OS Therapies Incorporated
OS Therapies Incorporated (OSTX) Stock Ownership
Institutional vs insider vs public ownership from 13F and float data — top holders, activity, and insider trades below.
SEC 13F · FMP · OSTX · as of Sep 30, 2025
Ownership Breakdown
25
Institutional Holders
▲ 12 vs Q2
$3.07M
Total Inst. Value
▲ $1.93M vs Q2
44.54M
Shares Outstanding
freeFloat 57.03%
1.56M
13F Shares Held
▲ 959,494 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
OSTX largest shareholders · institutional ownership
Q3 2025 · SEC 13F
Showing top 10 holders
| Holder | Shares | % Owned | Weight | Value | Reported | Change |
|---|---|---|---|---|---|---|
CM MANAGEMENT, LLC pharmaceutical preparations | 400.0K | 1.25% | 1.25% | $784.00M | Nov 13, 2025 | ▲ 25.0K |
MARSHALL WACE, LLP pharmaceutical preparations | 198.6K | 62.13% | 62.13% | $389.16M | Nov 13, 2025 | NEW |
VANGUARD GROUP INC pharmaceutical preparations | 188.3K | 58.91% | 58.91% | $369.00M | Nov 7, 2025 | NEW |
GEODE CAPITAL MANAGEMENT, LLC pharmaceutical preparations | 187.7K | 58.73% | 58.73% | $367.87M | Nov 12, 2025 | NEW |
MILLENNIUM MANAGEMENT LLC pharmaceutical preparations | 93.6K | 29.28% | 29.28% | $183.41M | Nov 14, 2025 | NEW |
TWO SIGMA INVESTMENTS, LP pharmaceutical preparations | 86.2K | 26.99% | 26.99% | $169.04M | Nov 14, 2025 | NEW |
VIRTU FINANCIAL LLC pharmaceutical preparations | 75.8K | 23.72% | 23.72% | $149.00M | Nov 14, 2025 | ▲ 54.3K |
NORTHERN TRUST CORP pharmaceutical preparations | 56.3K | 17.61% | 17.61% | $110.28M | Nov 14, 2025 | NEW |
STATE STREET CORP pharmaceutical preparations | 50.3K | 15.74% | 15.74% | $98.59M | Nov 14, 2025 | NEW |
BLACKROCK, INC. pharmaceutical preparations | 48.2K | 15.07% | 15.07% | $94.40M | Nov 12, 2025 | ▲ 17.9K |
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
5
Increased
+99.0K shares13
New Positions
first time holders2
Decreased
−52.9K shares1
Sold Out
fully exitedNet shares change (top 50)
+46.1K
+99.0K / −52.9K
Net new holders
+15
13 new / 1 exited
Based on top 50 institutional holders by position size. Fields: isNew, isSoldOut, changeInSharesNumber (FMP extract-analytics/holder, limit=50).
Insider Buying vs Selling
OSTX insider trading · insider activity
Source: SEC Form 4
Insiders have been primarily selling shares recently. Selling may be driven by pre-scheduled Rule 10b5-1 plans rather than negative sentiment.
0
Buy transactions
3
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 |
|---|---|---|---|---|---|---|---|
Romness Paul A. President and CEO | Dec 5, 2024 | Award | 500,000 | $1.86 | $930.0K | 500.0K | Form 4 ↗ |
McKean-Dieser Avril Suzette director | Jan 22, 2026 | Award | 50,000 | $1.34 | $67.0K | 50.0K | Form 4 ↗ |
Search Theodore F. director | Jan 22, 2026 | Award | 50,000 | $1.34 | $67.0K | 50.0K | Form 4 ↗ |
Ciccio John director | Jan 22, 2026 | Award | 50,000 | $1.34 | $67.0K | 50.0K | Form 4 ↗ |
Acevedo Christopher P. Chief Financial Officer | Jan 22, 2026 | Award | 100,000 | $1.34 | $134.0K | 100.0K | Form 4 ↗ |
PETIT ROBERT See Remarks | Jan 22, 2026 | Award | 100,000 | $1.34 | $134.0K | 100.0K | Form 4 ↗ |
Romness Paul A. President and CEO | Jan 22, 2026 | Award | 1,000,000 | $1.34 | $1.34M | 1.00M | Form 4 ↗ |
Jarry Olivier Roger director | Jan 22, 2026 | Award | 50,000 | $1.34 | $67.0K | 50.0K | Form 4 ↗ |
Galzahr Karim director | Jan 22, 2026 | Award | 50,000 | $1.34 | $67.0K | 50.0K | Form 4 ↗ |
Romness Paul A. President and CEO | Oct 21, 2025 | Award | 1,000,000 | $1.80 | $1.80M | 1.00M | 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
OS Therapies Incorporated (OSTX) is primarily owned by institutional investors, who hold approximately 3.5% of total shares outstanding. Company insiders own approximately 42.97%, while retail and public investors account for the remaining 53.52%.
The largest institutional shareholder of OS Therapies Incorporated is CM MANAGEMENT, LLC, holding approximately 400,000 shares — equal to 1.25% of outstanding shares — as of September 30, 2025.
A total of 25 institutional investors currently hold OSTX stock, with a combined institutional value of approximately $3,065,164 as of the most recent 13F filing period.
Frequently asked questions
OSTX ownershipOS Therapies Incorporated (OSTX) is primarily owned by institutional investors, who hold approximately 3.5% of shares. The largest shareholder is CM MANAGEMENT, LLC with a 1.25% stake. Company insiders hold 42.97%. Data sourced from SEC Form 13F as of September 30, 2025.