Who owns X4 Pharmaceuticals (XFOR)
Which tracked institutional funds hold XFOR, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See XFOR company fundamentals →
Ownership as of the 2026-Q2 13F filings (latest filed 2026-09-22). 13F is disclosed up to 45 days after quarter-end, so the most recent quarter fills in over the following weeks.
How the tape is positioned
28 tracked funds added or opened XFOR while 13 trimmed or exited it between 2026-Q1 and 2026-Q2 — the tape is split. When large holders disagree on a name, the funds moving first are sometimes ahead of the story.
A prompt to read the filings, not a verdict. 13F is a quarter-end snapshot disclosed up to 45 days late; a fund adds or exits for mandate, benchmark, and timing reasons that have nothing to do with a view on the stock. This is a starting question, not a signal to trade.
Conviction spread
XFOR’s largest tracked holder by dollar value, MORGAN STANLEY, sizes it at 0.0% of its own reported 13F book, while the median holder sizes it at 0.0% of theirs — a 0.0pp conviction gap — its largest holder concentrates the name more heavily than the typical one.
Book-share is each fund’s reported value in XFOR divided by its whole reported 13F book, so it is comparable across funds of different sizes and is unaffected by stock splits. A higher share means a fund has committed more of its book to the name — a starting question about conviction, not a verdict or a signal to trade.
Institutional & insider positioning
Between 2026-Q1 and 2026-Q2, across 88 tracked filers holding XFOR, 55 increased or opened the position and 39 reduced or closed it; over the same quarter, open-market insider Form 4s were net sales.
This fuses two public signals for the same quarter — how tracked institutions changed their positions and whether insiders bought or sold in the open market. It describes what was filed; it is a starting question, not a verdict or a signal to trade.
New buyers & exits
Funds opening or closing a position in XFOR between the 2026-Q1 and 2026-Q2 13F filings, and the largest changes among funds holding it in both. New buyers and exits are counted on fund presence (split-invariant); adds and trims are measured on reported value.
New buyers 4
- VANGUARD PORTFOLIO MANAGEMENT LLC$3M
- Verdad Advisers, LP$2M
- Bank of New York Mellon Corp$917K
- Nuveen, LLC$502K
Full exits 7
- MILLENNIUM MANAGEMENT LLC$5M
- STEMPOINT CAPITAL LP$4M
- MARSHALL WACE, LLP$1M
- ACORN CAPITAL ADVISORS, LLC$967K
- Qube Research & Technologies Ltd$904K
- Pale Fire Capital SE$692K
Largest adds
- BlackRock, Inc.$21M
- PERCEPTIVE ADVISORS LLC$9M
- Venrock Adviser, LLC$8M
- GEODE CAPITAL MANAGEMENT, LLC$6M
- Saturn V Capital Management LP$6M
- FMR LLC$5M
Largest trims
- Empery Asset Management, LP$5M
- SUSQUEHANNA INTERNATIONAL GROUP, LLP$3M
- SAMSARA BIOCAPITAL, LLC$1M
- UBS Group AG$833K
- BANK OF AMERICA CORP /DE/$403K
- Stonepine Capital Management, LLC$334K
Institutional holders
One row per tracked fund, largest reported value first. “% of value” is the fund’s share of this security’s tracked institutional value — not of shares outstanding. Rows marked stale are from an earlier filing than the security’s latest quarter — that fund is absent from the newest snapshot (position exited, or reported under a different name).
| Fund | Shares | Reported value | % of value | Quarter |
|---|---|---|---|---|
| MORGAN STANLEY trimmed | 9,461,279 | $44M | 8.8% | 2026-Q2 |
| FMR LLC added | 8,321,657 | $39M | 7.8% | 2026-Q2 |
| Bain Capital Life Sciences Investors, LLC | 7,967,454 | $37M | 7.4% | 2026-Q2 |
| PERCEPTIVE ADVISORS LLC added | 7,933,491 | $37M | 7.4% | 2026-Q2 |
| Saturn V Capital Management LP added | 6,973,343 | $33M | 6.5% | 2026-Q2 |
| Empery Asset Management, LP trimmed | 6,930,591 | $32M | 6.5% | 2026-Q2 |
| Deep Track Capital, LP trimmed | 5,878,757 | $27M | 5.5% | 2026-Q2 |
| BlackRock, Inc. added | 5,554,906 | $26M | 5.2% | 2026-Q2 |
| Kalehua Capital Management LLC | 3,722,840 | $17M | 3.5% | 2026-Q2 |
| VANGUARD CAPITAL MANAGEMENT LLC added | 3,715,859 | $17M | 3.5% | 2026-Q2 |
| NEA Management Company, LLC | 3,233,743 | $15M | 3.0% | 2026-Q2 |
| Rosalind Advisors, Inc. | 3,214,766 | $15M | 3.0% | 2026-Q2 |
| BRAIDWELL LP trimmed | 2,922,754 | $14M | 2.7% | 2026-Q2 |
| Blackstone Inc. | 2,681,922 | $13M | 2.5% | 2026-Q2 |
| Trails Edge Capital Partners, LP | 2,571,478 | $12M | 2.4% | 2026-Q2 |
| Nantahala Capital Management, LLC | 2,449,468 | $11M | 2.3% | 2026-Q2 |
| BVF INC/IL | 2,233,742 | $10M | 2.1% | 2026-Q2 |
| GEODE CAPITAL MANAGEMENT, LLC added | 2,098,047 | $10M | 2.0% | 2026-Q2 |
| Venrock Adviser, LLC added | 1,934,253 | $9M | 1.8% | 2026-Q2 |
| SAMSARA BIOCAPITAL, LLC trimmed | 1,395,587 | $7M | 1.3% | 2026-Q2 |
| STATE STREET CORP added | 1,296,017 | $6M | 1.2% | 2026-Q2 |
| Woodline Partners LP | 1,001,095 | $5M | 0.9% | 2026-Q2 |
| GOLDMAN SACHS GROUP INC added | 916,536 | $4M | 0.9% | 2026-Q2 |
| NORTHERN TRUST CORP added | 652,849 | $3M | 0.6% | 2026-Q2 |
| VANGUARD FIDUCIARY TRUST CO added | 572,038 | $3M | 0.5% | 2026-Q2 |
| VANGUARD PORTFOLIO MANAGEMENT LLC new | 542,128 | $3M | 0.5% | 2026-Q2 |
| Verdad Advisers, LP new | 352,093 | $2M | 0.3% | 2026-Q2 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC added | 263,264 | $1M | 0.2% | 2026-Q2 |
| Stonepine Capital Management, LLC trimmed | 224,989 | $1M | 0.2% | 2026-Q2 |
| Bank of New York Mellon Corp trimmed | 196,340 | $917K | 0.2% | 2026-Q2 |
| Affinity Asset Advisors, LLC | 145,000 | $677K | 0.1% | 2026-Q2 |
| Nuveen, LLC new | 107,389 | $502K | 0.1% | 2026-Q2 |
| Invesco Ltd. added | 96,772 | $452K | 0.1% | 2026-Q2 |
| ALPS ADVISORS INC new | 95,726 | $447K | 0.1% | 2026-Q2 |
| RHUMBLINE ADVISERS trimmed | 95,081 | $444K | 0.1% | 2026-Q2 |
| Susquehanna Portfolio Strategies, LLC trimmed | 87,282 | $408K | 0.1% | 2026-Q2 |
| DEUTSCHE BANK AG\ trimmed | 78,885 | $368K | 0.1% | 2026-Q2 |
| AMERICAN CENTURY COMPANIES INC new | 74,795 | $349K | 0.1% | 2026-Q2 |
| CITIGROUP INC added | 70,112 | $327K | 0.1% | 2026-Q2 |
| WELLS FARGO & COMPANY/MN added | 67,712 | $316K | 0.1% | 2026-Q2 |
| Palumbo Wealth Management LLC trimmed | 67,116 | $313K | 0.1% | 2026-Q2 |
| Squarepoint Ops LLC added | 67,078 | $313K | 0.1% | 2026-Q2 |
| PRICE T ROWE ASSOCIATES INC /MD/ trimmed | 66,379 | $310K | 0.1% | 2026-Q2 |
| UBS Group AG trimmed | 58,043 | $271K | 0.1% | 2026-Q2 |
| WELLINGTON MANAGEMENT GROUP LLP new | 51,800 | $242K | 0.0% | 2026-Q2 |
| MetLife Investment Management, LLC new | 47,969 | $224K | 0.0% | 2026-Q2 |
| BANK OF AMERICA CORP /DE/ trimmed | 46,861 | $219K | 0.0% | 2026-Q2 |
| Point72 Asset Management, L.P. trimmed | 41,072 | $192K | 0.0% | 2026-Q2 |
| MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. trimmed | 37,073 | $173K | 0.0% | 2026-Q2 |
| Jump Financial, LLC added | 34,253 | $160K | 0.0% | 2026-Q2 |
| Vanguard Global Advisers, LLC | 32,977 | $154K | 0.0% | 2026-Q2 |
| JPMORGAN CHASE & CO added | 33,552 | $142K | 0.0% | 2026-Q2 |
| Police & Firemen's Retirement System of New Jersey trimmed | 23,846 | $111K | 0.0% | 2026-Q2 |
| AXQ CAPITAL, LP new | 22,880 | $107K | 0.0% | 2026-Q2 |
| MANUFACTURERS LIFE INSURANCE COMPANY, THE new | 22,083 | $103K | 0.0% | 2026-Q2 |
| BARCLAYS PLC added | 19,439 | $91K | 0.0% | 2026-Q2 |
| TWO SIGMA INVESTMENTS, LP added | 19,426 | $91K | 0.0% | 2026-Q2 |
| STIFEL FINANCIAL CORP trimmed | 18,519 | $86K | 0.0% | 2026-Q2 |
| RENAISSANCE TECHNOLOGIES LLC trimmed | 18,100 | $85K | 0.0% | 2026-Q2 |
| INTECH INVESTMENT MANAGEMENT LLC trimmed | 17,290 | $81K | 0.0% | 2026-Q2 |
| NEW YORK STATE COMMON RETIREMENT FUND trimmed | 16,500 | $77K | 0.0% | 2026-Q2 |
| BNP PARIBAS FINANCIAL MARKETS added | 16,384 | $77K | 0.0% | 2026-Q2 |
| VOYA INVESTMENT MANAGEMENT LLC trimmed | 15,838 | $74K | 0.0% | 2026-Q2 |
| CAXTON CORP | 15,557 | $73K | 0.0% | 2026-Q2 |
| WINTON GROUP Ltd added | 14,400 | $67K | 0.0% | 2026-Q2 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP trimmed | 14,050 | $66K | 0.0% | 2026-Q2 |
| Creative Planning added | 13,872 | $65K | 0.0% | 2026-Q2 |
| ALLIANCEBERNSTEIN L.P. trimmed | 14,580 | $60K | 0.0% | 2026-Q2 |
| PRUDENTIAL FINANCIAL INC new | 12,500 | $58K | 0.0% | 2026-Q2 |
| ProShare Advisors LLC trimmed | 10,588 | $49K | 0.0% | 2026-Q2 |
| Indivisible Partners | 10,000 | $47K | 0.0% | 2026-Q2 |
| Pettinga Financial Advisors LLC new | 10,000 | $47K | 0.0% | 2026-Q2 |
| Legal & General Group Plc trimmed | 7,858 | $37K | 0.0% | 2026-Q2 |
| Tower Research Capital LLC (TRC) added | 7,745 | $36K | 0.0% | 2026-Q2 |
| Ameritas Investment Partners, Inc. trimmed | 7,338 | $34K | 0.0% | 2026-Q2 |
| Russell Investments Group, Ltd. added | 7,178 | $34K | 0.0% | 2026-Q2 |
| ROYAL BANK OF CANADA added | 2,559 | $12K | 0.0% | 2026-Q2 |
| PNC Financial Services Group, Inc. | 1,759 | $8K | 0.0% | 2026-Q2 |
| Sterling Capital Management LLC added | 1,629 | $8K | 0.0% | 2026-Q2 |
| CALIFORNIA STATE TEACHERS RETIREMENT SYSTEM trimmed | 1,113 | $5K | 0.0% | 2026-Q2 |
| GROUP ONE TRADING LLC | 712 | $3K | 0.0% | 2026-Q2 |
| Bleichroeder LP | 595 | $3K | 0.0% | 2026-Q2 |
| Blue Trust, Inc. | 284 | $1K | 0.0% | 2026-Q2 |
| Rockefeller Capital Management L.P. | 33 | $154 | 0.0% | 2026-Q2 |
| JONES FINANCIAL COMPANIES LLLP | 38 | $153 | 0.0% | 2026-Q2 |
| Caitong International Asset Management Co., Ltd new | 30 | $140 | 0.0% | 2026-Q2 |
| SBI Securities Co., Ltd. trimmed | 9 | $42 | 0.0% | 2026-Q2 |
| HighMark Wealth Management LLC | 6 | $28 | 0.0% | 2026-Q2 |
| MILLENNIUM MANAGEMENT LLC added | 1,210,514 | $5M | 1.0% | 2026-Q1 stale (1 quarter behind) |
| STEMPOINT CAPITAL LP trimmed | 850,742 | $4M | 0.7% | 2026-Q1 stale (1 quarter behind) |
| MARSHALL WACE, LLP added | 336,834 | $1M | 0.3% | 2026-Q1 stale (1 quarter behind) |
| ACORN CAPITAL ADVISORS, LLC trimmed | 234,039 | $967K | 0.2% | 2026-Q1 stale (1 quarter behind) |
| Qube Research & Technologies Ltd added | 218,954 | $904K | 0.2% | 2026-Q1 stale (1 quarter behind) |
| Pale Fire Capital SE | 167,590 | $692K | 0.1% | 2026-Q1 stale (1 quarter behind) |
| Brevan Howard Capital Management LP new | 127,321 | $526K | 0.1% | 2026-Q1 stale (1 quarter behind) |
| VANGUARD GROUP INC added | 3,423,662 | $14M | 2.7% | 2025-Q4 stale (2 quarters behind) |
| Siren, L.L.C. new | 1,500,000 | $6M | 1.2% | 2025-Q4 stale (2 quarters behind) |
| SILVERARC CAPITAL MANAGEMENT, LLC new | 357,387 | $1M | 0.3% | 2025-Q4 stale (2 quarters behind) |
| KINGDON CAPITAL MANAGEMENT, L.L.C. added | 933,332 | $3M | 0.6% | 2025-Q3 stale (3 quarters behind) |
| BOOTHBAY FUND MANAGEMENT, LLC new | 343,963 | $1M | 0.2% | 2025-Q3 stale (3 quarters behind) |
Ownership over time
Tracked institutional holder count and total shares held by filing quarter (independent scales). The curated-era tail and any mid-ingest latest quarter are handled honestly — a partial quarter is not drawn as a collapse.
Reading this table
Funds hold the same stock for different reasons — an index fund “holds” almost everything, an active manager sizes a name to a mandate and a benchmark, and each fund entered at its own price and time. Because 13F is filed up to 45 days after quarter-end, every row is a backward-looking snapshot; a manager may have traded since. Share-class siblings (a company’s A and C shares) are rolled up to one line so a dual-class name is never double-counted. Compare like-for-like. A large holder is not an endorsement, and a fund exiting is not a warning — this is a starting question, not a verdict.
About 13F filings
A Form 13F is a quarterly disclosure that institutional investment managers with over $100 million in US-listed equities must file with the SEC. In plain English: it is a snapshot of the long stock positions a fund held at the end of a quarter. It covers long US-listed equities only — not short positions, options, cash, or private holdings — and the funds shown are the large sample we track, not the complete 13F universe.