Achilles Therapeutics plc
Achilles Therapeutics plc (ACHL) Stock Ownership
Institutional vs insider vs public ownership from 13F and float data — top holders, activity, and insider trades below.
SEC 13F · FMP · ACHL · as of Sep 30, 2025
Ownership Breakdown
2
Institutional Holders
$7,822
Total Inst. Value
41.10M
Shares Outstanding
freeFloat 48.80%
5,286
13F Shares Held
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
ACHL largest shareholders · institutional ownership
Q3 2025 · SEC 13F
Showing top 2 holders
| Holder | Shares | % Owned | Weight | Value | Reported | Change |
|---|---|---|---|---|---|---|
RHUMBLINE ADVISERS biological products, (no diagnostic substances) | 4.5K | 1.11% | 1.11% | $6.63M | Nov 6, 2025 | — held |
GAMMA INVESTING LLC biological products, (no diagnostic substances) | 806 | 0.20% | 0.20% | $1.19M | Oct 2, 2025 | — held |
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
0
Increased
+0 shares0
New Positions
first time holders0
Decreased
−0 shares0
Sold Out
fully exitedNet shares change (top 50)
+0
+0 / −0
Net new holders
+0
0 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
ACHL insider trading · insider activity
Source: SEC Form 4
Recent Insider Transactions
Showing 10 most recent · Common Stock only
No recent insider transactions reported.
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
Achilles Therapeutics plc (ACHL) is primarily owned by institutional investors, who hold approximately 0.0% of total shares outstanding. Company insiders own approximately 51.20%, while retail and public investors account for the remaining 48.79%.
The largest institutional shareholder of Achilles Therapeutics plc is RHUMBLINE ADVISERS, holding approximately 4,480 shares — equal to 1.11% of outstanding shares — as of September 30, 2025.
A total of 2 institutional investors currently hold ACHL stock, with a combined institutional value of approximately $7,822 as of the most recent 13F filing period.
Frequently asked questions
ACHL ownershipAchilles Therapeutics plc (ACHL) is primarily owned by institutional investors, who hold approximately 0.0% of shares. The largest shareholder is RHUMBLINE ADVISERS with a 1.11% stake. Company insiders hold 51.20%. Data sourced from SEC Form 13F as of September 30, 2025.