Adicet Bio, Inc.
Adicet Bio, Inc. (ACET) Stock Ownership
Institutional vs insider vs public ownership from 13F and float data — top holders, activity, and insider trades below.
SEC 13F · FMP · ACET · as of Sep 30, 2025
Ownership Breakdown
54
Institutional Holders
▲ 6 vs Q2
$41.65M
Total Inst. Value
▲ $10.16M vs Q2
9.35M
Shares Outstanding
freeFloat 88.08%
51.40M
13F Shares Held
▼ 201,071 vs Q2
Institutional ownership = 13F shares ÷ total outstanding. Insider % = 100 − free float. Public % = free float − institution %. Data: FMP /symbol-positions-summary + /shares-float + SEC EDGAR.
Top Institutional Holders
ACET largest shareholders · institutional ownership
Q3 2025 · SEC 13F
Showing top 10 holders
| Holder | Shares | % Owned | Weight | Value | Reported | Change |
|---|---|---|---|---|---|---|
ORBIMED ADVISORS LLC pharmaceutical preparations | 11.45M | 12.57% | 12.57% | $9.27B | Nov 14, 2025 | — held |
TANG CAPITAL MANAGEMENT LLC pharmaceutical preparations | 8.22M | 9.03% | 9.03% | $6.66B | Nov 14, 2025 | — held |
RA CAPITAL MANAGEMENT, L.P. pharmaceutical preparations | 7.54M | 8.28% | 8.28% | $6.11B | Nov 14, 2025 | — held |
GOLDMAN SACHS GROUP INC pharmaceutical preparations | 3.75M | 4.12% | 4.12% | $3.04B | Nov 14, 2025 | ▼ 481 |
VANGUARD GROUP INC pharmaceutical preparations | 3.27M | 3.59% | 3.59% | $2.65B | Nov 7, 2025 | — held |
CARLYLE GROUP INC. pharmaceutical preparations | 2.95M | 3.24% | 3.24% | $2.39B | Nov 7, 2025 | — held |
ACADIAN ASSET MANAGEMENT LLC pharmaceutical preparations | 2.27M | 2.49% | 2.49% | $1.83B | Nov 13, 2025 | ▲ 190.9K |
RENAISSANCE TECHNOLOGIES LLC pharmaceutical preparations | 1.83M | 2.01% | 2.01% | $1.48B | Nov 13, 2025 | ▲ 675.1K |
REGENERON PHARMACEUTICALS, INC. pharmaceutical preparations | 968.2K | 1.06% | 1.06% | $784.42M | Nov 7, 2025 | — held |
BRIDGEWAY CAPITAL MANAGEMENT, LLC pharmaceutical preparations | 901.6K | 98.98% | 98.98% | $730.48M | Nov 14, 2025 | — held |
Data from SEC Form 13F filings. Ownership bar normalised to largest holder. Change flags: isNew / isSoldOut / changeInSharesNumber (FMP extract-analytics/holder).
Institutional Activity
Q3 2025 vs prior quarter
Q3 2025
16
Increased
+2.10M shares7
New Positions
first time holders10
Decreased
−1.73M shares0
Sold Out
fully exitedNet shares change (top 50)
+367.8K
+2.10M / −1.73M
Net new holders
+13
7 new / 0 exited
Based on top 50 institutional holders by position size. Fields: isNew, isSoldOut, changeInSharesNumber (FMP extract-analytics/holder, limit=50).
Insider Buying vs Selling
ACET insider trading · insider activity
Source: SEC Form 4
Insiders have been net buyers of shares recently. Selling may be driven by pre-scheduled Rule 10b5-1 plans rather than negative sentiment.
1
Buy transactions
5
Sell transactions
0.20
Buy/Sell ratio
$0M
Total disposed
Recent Insider Transactions
Showing 10 most recent · Common Stock only
| Name · Role | Date | Type | Shares | Price | Value | After Trans. | Filing |
|---|---|---|---|---|---|---|---|
RA CAPITAL MANAGEMENT, L.P. 10 percent owner | Apr 27, 2026 | J-Other | 250,000 | $0.00 | $25 | 1.40M | Form 4 ↗ |
RA CAPITAL MANAGEMENT, L.P. 10 percent owner | Apr 27, 2026 | J-Other | 250,000 | $0.00 | $25 | 932.6K | Form 4 ↗ |
RA CAPITAL MANAGEMENT, L.P. 10 percent owner | Feb 20, 2026 | Purchase | 74,751 | $7.27 | $543.4K | 1.18M | Form 4 ↗ |
RA CAPITAL MANAGEMENT, L.P. 10 percent owner | Feb 19, 2026 | Purchase | 74,268 | $7.21 | $535.5K | 1.11M | Form 4 ↗ |
RA CAPITAL MANAGEMENT, L.P. 10 percent owner | Feb 18, 2026 | Purchase | 74,577 | $7.04 | $525.0K | 1.03M | Form 4 ↗ |
ORBIMED ADVISORS LLC 10 percent owner | Apr 7, 2026 | Sale | 29,319 | $6.53 | $191.5K | 34.9K | Form 4 ↗ |
ORBIMED ADVISORS LLC 10 percent owner | Apr 7, 2026 | Sale | 2,400 | $6.38 | $15.3K | 32.5K | Form 4 ↗ |
ORBIMED ADVISORS LLC 10 percent owner | Apr 8, 2026 | Sale | 32,523 | $6.29 | $204.6K | 0 | Form 4 ↗ |
ORBIMED ADVISORS LLC 10 percent owner | Apr 8, 2026 | Sale | 40,416 | $6.52 | $263.5K | 0 | Form 4 ↗ |
Harvey Brian Nicholas Chief Financial Officer | Mar 25, 2026 | Award | 43,361 | $6.81 | $295.3K | 43.4K | Form 4 ↗ |
Source: /insider-trading/search (FMP stable). Buy/Sell direction: acquisitionOrDisposition A=Buy, D=Sell. RSU vesting (M-Exempt) excluded from sentiment bar. All data from SEC EDGAR public filings.
About institutional & insider ownership
Adicet Bio, Inc. (ACET) is primarily owned by institutional investors, who hold approximately 100.0% of total shares outstanding. Company insiders own approximately 11.92%, while retail and public investors account for the remaining 0.00%.
The largest institutional shareholder of Adicet Bio, Inc. is ORBIMED ADVISORS LLC, holding approximately 11.45 million shares — equal to 12.57% of outstanding shares — as of September 30, 2025.
A total of 54 institutional investors currently hold ACET stock, with a combined institutional value of approximately $41,645,212 as of the most recent 13F filing period.
Frequently asked questions
ACET ownershipAdicet Bio, Inc. (ACET) is primarily owned by institutional investors, who hold approximately 100.0% of shares. The largest shareholder is ORBIMED ADVISORS LLC with a 12.57% stake. Company insiders hold 11.92%. Data sourced from SEC Form 13F as of September 30, 2025.