Prime Medicine, Inc.
Prime Medicine, Inc. (PRME) Stock Ownership
Institutional vs insider vs public ownership from 13F and float data — top holders, activity, and insider trades below.
SEC 13F · FMP · PRME · as of Sep 30, 2025
Ownership Breakdown
179
Institutional Holders
▲ 51 vs Q2
$511.62M
Total Inst. Value
▲ $366.48M vs Q2
180.62M
Shares Outstanding
freeFloat 32.76%
92.36M
13F Shares Held
▲ 33.62M 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
PRME largest shareholders · institutional ownership
Q3 2025 · SEC 13F
Showing top 10 holders
| Holder | Shares | % Owned | Weight | Value | Reported | Change |
|---|---|---|---|---|---|---|
ALPHABET INC. biological products, (no diagnostic substances) | 16.56M | 12.82% | 12.82% | $91.76B | Nov 7, 2025 | ▲ 1.50M |
T. ROWE PRICE INVESTMENT MANAGEMENT, INC. biological products, (no diagnostic substances) | 9.22M | 7.13% | 7.13% | $51.06B | Nov 14, 2025 | ▲ 2.73M |
BLACKROCK, INC. biological products, (no diagnostic substances) | 5.65M | 4.37% | 4.37% | $31.31B | Nov 12, 2025 | ▲ 1.17M |
ARK INVESTMENT MANAGEMENT LLC biological products, (no diagnostic substances) | 5.48M | 4.24% | 4.24% | $30.35B | Nov 12, 2025 | ▲ 3.16M |
VANGUARD GROUP INC biological products, (no diagnostic substances) | 4.92M | 3.81% | 3.81% | $27.27B | Nov 7, 2025 | ▲ 1.29M |
FARALLON CAPITAL MANAGEMENT LLC biological products, (no diagnostic substances) | 4.75M | 3.68% | 3.68% | $26.32B | Feb 17, 2026 | ▲ 4.00M |
SUMITOMO MITSUI TRUST HOLDINGS, INC. biological products, (no diagnostic substances) | 3.63M | 2.81% | 2.81% | $20.11B | Oct 27, 2025 | ▲ 2.04M |
NIKKO ASSET MANAGEMENT AMERICAS, INC. biological products, (no diagnostic substances) | 3.63M | 2.81% | 2.81% | $20.04B | Nov 12, 2025 | ▲ 2.04M |
CASDIN CAPITAL, LLC biological products, (no diagnostic substances) | 3.17M | 2.45% | 2.45% | $17.55B | Nov 14, 2025 | ▲ 1.60M |
WOODLINE PARTNERS LP biological products, (no diagnostic substances) | 3.00M | 2.32% | 2.32% | $16.63B | Nov 14, 2025 | NEW |
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
32
Increased
+26.88M shares10
New Positions
first time holders4
Decreased
−1.29M shares0
Sold Out
fully exitedNet shares change (top 50)
+25.59M
+26.88M / −1.29M
Net new holders
+38
10 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
PRME insider trading · insider activity
Source: SEC Form 4
1
Buy transactions
0
Sell transactions
0.00
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 |
|---|---|---|---|---|---|---|---|
Schenkein David P director | Jun 5, 2026 | Award | 75,000 | $3.06 | $229.5K | 75.0K | Form 4 ↗ |
Marrazzo Jeffrey D director | Jun 5, 2026 | Award | 75,000 | $3.06 | $229.5K | 75.0K | Form 4 ↗ |
NELSEN ROBERT
| Jun 5, 2026 | Award | 75,000 | $3.06 | $229.5K | 75.0K | Form 4 ↗ |
Kelly Michael Aaron director | Jun 5, 2026 | Award | 75,000 | $3.06 | $229.5K | 75.0K | Form 4 ↗ |
Foster-Cheek Kaye I director | Jun 5, 2026 | Award | 75,000 | $3.06 | $229.5K | 75.0K | Form 4 ↗ |
Chung Wendy director | Jun 5, 2026 | Award | 75,000 | $3.06 | $229.5K | 75.0K | Form 4 ↗ |
Cahill Thomas director | Jun 5, 2026 | Award | 75,000 | $3.06 | $229.5K | 75.0K | Form 4 ↗ |
Makhni Svetlana Ni Chief Financial Officer | Apr 16, 2026 | Award | 800,000 | $3.67 | $2.94M | 800.0K | Form 4 ↗ |
Reine Allan Chief Executive Officer | Feb 26, 2026 | Award | 1,300,000 | $4.38 | $5.69M | 1.30M | Form 4 ↗ |
LEE ANN L. Chief Technical Officer | Feb 23, 2026 | Award | 375,000 | $3.34 | $1.25M | 375.0K | 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
Prime Medicine, Inc. (PRME) is primarily owned by institutional investors, who hold approximately 51.1% of total shares outstanding. Company insiders own approximately 67.24%, while retail and public investors account for the remaining 0.00%.
The largest institutional shareholder of Prime Medicine, Inc. is ALPHABET INC., holding approximately 16.56 million shares — equal to 12.82% of outstanding shares — as of September 30, 2025.
A total of 179 institutional investors currently hold PRME stock, with a combined institutional value of approximately $511,622,160 as of the most recent 13F filing period.
Frequently asked questions
PRME ownershipPrime Medicine, Inc. (PRME) is primarily owned by institutional investors, who hold approximately 51.1% of shares. The largest shareholder is ALPHABET INC. with a 12.82% stake. Company insiders hold 67.24%. Data sourced from SEC Form 13F as of September 30, 2025.