Arcellx, Inc.
Arcellx, Inc. (ACLX) Stock Ownership
Institutional vs insider vs public ownership from 13F and float data — top holders, activity, and insider trades below.
SEC 13F · FMP · ACLX · as of Sep 30, 2025
Ownership Breakdown
220
Institutional Holders
▲ 8 vs Q2
$5.18B
Total Inst. Value
▲ $1.16B vs Q2
58.51M
Shares Outstanding
freeFloat 73.43%
63.07M
13F Shares Held
▲ 1.68M 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
ACLX largest shareholders · institutional ownership
Q3 2025 · SEC 13F
Showing top 10 holders
| Holder | Shares | % Owned | Weight | Value | Reported | Change |
|---|---|---|---|---|---|---|
GILEAD SCIENCES, INC. biological products, (no diagnostic substances) | 6.72M | 11.95% | 11.95% | $551.78B | Nov 13, 2025 | — held |
T. ROWE PRICE INVESTMENT MANAGEMENT, INC. biological products, (no diagnostic substances) | 6.35M | 11.30% | 11.30% | $521.53B | Nov 14, 2025 | ▲ 4.41M |
FMR LLC biological products, (no diagnostic substances) | 5.76M | 10.25% | 10.25% | $473.00B | Nov 13, 2025 | ▼ 210.8K |
PARADIGM BIOCAPITAL ADVISORS LP biological products, (no diagnostic substances) | 4.65M | 8.27% | 8.27% | $381.68B | Nov 14, 2025 | — held |
VANGUARD GROUP INC biological products, (no diagnostic substances) | 3.91M | 6.95% | 6.95% | $320.77B | Nov 7, 2025 | ▼ 37.8K |
BLACKROCK, INC. biological products, (no diagnostic substances) | 3.39M | 6.03% | 6.03% | $278.15B | Nov 12, 2025 | ▼ 80.3K |
NEA MANAGEMENT COMPANY, LLC biological products, (no diagnostic substances) | 3.05M | 5.42% | 5.42% | $250.02B | Nov 14, 2025 | ▼ 700.0K |
RA CAPITAL MANAGEMENT, L.P. biological products, (no diagnostic substances) | 3.04M | 5.40% | 5.40% | $249.30B | Nov 14, 2025 | — held |
PERCEPTIVE ADVISORS LLC biological products, (no diagnostic substances) | 2.47M | 4.39% | 4.39% | $202.65B | Nov 14, 2025 | ▼ 9.6K |
SR ONE CAPITAL MANAGEMENT, LP biological products, (no diagnostic substances) | 2.35M | 4.17% | 4.17% | $192.66B | Nov 12, 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
14
Increased
+5.96M shares2
New Positions
first time holders26
Decreased
−3.45M shares0
Sold Out
fully exitedNet shares change (top 50)
+2.51M
+5.96M / −3.45M
Net new holders
-10
2 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
ACLX insider trading · insider activity
Source: SEC Form 4
7
Buy transactions
55
Sell transactions
0.13
Buy/Sell ratio
$6M
Total disposed
Recent Insider Transactions
Showing 10 most recent · Common Stock only
| Name · Role | Date | Type | Shares | Price | Value | After Trans. | Filing |
|---|---|---|---|---|---|---|---|
Carroll Jill director | Apr 28, 2026 | U-Tender | 1,479,148 | $115.00 | $170.10M | 0 | Form 4 ↗ |
Carroll Jill director | Apr 28, 2026 | D-Return | 11,459 | $37.94 | $434.8K | 0 | Form 4 ↗ |
Carroll Jill director | Apr 28, 2026 | D-Return | 8,011 | $51.30 | $411.0K | 0 | Form 4 ↗ |
Carroll Jill director | Apr 28, 2026 | D-Return | 9,174 | $63.68 | $584.2K | 0 | Form 4 ↗ |
Behbahani Ali director | Apr 28, 2026 | U-Tender | 2,706 | $115.00 | $311.2K | 0 | Form 4 ↗ |
Behbahani Ali director | Apr 28, 2026 | D-Return | 11,459 | $37.94 | $434.8K | 0 | Form 4 ↗ |
Behbahani Ali director | Apr 28, 2026 | D-Return | 8,011 | $51.30 | $411.0K | 0 | Form 4 ↗ |
Behbahani Ali director | Apr 28, 2026 | D-Return | 9,174 | $63.68 | $584.2K | 0 | Form 4 ↗ |
Ware Olivia C director | Apr 28, 2026 | D-Return | 36,806 | $7.61 | $280.1K | 0 | Form 4 ↗ |
Ware Olivia C director | Apr 28, 2026 | D-Return | 11,459 | $37.94 | $434.8K | 0 | 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
Arcellx, Inc. (ACLX) is primarily owned by institutional investors, who hold approximately 100.0% of total shares outstanding. Company insiders own approximately 26.57%, while retail and public investors account for the remaining 0.00%.
The largest institutional shareholder of Arcellx, Inc. is GILEAD SCIENCES, INC., holding approximately 6.72 million shares — equal to 11.95% of outstanding shares — as of September 30, 2025.
A total of 220 institutional investors currently hold ACLX stock, with a combined institutional value of approximately $5.18 billion as of the most recent 13F filing period.
Frequently asked questions
ACLX ownershipArcellx, Inc. (ACLX) is primarily owned by institutional investors, who hold approximately 100.0% of shares. The largest shareholder is GILEAD SCIENCES, INC. with a 11.95% stake. Company insiders hold 26.57%. Data sourced from SEC Form 13F as of September 30, 2025.