-Q3	98	100,666,124	106.7%	$67M
2024-Q2	99	104,689,286	—	$61M

Short interest has its own tab now — open SI →

XFOR US Equity☆

Institutional ownership· 13F filers holding XFOR · 2026-Q1 methodology → sources →

Top holders

Holder trends· top 15 holders · shares held over 6 quarters

Institutional footprint by quarter

Institutional ownership· 13F filers holding XFOR · 2026-Q1 methodology → sources →

Top holders

Holder trends· top 15 holders · shares held over 6 quarters

Institutional footprint by quarter

XFOR US Equity