Who owns STRO (STRO)
Which tracked institutional funds hold STRO, how they are positioned, and who is buying versus exiting — from SEC Form 13F-HR filings. See STRO company fundamentals →
Ownership as of the 2026-Q1 13F filings. 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 STRO is one-sided between 2025-Q4 and 2026-Q1: 40 added or opened and 6 trimmed or exited — on balance accumulating.
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
STRO’s largest tracked holder by dollar value, BVF INC/IL, sizes it at 1.0% of its own reported 13F book, while the median holder sizes it at 0.0% of theirs — a 1.0pp conviction gap — its largest holder concentrates the name more heavily than the typical one.
Book-share is each fund’s reported value in STRO 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 2025-Q4 and 2026-Q1, across 78 tracked filers holding STRO, 50 increased or opened the position and 23 reduced or closed it; over the same quarter, there were no open-market insider Form 4s.
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 STRO between the 2025-Q4 and 2026-Q1 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 13
- BVF INC/IL$31M
- ORBIMED ADVISORS LLC$20M
- VANGUARD CAPITAL MANAGEMENT LLC$18M
- PERCEPTIVE ADVISORS LLC$18M
- RA CAPITAL MANAGEMENT, L.P.$18M
- EVENTIDE ASSET MANAGEMENT, LLC$18M
Full exits 4
- VANGUARD GROUP INC$4M
- Vestal Point Capital, LP$3M
- TANG CAPITAL MANAGEMENT LLC$2M
- Spruce Street Capital LP$875K
Largest adds
- SAMSARA BIOCAPITAL, LLC$24M
- Affinity Asset Advisors, LLC$18M
- Kynam Capital Management, LP$16M
- Point72 Asset Management, L.P.$15M
- ADAR1 Capital Management, LLC$12M
- UBS Group AG$10M
Largest trims
- Eversept Partners, LP$417K
- GSA CAPITAL PARTNERS LLP$388K
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 |
|---|---|---|---|---|
| BVF INC/IL trimmed | 1,251,788 | $31M | 8.3% | 2026-Q1 |
| Affinity Asset Advisors, LLC added | 1,069,519 | $27M | 7.1% | 2026-Q1 |
| SAMSARA BIOCAPITAL, LLC added | 1,062,872 | $26M | 7.0% | 2026-Q1 |
| Kynam Capital Management, LP added | 872,558 | $22M | 5.8% | 2026-Q1 |
| ORBIMED ADVISORS LLC added | 801,144 | $20M | 5.3% | 2026-Q1 |
| VANGUARD CAPITAL MANAGEMENT LLC new | 720,442 | $18M | 4.8% | 2026-Q1 |
| EVENTIDE ASSET MANAGEMENT, LLC trimmed | 715,307 | $18M | 4.7% | 2026-Q1 |
| RA CAPITAL MANAGEMENT, L.P. trimmed | 715,307 | $18M | 4.7% | 2026-Q1 |
| PERCEPTIVE ADVISORS LLC new | 715,307 | $18M | 4.7% | 2026-Q1 |
| Point72 Asset Management, L.P. added | 692,111 | $17M | 4.6% | 2026-Q1 |
| ADAR1 Capital Management, LLC added | 524,441 | $13M | 3.5% | 2026-Q1 |
| Velan Capital Investment Management LP added | 512,160 | $13M | 3.4% | 2026-Q1 |
| BALYASNY ASSET MANAGEMENT L.P. added | 465,792 | $12M | 3.1% | 2026-Q1 |
| Woodline Partners LP added | 457,441 | $11M | 3.0% | 2026-Q1 |
| UBS Group AG added | 392,871 | $10M | 2.6% | 2026-Q1 |
| ACADIAN ASSET MANAGEMENT LLC trimmed | 335,813 | $8M | 2.2% | 2026-Q1 |
| Merck & Co., Inc. | 272,351 | $7M | 1.8% | 2026-Q1 |
| ACUTA CAPITAL PARTNERS, LLC added | 269,425 | $7M | 1.8% | 2026-Q1 |
| BlackRock, Inc. added | 232,684 | $6M | 1.5% | 2026-Q1 |
| KVP Capital Advisors, LP new | 226,575 | $6M | 1.5% | 2026-Q1 |
| MARSHALL WACE, LLP added | 222,634 | $6M | 1.5% | 2026-Q1 |
| MILLENNIUM MANAGEMENT LLC trimmed | 210,378 | $5M | 1.4% | 2026-Q1 |
| ADAGE CAPITAL PARTNERS GP, L.L.C. | 200,000 | $5M | 1.3% | 2026-Q1 |
| Opaleye Management Inc. | 190,671 | $5M | 1.3% | 2026-Q1 |
| GEODE CAPITAL MANAGEMENT, LLC added | 171,386 | $4M | 1.1% | 2026-Q1 |
| CITADEL ADVISORS LLC added | 117,537 | $3M | 0.8% | 2026-Q1 |
| RENAISSANCE TECHNOLOGIES LLC trimmed | 97,824 | $2M | 0.6% | 2026-Q1 |
| VANGUARD FIDUCIARY TRUST CO new | 94,838 | $2M | 0.6% | 2026-Q1 |
| SUSQUEHANNA INTERNATIONAL GROUP, LLP trimmed | 84,902 | $2M | 0.6% | 2026-Q1 |
| Eversept Partners, LP trimmed | 73,161 | $2M | 0.5% | 2026-Q1 |
| Burkehill Global Management, LP new | 71,530 | $2M | 0.5% | 2026-Q1 |
| TWO SIGMA INVESTMENTS, LP added | 65,176 | $2M | 0.4% | 2026-Q1 |
| STATE STREET CORP added | 52,118 | $1M | 0.3% | 2026-Q1 |
| Fisher Asset Management, LLC trimmed | 35,295 | $879K | 0.2% | 2026-Q1 |
| Trexquant Investment LP added | 34,343 | $855K | 0.2% | 2026-Q1 |
| NORTHERN TRUST CORP added | 33,166 | $826K | 0.2% | 2026-Q1 |
| JANE STREET GROUP, LLC added | 27,760 | $692K | 0.2% | 2026-Q1 |
| GOLDMAN SACHS GROUP INC added | 27,187 | $677K | 0.2% | 2026-Q1 |
| GSA CAPITAL PARTNERS LLP trimmed | 25,822 | $643K | 0.2% | 2026-Q1 |
| STEMPOINT CAPITAL LP new | 23,295 | $580K | 0.2% | 2026-Q1 |
| BANK OF AMERICA CORP /DE/ added | 18,873 | $470K | 0.1% | 2026-Q1 |
| CITIGROUP INC added | 18,845 | $469K | 0.1% | 2026-Q1 |
| Brevan Howard Capital Management LP new | 18,791 | $468K | 0.1% | 2026-Q1 |
| AJU IB Investment Co., Ltd. | 17,500 | $436K | 0.1% | 2026-Q1 |
| Invesco Ltd. added | 17,165 | $428K | 0.1% | 2026-Q1 |
| RBF Capital, LLC | 15,272 | $380K | 0.1% | 2026-Q1 |
| Hudson Bay Capital Management LP trimmed | 14,768 | $368K | 0.1% | 2026-Q1 |
| Sigma Planning Corp new | 12,520 | $312K | 0.1% | 2026-Q1 |
| Jump Financial, LLC trimmed | 12,385 | $309K | 0.1% | 2026-Q1 |
| CHARLES SCHWAB INVESTMENT MANAGEMENT INC trimmed | 10,577 | $263K | 0.1% | 2026-Q1 |
| MORGAN STANLEY trimmed | 10,529 | $262K | 0.1% | 2026-Q1 |
| OMERS ADMINISTRATION Corp trimmed | 8,700 | $217K | 0.1% | 2026-Q1 |
| AQR CAPITAL MANAGEMENT LLC trimmed | 8,605 | $214K | 0.1% | 2026-Q1 |
| XTX Topco Ltd trimmed | 8,203 | $204K | 0.1% | 2026-Q1 |
| Persistent Asset Partners Ltd new | 7,411 | $185K | 0.0% | 2026-Q1 |
| State of Tennessee, Department of Treasury | 7,400 | $184K | 0.0% | 2026-Q1 |
| Vanguard Global Advisers, LLC new | 7,182 | $179K | 0.0% | 2026-Q1 |
| OSAIC HOLDINGS, INC. trimmed | 1,280 | $32K | 0.0% | 2026-Q1 |
| FMR LLC trimmed | 1,050 | $26K | 0.0% | 2026-Q1 |
| SUVRETTA CAPITAL MANAGEMENT, LLC | 6,488,324 | $6M | 1.5% | 2025-Q3 stale |
| VANGUARD GROUP INC trimmed | 375,786 | $4M | 1.2% | 2025-Q4 stale |
| Vestal Point Capital, LP trimmed | 243,000 | $3M | 0.7% | 2025-Q4 stale |
| TANG CAPITAL MANAGEMENT LLC trimmed | 139,617 | $2M | 0.4% | 2025-Q4 stale |
| Spruce Street Capital LP new | 75,594 | $875K | 0.2% | 2025-Q4 stale |
| JACOBS LEVY EQUITY MANAGEMENT, INC trimmed | 445,750 | $387K | 0.1% | 2025-Q3 stale |
| DAFNA Capital Management LLC | 437,079 | $380K | 0.1% | 2025-Q3 stale |
| CANTOR FITZGERALD, L. P. new | 500,000 | $357K | 0.1% | 2025-Q2 stale |
| Shay Capital LLC trimmed | 24,255 | $281K | 0.1% | 2025-Q4 stale |
| TWO SIGMA ADVISERS, LP trimmed | 17,580 | $203K | 0.1% | 2025-Q4 stale |
| Nuveen, LLC new | 290,897 | $189K | 0.1% | 2025-Q1 stale |
| DIMENSIONAL FUND ADVISORS LP trimmed | 197,516 | $172K | 0.0% | 2025-Q3 stale |
| Bank of New York Mellon Corp trimmed | 209,222 | $136K | 0.0% | 2025-Q1 stale |
| LPL Financial LLC trimmed | 142,883 | $124K | 0.0% | 2025-Q3 stale |
| D. E. Shaw & Co., Inc. added | 158,037 | $103K | 0.0% | 2025-Q1 stale |
| STRS OHIO | 152,800 | $99K | 0.0% | 2025-Q1 stale |
| PANAGORA ASSET MANAGEMENT INC trimmed | 140,362 | $91K | 0.0% | 2025-Q1 stale |
| EXCHANGE TRADED CONCEPTS, LLC added | 136,623 | $89K | 0.0% | 2025-Q1 stale |
| RHUMBLINE ADVISERS trimmed | 122,816 | $80K | 0.0% | 2025-Q1 stale |
| ALLIANCEBERNSTEIN L.P. | 96,370 | $63K | 0.0% | 2025-Q1 stale |
| State of Wyoming added | 94,932 | $62K | 0.0% | 2025-Q1 stale |
| HRT FINANCIAL LP added | 85,509 | $61K | 0.0% | 2025-Q2 stale |
| Jain Global LLC new | 84,472 | $60K | 0.0% | 2025-Q2 stale |
| Aberdeen Group plc | 69,389 | $60K | 0.0% | 2025-Q3 stale |
| Cerity Partners LLC trimmed | 68,061 | $59K | 0.0% | 2025-Q3 stale |
| Qube Research & Technologies Ltd trimmed | 65,226 | $57K | 0.0% | 2025-Q3 stale |
| Catalyst Funds Management Pty Ltd added | 63,776 | $55K | 0.0% | 2025-Q3 stale |
| SG Americas Securities, LLC added | 84,907 | $55K | 0.0% | 2025-Q1 stale |
| Vanguard Personalized Indexing Management, LLC trimmed | 60,184 | $52K | 0.0% | 2025-Q3 stale |
| IEQ CAPITAL, LLC trimmed | 59,752 | $52K | 0.0% | 2025-Q3 stale |
| Y-Intercept (Hong Kong) Ltd added | 66,591 | $48K | 0.0% | 2025-Q2 stale |
| INTECH INVESTMENT MANAGEMENT LLC added | 72,540 | $47K | 0.0% | 2025-Q1 stale |
| Vontobel Holding Ltd. | 50,000 | $43K | 0.0% | 2025-Q3 stale |
| ALPS ADVISORS INC trimmed | 61,267 | $40K | 0.0% | 2025-Q1 stale |
| BRIDGEWAY CAPITAL MANAGEMENT, LLC added | 42,900 | $37K | 0.0% | 2025-Q3 stale |
| SEI INVESTMENTS CO | 56,347 | $37K | 0.0% | 2025-Q1 stale |
| MIRAE ASSET GLOBAL ETFS HOLDINGS Ltd. added | 48,998 | $32K | 0.0% | 2025-Q1 stale |
| PRUDENTIAL FINANCIAL INC | 35,500 | $31K | 0.0% | 2025-Q3 stale |
| BLUEFIN CAPITAL MANAGEMENT, LLC new | 34,934 | $30K | 0.0% | 2025-Q3 stale |
| Point72 Asia (Singapore) Pte. Ltd. trimmed | 31,026 | $27K | 0.0% | 2025-Q3 stale |
| Corebridge Financial, Inc. trimmed | 40,104 | $26K | 0.0% | 2025-Q1 stale |
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.