Who owns Werewolf Therapeutics (HOWL)
Which tracked institutional funds hold HOWL, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See HOWL 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
The tracked-fund tape on HOWL is one-sided between 2026-Q1 and 2026-Q2: 1 added or opened and 6 trimmed or exited — on balance reducing.
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
HOWL’s largest tracked holder by dollar value, MPM ASSET MANAGEMENT LLC, sizes it at 19.1% of its own reported 13F book, while the median holder sizes it at 0.0% of theirs — a 19.1pp conviction gap — its largest holder concentrates the name more heavily than the typical one.
Book-share is each fund’s reported value in HOWL 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 42 tracked filers holding HOWL, 16 increased or opened the position and 20 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 HOWL 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 1
- BALYASNY ASSET MANAGEMENT L.P.$644K
Largest trims
- RA CAPITAL MANAGEMENT, L.P.$5M
- MPM BIOIMPACT LLC$978K
- VANGUARD CAPITAL MANAGEMENT LLC$576K
- Lynx1 Capital Management LP$311K
- SPHERA FUNDS MANAGEMENT LTD.$296K
- DC Funds, LP$278K
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 |
|---|---|---|---|---|
| RA CAPITAL MANAGEMENT, L.P. trimmed | 2,387,744 | $859K | 5.5% | 2026-Q2 |
| BALYASNY ASSET MANAGEMENT L.P. new | 1,790,089 | $644K | 4.1% | 2026-Q2 |
| VANGUARD CAPITAL MANAGEMENT LLC | 1,217,976 | $438K | 2.8% | 2026-Q2 |
| RENAISSANCE TECHNOLOGIES LLC added | 674,632 | $243K | 1.6% | 2026-Q2 |
| Lynx1 Capital Management LP | 657,786 | $237K | 1.5% | 2026-Q2 |
| SPHERA FUNDS MANAGEMENT LTD. | 626,810 | $226K | 1.5% | 2026-Q2 |
| DC Funds, LP | 589,102 | $212K | 1.4% | 2026-Q2 |
| Verdad Advisers, LP added | 348,709 | $126K | 0.8% | 2026-Q2 |
| GEODE CAPITAL MANAGEMENT, LLC trimmed | 335,815 | $121K | 0.8% | 2026-Q2 |
| BANK OF AMERICA CORP /DE/ added | 311,502 | $112K | 0.7% | 2026-Q2 |
| XTX Topco Ltd added | 271,478 | $98K | 0.6% | 2026-Q2 |
| JANE STREET GROUP, LLC added | 251,837 | $91K | 0.6% | 2026-Q2 |
| UBS Group AG added | 215,838 | $78K | 0.5% | 2026-Q2 |
| VANGUARD FIDUCIARY TRUST CO | 157,726 | $57K | 0.4% | 2026-Q2 |
| STATE STREET CORP | 119,168 | $43K | 0.3% | 2026-Q2 |
| Squarepoint Ops LLC added | 103,242 | $37K | 0.2% | 2026-Q2 |
| Rangeley Capital, LLC new | 100,000 | $36K | 0.2% | 2026-Q2 |
| NORTHERN TRUST CORP | 86,851 | $31K | 0.2% | 2026-Q2 |
| Alyeska Investment Group, L.P. | 86,554 | $31K | 0.2% | 2026-Q2 |
| MPM BIOIMPACT LLC trimmed | 80,142 | $29K | 0.2% | 2026-Q2 |
| MILLENNIUM MANAGEMENT LLC trimmed | 62,055 | $22K | 0.1% | 2026-Q2 |
| TWO SIGMA INVESTMENTS, LP added | 27,300 | $10K | 0.1% | 2026-Q2 |
| StoneX Group Inc. added | 20,000 | $9K | 0.1% | 2026-Q2 |
| GOLDMAN SACHS GROUP INC trimmed | 20,023 | $7K | 0.0% | 2026-Q2 |
| MORGAN STANLEY trimmed | 19,108 | $7K | 0.0% | 2026-Q2 |
| CERTUITY, LLC | 15,000 | $5K | 0.0% | 2026-Q2 |
| HBK Sorce Advisory LLC | 13,227 | $5K | 0.0% | 2026-Q2 |
| BARCLAYS PLC | 13,235 | $5K | 0.0% | 2026-Q2 |
| Larson Financial Group LLC | 13,052 | $5K | 0.0% | 2026-Q2 |
| LPL Financial LLC added | 11,791 | $4K | 0.0% | 2026-Q2 |
| Ranch Capital Advisors Inc. trimmed | 11,000 | $4K | 0.0% | 2026-Q2 |
| Marest Capital, LLC new | 10,870 | $4K | 0.0% | 2026-Q2 |
| Cetera Investment Advisers | 10,200 | $4K | 0.0% | 2026-Q2 |
| Tower Research Capital LLC (TRC) added | 9,897 | $4K | 0.0% | 2026-Q2 |
| OSAIC HOLDINGS, INC. | 8,625 | $3K | 0.0% | 2026-Q2 |
| Financial Perspectives, Inc | 6,750 | $2K | 0.0% | 2026-Q2 |
| GROUP ONE TRADING LLC | 1,871 | $673 | 0.0% | 2026-Q2 |
| JPMORGAN CHASE & CO added | 2,108 | $650 | 0.0% | 2026-Q2 |
| BNP PARIBAS FINANCIAL MARKETS | 790 | $284 | 0.0% | 2026-Q2 |
| SIMPLEX TRADING, LLC trimmed | 255 | $91 | 0.0% | 2026-Q2 |
| SBI Securities Co., Ltd. added | 100 | $36 | 0.0% | 2026-Q2 |
| Optiver Holding B.V. | 22 | $8 | 0.0% | 2026-Q2 |
| Squadron Capital Management LLC new | 563,535 | $469K | 3.0% | 2026-Q1 stale (1 quarter behind) |
| BlackRock, Inc. trimmed | 101,608 | $85K | 0.5% | 2026-Q1 stale (1 quarter behind) |
| BRIDGEWAY CAPITAL MANAGEMENT, LLC | 77,000 | $64K | 0.4% | 2026-Q1 stale (1 quarter behind) |
| RAYMOND JAMES FINANCIAL INC added | 19,778 | $16K | 0.1% | 2026-Q1 stale (1 quarter behind) |
| HRT FINANCIAL LP trimmed | 17,861 | $14K | 0.1% | 2026-Q1 stale (1 quarter behind) |
| Delta Investment Management, LLC | 14,925 | $12K | 0.1% | 2026-Q1 stale (1 quarter behind) |
| CITADEL ADVISORS LLC trimmed | 10,382 | $9K | 0.1% | 2026-Q1 stale (1 quarter behind) |
| Vanguard Global Advisers, LLC new | 10,343 | $9K | 0.1% | 2026-Q1 stale (1 quarter behind) |
| TFC Financial Management, Inc. | 4,500 | $4K | 0.0% | 2026-Q1 stale (1 quarter behind) |
| CITIGROUP INC added | 3,384 | $3K | 0.0% | 2026-Q1 stale (1 quarter behind) |
| NORTHWESTERN MUTUAL WEALTH MANAGEMENT CO added | 200 | $167 | 0.0% | 2026-Q1 stale (1 quarter behind) |
| FMR LLC trimmed | 39 | $32 | 0.0% | 2026-Q1 stale (1 quarter behind) |
| Arax Advisory Partners trimmed | 12 | $32 | 0.0% | 2026-Q1 stale (1 quarter behind) |
| VANGUARD GROUP INC | 1,408,047 | $893K | 5.7% | 2025-Q4 stale (2 quarters behind) |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP added | 99,829 | $63K | 0.4% | 2025-Q4 stale (2 quarters behind) |
| Vontobel Holding Ltd. added | 60,003 | $38K | 0.2% | 2025-Q4 stale (2 quarters behind) |
| Regal Investment Advisors LLC added | 52,593 | $33K | 0.2% | 2025-Q4 stale (2 quarters behind) |
| EDGEWOOD MANAGEMENT LLC | 50,000 | $32K | 0.2% | 2025-Q4 stale (2 quarters behind) |
| Point72 Asset Management, L.P. trimmed | 14,483 | $9K | 0.1% | 2025-Q4 stale (2 quarters behind) |
| Engineers Gate Manager LP added | 12,185 | $8K | 0.0% | 2025-Q4 stale (2 quarters behind) |
| HIGHLINE WEALTH PARTNERS LLC added | 12,000 | $8K | 0.0% | 2025-Q4 stale (2 quarters behind) |
| TWO SIGMA ADVISERS, LP trimmed | 10,300 | $7K | 0.0% | 2025-Q4 stale (2 quarters behind) |
| FEDERATED HERMES, INC. | 4,387 | $3K | 0.0% | 2025-Q4 stale (2 quarters behind) |
| NISA INVESTMENT ADVISORS, LLC trimmed | 345 | $219 | 0.0% | 2025-Q4 stale (2 quarters behind) |
| ROYAL BANK OF CANADA trimmed | 62 | — | 0.0% | 2025-Q4 stale (2 quarters behind) |
| MPM ASSET MANAGEMENT LLC | 4,309,860 | $8M | 54.7% | 2025-Q3 stale (3 quarters behind) |
| PFM Health Sciences, LP | 401,110 | $790K | 5.1% | 2025-Q3 stale (3 quarters behind) |
| Cubist Systematic Strategies, LLC new | 46,711 | $92K | 0.6% | 2025-Q3 stale (3 quarters behind) |
| ACADIAN ASSET MANAGEMENT LLC trimmed | 34,285 | $67K | 0.4% | 2025-Q3 stale (3 quarters behind) |
| Qube Research & Technologies Ltd trimmed | 29,250 | $58K | 0.4% | 2025-Q3 stale (3 quarters behind) |
| AQR CAPITAL MANAGEMENT LLC trimmed | 17,807 | $35K | 0.2% | 2025-Q3 stale (3 quarters behind) |
| Point72 Asia (Singapore) Pte. Ltd. trimmed | 13,016 | $26K | 0.2% | 2025-Q3 stale (3 quarters behind) |
| Virtu Financial LLC new | 12,230 | $24K | 0.2% | 2025-Q3 stale (3 quarters behind) |
| CWM, LLC trimmed | 1,569 | $3K | 0.0% | 2025-Q3 stale (3 quarters behind) |
| Rossby Financial, LCC | 860 | $2K | 0.0% | 2025-Q3 stale (3 quarters behind) |
| Advisory Services Network, LLC new | 157 | $309 | 0.0% | 2025-Q3 stale (3 quarters behind) |
| Plante Moran Financial Advisors, LLC | 50 | $99 | 0.0% | 2025-Q3 stale (3 quarters behind) |
| EverSource Wealth Advisors, LLC trimmed | 35 | $69 | 0.0% | 2025-Q3 stale (3 quarters behind) |
| MARSHALL WACE, LLP new | 103,785 | $113K | 0.7% | 2025-Q2 stale (4 quarters behind) |
| Y-Intercept (Hong Kong) Ltd new | 84,421 | $92K | 0.6% | 2025-Q2 stale (4 quarters behind) |
| Jain Global LLC new | 26,983 | $29K | 0.2% | 2025-Q2 stale (4 quarters behind) |
| Quadrature Capital Ltd new | 25,791 | $28K | 0.2% | 2025-Q2 stale (4 quarters behind) |
| TWO SIGMA SECURITIES, LLC added | 22,409 | $24K | 0.2% | 2025-Q2 stale (4 quarters behind) |
| Jump Financial, LLC new | 11,345 | $12K | 0.1% | 2025-Q2 stale (4 quarters behind) |
| AVANTAX ADVISORY SERVICES, INC. new | 10,200 | $11K | 0.1% | 2025-Q2 stale (4 quarters behind) |
| WELLS FARGO & COMPANY/MN trimmed | 459 | $500 | 0.0% | 2025-Q2 stale (4 quarters behind) |
| Point72 (DIFC) Ltd added | 403 | $439 | 0.0% | 2025-Q2 stale (4 quarters behind) |
| Essential Partners LLC new | 52 | $57 | 0.0% | 2025-Q2 stale (4 quarters behind) |
| True Wealth Design, LLC trimmed | 13 | $15 | 0.0% | 2025-Q2 stale (4 quarters behind) |
| CONCOURSE FINANCIAL GROUP SECURITIES, INC. | 0 | — | 0.0% | 2025-Q2 stale (4 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.