IO Biotech, Inc.
IO Biotech, Inc. (IOBT) Stock Ownership
Institutional vs insider vs public ownership from 13F and float data — top holders, activity, and insider trades below.
SEC 13F · FMP · IOBT · as of Sep 30, 2025
Ownership Breakdown
21
Institutional Holders
▼ 5 vs Q2
$3.59M
Total Inst. Value
▼ $21.68M vs Q2
71.95M
Shares Outstanding
freeFloat 83.88%
9.90M
13F Shares Held
▼ 8.29M 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
IOBT largest shareholders · institutional ownership
Q3 2025 · SEC 13F
Showing top 10 holders
| Holder | Shares | % Owned | Weight | Value | Reported | Change |
|---|---|---|---|---|---|---|
NOVO HOLDINGS A/S pharmaceutical preparations | 2.51M | 3.81% | 3.81% | $912.27M | Nov 14, 2025 | ▼ 842.0K |
IKARIAN CAPITAL, LLC pharmaceutical preparations | 1.53M | 2.32% | 2.32% | $554.05M | Nov 14, 2025 | NEW |
MILLENNIUM MANAGEMENT LLC pharmaceutical preparations | 1.39M | 2.11% | 2.11% | $505.58M | Nov 14, 2025 | NEW |
MARSHALL WACE, LLP pharmaceutical preparations | 1.05M | 1.60% | 1.60% | $378.95M | Nov 13, 2025 | ▼ 1.05M |
BANK OF AMERICA CORP /DE/ pharmaceutical preparations | 800.0K | 1.21% | 1.21% | $290.38M | Feb 3, 2026 | ▼ 815.1K |
MORGAN STANLEY pharmaceutical preparations | 668.4K | 1.01% | 1.01% | $242.70M | May 27, 2026 | ▲ 14.7K |
BOOTHBAY FUND MANAGEMENT, LLC pharmaceutical preparations | 591.2K | 89.73% | 89.73% | $214.66M | Nov 14, 2025 | NEW |
RENAISSANCE TECHNOLOGIES LLC pharmaceutical preparations | 547.3K | 83.08% | 83.08% | $198.73M | Nov 13, 2025 | ▲ 408.0K |
POINT72 ASSET MANAGEMENT, L.P. pharmaceutical preparations | 250.0K | 37.95% | 37.95% | $90.78M | Nov 14, 2025 | NEW |
XTX TOPCO LTD pharmaceutical preparations | 179.2K | 27.20% | 27.20% | $65.07M | Nov 14, 2025 | ▲ 150.0K |
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
5
Increased
+575.2K shares9
New Positions
first time holders5
Decreased
−2.72M shares14
Sold Out
fully exitedNet shares change (top 50)
2.14M
+575.2K / −2.72M
Net new holders
-5
9 new / 14 exited
Based on top 50 institutional holders by position size. Fields: isNew, isSoldOut, changeInSharesNumber (FMP extract-analytics/holder, limit=50).
Insider Buying vs Selling
IOBT 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.
12
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 |
|---|---|---|---|---|---|---|---|
Smith David V director | Jun 5, 2025 | Award | 35,144 | $1.50 | $52.7K | 35.1K | Form 4 ↗ |
Hunter Heidi director | Jun 5, 2025 | Award | 35,144 | $1.50 | $52.7K | 35.1K | Form 4 ↗ |
Hirth Peter director | Jun 5, 2025 | Award | 35,144 | $1.50 | $52.7K | 35.1K | Form 4 ↗ |
Glaub Kathleen Sereda director | Jun 5, 2025 | Award | 35,144 | $1.50 | $52.7K | 35.1K | Form 4 ↗ |
Elling Christian E director | Jun 5, 2025 | Award | 35,144 | $1.50 | $52.7K | 35.1K | Form 4 ↗ |
Collins Helen Louise director | Jun 5, 2025 | Award | 35,144 | $1.50 | $52.7K | 35.1K | Form 4 ↗ |
Hunter Heidi director | May 30, 2025 | Purchase | 15,000 | $1.39 | $20.9K | 15.0K | Form 4 ↗ |
Zocca Mai-Britt Chief Executive Officer | Apr 2, 2025 | Award | 580,000 | $1.07 | $620.6K | 580.0K | Form 4 ↗ |
Sullivan Amy Chief Financial Officer | Apr 2, 2025 | Award | 215,000 | $1.07 | $230.1K | 215.0K | Form 4 ↗ |
Smith Devin Whittemore General Counsel | Apr 2, 2025 | Award | 140,000 | $1.07 | $149.8K | 140.0K | 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
IO Biotech, Inc. (IOBT) is primarily owned by institutional investors, who hold approximately 13.8% of total shares outstanding. Company insiders own approximately 16.12%, while retail and public investors account for the remaining 70.12%.
The largest institutional shareholder of IO Biotech, Inc. is NOVO HOLDINGS A/S, holding approximately 2.51 million shares — equal to 3.81% of outstanding shares — as of September 30, 2025.
A total of 21 institutional investors currently hold IOBT stock, with a combined institutional value of approximately $3,589,663 as of the most recent 13F filing period.
Frequently asked questions
IOBT ownershipIO Biotech, Inc. (IOBT) is primarily owned by institutional investors, who hold approximately 13.8% of shares. The largest shareholder is NOVO HOLDINGS A/S with a 3.81% stake. Company insiders hold 16.12%. Data sourced from SEC Form 13F as of September 30, 2025.