Alkermes plc
Alkermes plc (ALKS) Stock Ownership
Institutional vs insider vs public ownership from 13F and float data — top holders, activity, and insider trades below.
SEC 13F · FMP · ALKS · as of Mar 31, 2025
Ownership Breakdown
384
Institutional Holders
▲ 30 vs Q4
$5.69B
Total Inst. Value
▲ $876.70M vs Q4
166.68M
Shares Outstanding
freeFloat 92.44%
172.37M
13F Shares Held
▲ 4.94M vs Q4
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
ALKS largest shareholders · institutional ownership
Q1 2025 · SEC 13F
Showing top 10 holders
| Holder | Shares | % Owned | Weight | Value | Reported | Change |
|---|---|---|---|---|---|---|
BLACKROCK, INC. pharmaceutical preparations | 27.41M | 16.77% | 16.77% | $904.96B | May 2, 2025 | ▼ 446.5K |
VANGUARD GROUP INC pharmaceutical preparations | 18.21M | 11.15% | 11.15% | $601.38B | May 9, 2025 | ▼ 283.5K |
PRICE T ROWE ASSOCIATES INC /MD/ pharmaceutical preparations | 11.79M | 7.21% | 7.21% | $389.25B | May 14, 2025 | ▼ 468.2K |
STATE STREET CORP pharmaceutical preparations | 8.02M | 4.91% | 4.91% | $264.91B | May 15, 2025 | ▼ 792.3K |
RTW INVESTMENTS, LP pharmaceutical preparations | 6.88M | 4.21% | 4.21% | $227.33B | May 15, 2025 | ▼ 673.1K |
RENAISSANCE TECHNOLOGIES LLC pharmaceutical preparations | 5.74M | 3.51% | 3.51% | $189.50B | May 14, 2025 | ▲ 260.1K |
JPMORGAN CHASE & CO pharmaceutical preparations | 5.23M | 3.20% | 3.20% | $172.86B | May 12, 2025 | ▲ 4.35M |
BAKER BROS. ADVISORS LP pharmaceutical preparations | 4.48M | 2.74% | 2.74% | $148.04B | May 15, 2025 | ▲ 301.5K |
GEODE CAPITAL MANAGEMENT, LLC pharmaceutical preparations | 3.94M | 2.41% | 2.41% | $130.12B | May 13, 2025 | ▲ 121.0K |
AMERICAN CENTURY COMPANIES INC pharmaceutical preparations | 3.47M | 2.12% | 2.12% | $114.44B | May 13, 2025 | ▲ 15.0K |
Data from SEC Form 13F filings. Ownership bar normalised to largest holder. Change flags: isNew / isSoldOut / changeInSharesNumber (FMP extract-analytics/holder).
Institutional Activity
Q1 2025 vs prior quarter
Q1 2025
23
Increased
+15.69M shares4
New Positions
first time holders21
Decreased
−10.99M shares0
Sold Out
fully exitedNet shares change (top 50)
+4.69M
+15.69M / −10.99M
Net new holders
+6
4 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
ALKS 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.
30
Buy transactions
30
Sell transactions
1.00
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 |
|---|---|---|---|---|---|---|---|
Gaffin David Joseph EVP, CLO, Alkermes, Inc. | Jun 4, 2026 | Sale | 2,034 | $43.05 | $87.6K | 229.5K | Form 4 ↗ |
Hopkinson Craig C. EVP R&D, Chief Medical Officer | Jun 1, 2026 | Sale | 9,000 | $41.67 | $375.0K | 77.4K | Form 4 ↗ |
Parisi Samuel Joseph VP, Finance (Interim PAO) | May 29, 2026 | Sale | 16,217 | $42.36 | $687.0K | 7.7K | Form 4 ↗ |
Wright Christopher I director | May 21, 2026 | Tax Withhold | 1,475 | $36.95 | $54.5K | 27.7K | Form 4 ↗ |
Wright Christopher I director | May 20, 2026 | Award | 11,538 | $36.98 | $426.7K | 11.5K | Form 4 ↗ |
Wright Christopher I director | May 20, 2026 | Award | 5,409 | — | — | 5.4K | Form 4 ↗ |
Wilson Frank Anders director | May 21, 2026 | Tax Withhold | 1,475 | $36.95 | $54.5K | 35.8K | Form 4 ↗ |
Wilson Frank Anders director | May 20, 2026 | Award | 11,538 | $36.98 | $426.7K | 11.5K | Form 4 ↗ |
Wilson Frank Anders director | May 20, 2026 | Award | 5,409 | — | — | 5.4K | 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
Alkermes plc (ALKS) is primarily owned by institutional investors, who hold approximately 100.0% of total shares outstanding. Company insiders own approximately 7.56%, while retail and public investors account for the remaining 0.00%.
The largest institutional shareholder of Alkermes plc is BLACKROCK, INC., holding approximately 27.41 million shares — equal to 16.77% of outstanding shares — as of March 31, 2025.
A total of 384 institutional investors currently hold ALKS stock, with a combined institutional value of approximately $5.69 billion as of the most recent 13F filing period.
Frequently asked questions
ALKS ownershipAlkermes plc (ALKS) is primarily owned by institutional investors, who hold approximately 100.0% of shares. The largest shareholder is BLACKROCK, INC. with a 16.77% stake. Company insiders hold 7.56%. Data sourced from SEC Form 13F as of March 31, 2025.