Korro Bio, Inc.
Korro Bio, Inc. (KRRO) Stock Ownership
Institutional vs insider vs public ownership from 13F and float data — top holders, activity, and insider trades below.
SEC 13F · FMP · KRRO · as of Sep 30, 2025
Ownership Breakdown
91
Institutional Holders
▲ 21 vs Q2
$465.52M
Total Inst. Value
▲ $350.72M vs Q2
9.95M
Shares Outstanding
freeFloat 56.44%
9.72M
13F Shares Held
▲ 669,037 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
KRRO largest shareholders · institutional ownership
Q3 2025 · SEC 13F
Showing top 10 holders
| Holder | Shares | % Owned | Weight | Value | Reported | Change |
|---|---|---|---|---|---|---|
ATLAS VENTURE LIFE SCIENCE ADVISORS, LLC pharmaceutical preparations | 1.14M | 12.11% | 12.11% | $54.46B | Nov 13, 2025 | — held |
NEA MANAGEMENT COMPANY, LLC pharmaceutical preparations | 1.09M | 11.62% | 11.62% | $52.24B | Nov 14, 2025 | — held |
DRIEHAUS CAPITAL MANAGEMENT LLC pharmaceutical preparations | 672.0K | 7.16% | 7.16% | $32.18B | Nov 14, 2025 | ▲ 91.1K |
FMR LLC pharmaceutical preparations | 563.7K | 6.00% | 6.00% | $26.99B | Nov 13, 2025 | ▼ 75.5K |
POINT72 ASSET MANAGEMENT, L.P. pharmaceutical preparations | 532.0K | 5.66% | 5.66% | $25.48B | Nov 14, 2025 | ▼ 8.1K |
CORMORANT ASSET MANAGEMENT, LP pharmaceutical preparations | 465.0K | 4.95% | 4.95% | $22.27B | Nov 14, 2025 | — held |
BLACKROCK, INC. pharmaceutical preparations | 446.7K | 4.76% | 4.76% | $21.39B | Nov 12, 2025 | ▼ 15.2K |
SIREN, L.L.C. pharmaceutical preparations | 418.8K | 4.46% | 4.46% | $20.06B | Nov 13, 2025 | — held |
TCG CROSSOVER MANAGEMENT, LLC pharmaceutical preparations | 416.3K | 4.43% | 4.43% | $19.94B | Nov 17, 2025 | NEW |
VANGUARD GROUP INC pharmaceutical preparations | 395.7K | 4.21% | 4.21% | $18.95B | Nov 7, 2025 | ▲ 8.9K |
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
21
Increased
+898.7K shares10
New Positions
first time holders10
Decreased
−376.6K shares0
Sold Out
fully exitedNet shares change (top 50)
+522.0K
+898.7K / −376.6K
Net new holders
+21
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
KRRO 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
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 |
|---|---|---|---|---|---|---|---|
Aiyar Ram President and CEO | May 29, 2026 | Sale | 15,152 | $12.98 | $196.7K | 74.8K | Form 4 ↗ |
FORMELA JEAN FRANCOIS director | May 28, 2026 | Sale | 2,441 | $13.95 | $34.1K | 939.6K | Form 4 ↗ |
FORMELA JEAN FRANCOIS director | May 28, 2026 | Sale | 419 | $13.95 | $5.8K | 194.7K | Form 4 ↗ |
Aiyar Ram President and CEO | May 26, 2026 | Award | 50,000 | $12.33 | $616.5K | 90.0K | Form 4 ↗ |
Lynx1 Capital Management LP 10 percent owner | Mar 31, 2026 | Purchase | 520 | $10.60 | $5.5K | 1.54M | Form 4 ↗ |
Yang Rick 10 percent owner | Mar 10, 2026 | Purchase | 207,100 | $11.11 | $2.30M | 1.30M | Form 4 ↗ |
Yang Rick 10 percent owner | Mar 10, 2026 | Purchase | 242,945 | $0.00 | $242.945 | 242.9K | Form 4 ↗ |
SANDELL SCOTT D 10 percent owner | Mar 10, 2026 | Purchase | 207,100 | $11.11 | $2.30M | 1.30M | Form 4 ↗ |
SANDELL SCOTT D 10 percent owner | Mar 10, 2026 | Purchase | 242,945 | $0.00 | $242.945 | 242.9K | Form 4 ↗ |
New Enterprise Associates 17, L.P. 10 percent owner | Mar 10, 2026 | Purchase | 207,100 | $11.11 | $2.30M | 1.30M | 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
Korro Bio, Inc. (KRRO) is primarily owned by institutional investors, who hold approximately 97.7% of total shares outstanding. Company insiders own approximately 43.56%, while retail and public investors account for the remaining 0.00%.
The largest institutional shareholder of Korro Bio, Inc. is ATLAS VENTURE LIFE SCIENCE ADVISORS, LLC, holding approximately 1.14 million shares — equal to 12.11% of outstanding shares — as of September 30, 2025.
A total of 91 institutional investors currently hold KRRO stock, with a combined institutional value of approximately $465,518,160 as of the most recent 13F filing period.
Frequently asked questions
KRRO ownershipKorro Bio, Inc. (KRRO) is primarily owned by institutional investors, who hold approximately 97.7% of shares. The largest shareholder is ATLAS VENTURE LIFE SCIENCE ADVISORS, LLC with a 12.11% stake. Company insiders hold 43.56%. Data sourced from SEC Form 13F as of September 30, 2025.