48% buyers of institutions opening or closing positions this quarter
1 more exits than new buyers, ownership fell 9.71 percentage points vs the prior quarter, and 3 well-known fund managers in the top 25.
48% buyers of institutions opening or closing positions this quarter
60.7% institutional ownership
REGENERON PHARMACEUTICALS, INC. portfolio allocation
Institutional ownership vs Biotechnology peers
No Form 4 insider transactions on file
Latest positioning in ACET across 13F flow, ownership shift, marquee holders, and holder-count growth.
Ranked by reported Q1 2026 13F market value
Share of total reported institutional value in ACET held by the largest 10 / 25 filers.
| # | Institution | Shares Held | Market Value | QoQ Change | Ownership % | % of Fund |
|---|---|---|---|---|---|---|
| 1 | RA CAPITAL MANAGEMENT, L.P. | 1.2M | $8.1M | +24.7% | 12.651% | 0.09% |
| 2 | ORBIMED ADVISORS LLC | 1.0M | $7.0M | 0.0% | 10.996% | 0.14% |
| 3 | FRANKLIN RESOURCES INC | 627K | $4.3M | 0.0% | 6.703% | 0.00% |
| 4 | CITADEL ADVISORS LLC | 382K | $2.6M | +254.2% | 4.084% | 0.00% |
| 5 | VANGUARD CAPITAL MANAGEMENT LLC | 337K | $2.3M | β | 3.600% | 0.00% |
| 6 | Woodline Partners LP | 313K | $2.1M | -49.9% | 3.350% | 0.01% |
| 7 | ADAGE CAPITAL PARTNERS GP, L.L.C. | 274K | $1.9M | 0.0% | 2.935% | 0.00% |
| 8 | Prosight Management, LP | 250K | $1.7M | 0.0% | 2.677% | 0.28% |
| 9 | RENAISSANCE TECHNOLOGIES LLC | 233K | $1.6M | -4.3% | 2.488% | 0.00% |
| 10 | Stonepine Capital Management, LLC | 222K | $1.5M | +0.9% | 2.374% | 0.61% |
| 11 | Alyeska Investment Group, L.P. | 204K | $1.4M | 0.0% | 2.180% | 0.00% |
| 12 | Carlyle Group Inc. | 184K | $1.3M | 0.0% | 1.971% | 0.01% |
| 13 | NEXTBio Capital Management LP | 158K | $1.1M | 0.0% | 1.688% | 0.50% |
| 14 | GEODE CAPITAL MANAGEMENT, LLC | 101K | $689K | +13.8% | 1.082% | 0.00% |
| 15 | DAFNA Capital Management LLC | 94K | $639K | 0.0% | 1.004% | 0.15% |
| 16 | Burkehill Global Management, LP | 63K | $426K | 0.0% | 0.669% | 0.02% |
| 17 | REGENERON PHARMACEUTICALS, INC. | 61K | $412K | 0.0% | 0.647% | 0.86% |
| 18 | Rangeley Capital, LLC | 56K | $381K | +124.0% | 0.599% | 0.37% |
| 19 | ADAR1 Capital Management, LLC | 54K | $367K | -58.2% | 0.576% | 0.02% |
| 20 | VANGUARD FIDUCIARY TRUST CO | 50K | $343K | β | 0.538% | 0.00% |
| 21 | Trexquant Investment LP | 44K | $297K | β | 0.467% | 0.00% |
| 22 | TWO SIGMA INVESTMENTS, LP | 43K | $294K | -70.2% | 0.461% | 0.00% |
| 23 | RBF Capital, LLC | 39K | $263K | 0.0% | 0.413% | 0.01% |
| 24 | UBS Group AG | 38K | $261K | +910.5% | 0.410% | 0.00% |
| 25 | JANE STREET GROUP, LLC | 37K | $253K | β | 0.397% | 0.00% |
denotes a marquee investor (Buffett, Burry, ARK, Tiger Global, Pershing Square, Baupost and other widely-followed managers). β% of Fundβ shows how much of that investorβs total 13F portfolio is invested in ACET β a direct measure of their conviction.
Filings activity in ACET during Q1 2026, grouped by how each filer changed its position.
Institutions that opened a new ACET position in Q1 2026
Institutions that fully closed their ACET position in Q1 2026
8 quarters of 13F filings Β· Ξ columns show change vs prior quarter
| Quarter | Inst. Holders | Ξ Holders | Ownership % | Ξ Ownership | Total 13F Value | Ξ Value |
|---|---|---|---|---|---|---|
| Q1 2026 | 48 | 2.0% | 60.74% | 9.71 pp | $43M | 22% |
| Q4 2025 | 49 | 7.5% | 70.45% | +19.50 pp | $55M | +38% |
| Q3 2025 | 53 | +8.2% | 50.95% | +12.26 pp | $40M | +32% |
| Q2 2025 | 49 | 13% | 38.69% | 17.32 pp | $30M | 24% |
| Q1 2025 | 56 | 13% | 56.01% | 143.98 pp | $40M | 91% |
| Q4 2024 | 64 | +3.2% | 199.99% | +98.88 pp | $452M | +474% |
| Q3 2024 | 62 | 28% | 101.11% | +4.29 pp | $79M | +4.4% |
| Q2 2024 | 86 | β | 96.82% | β | $75M | β |
Source: SEC 13F institutional filings. Ownership % requires market cap data and will show once linked. Ξ columns compare to the immediately prior filed quarter.
No recent Form 4 insider transactions on file for ACET.
Quick answers to the most common questions about buying ACET stock.
Based on Q1 2026 13F filings, institutional ownership of Adicet Bio, Inc. stands at 60.7%, held across 48 reporting institutions.
RA CAPITAL MANAGEMENT, L.P. is the largest reported institutional holder of ACET, with approximately 1,182,624 shares worth $0.01B as of Q1 2026.
Yes β 3 widely-followed marquee investors appear among the top 25 institutional holders of ACET, including CITADEL ADVISORS LLC, RENAISSANCE TECHNOLOGIES LLC, TWO SIGMA INVESTMENTS, LP.
Our composite Smart Money Score for ACET is 46 out of 100 (Neutral). It combines net institutional buying activity, ownership shift, marquee investor presence, and holder-count growth.
12 institutions opened new positions in ACET during Q1 2026, while 13 fully exited. 8 added to existing positions and 28 trimmed.
ACET institutional ownership fell by 9.71 percentage points quarter-over-quarter, with a net change of -1 holders.
The top 10 institutions account for 77.0% of all reported 13F value in ACET, and the top 25 account for 96.5%.
All data is sourced from SEC Form 13F filings, which institutional investment managers with at least $100M in assets are required to file each quarter. We process every 13F filing from EDGAR and recompute the aggregates after each cycle. Insider transactions are sourced from Form 4 filings.