System1, Inc.
System1, Inc. (SST) Stock Ownership
Institutional vs insider vs public ownership from 13F and float data — top holders, activity, and insider trades below.
SEC 13F · FMP · SST · as of Sep 30, 2025
Ownership Breakdown
30
Institutional Holders
▼ 5 vs Q2
$22.52M
Total Inst. Value
▲ $4.59M vs Q2
9.94M
Shares Outstanding
freeFloat 22.03%
3.20M
13F Shares Held
▼ 43,840 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
SST largest shareholders · institutional ownership
Q3 2025 · SEC 13F
Showing top 10 holders
| Holder | Shares | % Owned | Weight | Value | Reported | Change |
|---|---|---|---|---|---|---|
CANNAE HOLDINGS, INC. services-computer programming, data processing, etc. | 2.70M | 34.54% | 34.54% | $19.02B | Nov 5, 2025 | — held |
BANK OF AMERICA CORP /DE/ services-computer programming, data processing, etc. | 161.6K | 2.07% | 2.07% | $1.14B | Feb 3, 2026 | ▼ 12.7K |
CERITY PARTNERS LLC services-computer programming, data processing, etc. | 116.9K | 1.49% | 1.49% | $822.74M | Oct 22, 2025 | ▲ 7.6K |
VANGUARD GROUP INC services-computer programming, data processing, etc. | 46.9K | 60.02% | 60.02% | $330.41M | Nov 7, 2025 | ▼ 373 |
MILLENNIUM MANAGEMENT LLC services-computer programming, data processing, etc. | 38.6K | 49.31% | 49.31% | $271.47M | Nov 14, 2025 | ▼ 4.2K |
MARSHALL WACE, LLP services-computer programming, data processing, etc. | 36.3K | 46.38% | 46.38% | $255.35M | Nov 13, 2025 | NEW |
BLACKROCK, INC. services-computer programming, data processing, etc. | 24.2K | 30.96% | 30.96% | $170.44M | Nov 12, 2025 | ▼ 14.9K |
RENAISSANCE TECHNOLOGIES LLC services-computer programming, data processing, etc. | 17.1K | 21.89% | 21.89% | $120.53M | Nov 13, 2025 | ▲ 5.1K |
GEODE CAPITAL MANAGEMENT, LLC services-computer programming, data processing, etc. | 14.4K | 18.39% | 18.39% | $101.29M | Nov 12, 2025 | ▼ 7.1K |
XTX TOPCO LTD services-computer programming, data processing, etc. | 12.5K | 15.99% | 15.99% | $88.03M | 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
5
Increased
+13.9K shares3
New Positions
first time holders14
Decreased
−57.8K shares8
Sold Out
fully exitedNet shares change (top 50)
44.0K
+13.9K / −57.8K
Net new holders
-14
3 new / 8 exited
Based on top 50 institutional holders by position size. Fields: isNew, isSoldOut, changeInSharesNumber (FMP extract-analytics/holder, limit=50).
Insider Buying vs Selling
SST 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
4
Sell transactions
0.25
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 |
|---|---|---|---|---|---|---|---|
Kidambi Tridivesh Chief Financial Officer | May 29, 2026 | Award | 35,300 | — | — | 181.8K | Form 4 ↗ |
Kidambi Tridivesh Chief Financial Officer | Apr 15, 2026 | Purchase | 26,910 | $3.00 | $80.7K | 146.8K | Form 4 ↗ |
Kidambi Tridivesh Chief Financial Officer | Apr 15, 2026 | Tax Withhold | 301 | $2.26 | $680.26 | 146.5K | Form 4 ↗ |
Sestanovich Elizabeth Chief People Officer | Apr 15, 2026 | Tax Withhold | 341 | $2.26 | $770.66 | 58.9K | Form 4 ↗ |
Coppola Brian Chief Ad Operations Officer | Apr 15, 2026 | Tax Withhold | 331 | $2.26 | $748.06 | 65.9K | Form 4 ↗ |
Weinrot Daniel J General Counsel & Secretary | Apr 15, 2026 | Tax Withhold | 341 | $2.26 | $770.66 | 69.1K | Form 4 ↗ |
Kidambi Tridivesh Chief Financial Officer | Jan 28, 2026 | Tax Withhold | 258 | $4.18 | $1.1K | 119.9K | Form 4 ↗ |
Sestanovich Elizabeth Chief People Officer | Jan 28, 2026 | Tax Withhold | 211 | $4.18 | $881.98 | 59.3K | Form 4 ↗ |
Coppola Brian Chief Ad Operations Officer | Jan 28, 2026 | Tax Withhold | 231 | $4.18 | $965.58 | 66.2K | Form 4 ↗ |
Weinrot Daniel J General Counsel & Secretary | Jan 28, 2026 | Tax Withhold | 211 | $4.18 | $881.98 | 69.4K | 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
System1, Inc. (SST) is primarily owned by institutional investors, who hold approximately 32.2% of total shares outstanding. Company insiders own approximately 77.97%, while retail and public investors account for the remaining 0.00%.
The largest institutional shareholder of System1, Inc. is CANNAE HOLDINGS, INC., holding approximately 2.70 million shares — equal to 34.54% of outstanding shares — as of September 30, 2025.
A total of 30 institutional investors currently hold SST stock, with a combined institutional value of approximately $22,516,874 as of the most recent 13F filing period.
Frequently asked questions
SST ownershipSystem1, Inc. (SST) is primarily owned by institutional investors, who hold approximately 32.2% of shares. The largest shareholder is CANNAE HOLDINGS, INC. with a 34.54% stake. Company insiders hold 77.97%. Data sourced from SEC Form 13F as of September 30, 2025.