Alkermes plc (ALKS) Ownership
ALKS ownership summary
as of October 18, 2026- Institutions
- 107.8% of shares outstanding
- Insiders
- 1.40% of shares outstanding
- Shares outstanding
- 167.8M
- Float
- 155.2M shares available to trade
- Short interest
- 14.72% 17.8M shares short
- Days to cover
- 8.24 short interest up 17.6% vs prior month
- Institutions 107.80%
- Insiders 1.40%
ALKS top institutional holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | BlackRock Inc | 17.43% | 29.2M | $1.21B | +921,329 (+3.3%) | June 30, 2026 |
| 2 | Baker Bros Advisors LP | 5.97% | 10.0M | $412.7M | — | June 30, 2026 |
| 3 | Vanguard Portfolio Management, LLC | 5.66% | 9.5M | $391.2M | −20,294 (−0.2%) | June 30, 2026 |
| 4 | State Street Corp | 5.46% | 9.2M | $377.6M | −304,711 (−3.2%) | June 30, 2026 |
| 5 | Vanguard Capital Management, LLC | 4.48% | 7.5M | $309.8M | +87,628 (+1.2%) | June 30, 2026 |
| 6 | T. Rowe Price Associates, Inc. | 4.02% | 6.7M | $277.7M | +2.1M (+44.4%) | June 30, 2026 |
| 7 | Renaissance Technologies Corp | 3.85% | 6.5M | $266.3M | +300,500 (+4.9%) | June 30, 2026 |
| 8 | Geode Capital Management, LLC | 2.67% | 4.5M | $184.6M | +295,609 (+7.1%) | June 30, 2026 |
| 9 | Dimensional Fund Advisors, Inc. | 2.50% | 4.2M | $172.9M | −327,505 (−7.2%) | June 30, 2026 |
| 10 | Deep Track Capital, LP | 2.38% | 4.0M | $164.9M | +409,677 (+11.4%) | June 30, 2026 |
| 11 | American Century Companies Inc | 2.36% | 4.0M | $163.0M | −2.1M (−34.9%) | June 30, 2026 |
| 12 | Holocene Advisors, LP | 2.15% | 3.6M | $148.5M | +1.3M (+55.4%) | June 30, 2026 |
| 13 | COMMODORE CAPITAL LP | 1.79% | 3.0M | $123.7M | −1.2M (−28.6%) | June 30, 2026 |
| 14 | Wellington Management Company LLP | 1.68% | 2.8M | $116.0M | −155,362 (−5.2%) | June 30, 2026 |
| 15 | PRIMECAP Management Company | 1.51% | 2.5M | $104.2M | −11,310 (−0.4%) | June 30, 2026 |
| 16 | First Trust Advisors L.P. | 1.44% | 2.4M | $99.8M | −547,769 (−18.5%) | June 30, 2026 |
| 17 | Charles Schwab Investment Management Inc | 1.39% | 2.3M | $96.3M | +98,361 (+4.4%) | June 30, 2026 |
| 18 | Nuveen, LLC | 1.39% | 2.3M | $95.8M | −136,372 (−5.5%) | June 30, 2026 |
| 19 | NORGES BANK | 1.29% | 2.2M | $88.9M | +211,080 (+10.8%) | June 30, 2026 |
| 20 | Bvf Inc | 1.28% | 2.2M | $88.8M | +154,704 (+7.7%) | June 30, 2026 |
Value at the latest close. Change = shares bought or sold in the latest quarterly filing (13F). In the top 20, 10 holders added 5.8M shares and 9 cut 4.8M.
ALKS top mutual fund and ETF holders
20 largest| # | Holder | % of shares | Shares | Value | Change | Reported |
|---|---|---|---|---|---|---|
| 1 | iShares Core S&P Small-Cap ETF | 5.96% | 10.0M | $411.9M | +2,124 (+0.0%) | September 30, 2026 |
| 2 | Vanguard MStar Total Stk Mkt Idx Invest | 3.16% | 5.3M | $218.8M | −6,230 (−0.1%) | August 31, 2026 |
| 3 | iShares Russell 2000 ETF | 2.59% | 4.3M | $178.9M | −50,048 (−1.1%) | September 30, 2026 |
| 4 | Vanguard Small Cap Index | 2.25% | 3.8M | $155.6M | −61,195 (−1.6%) | September 30, 2026 |
| 5 | State Street® SPDR® S&P® Biotech ETF | 1.95% | 3.3M | $135.0M | −62,350 (−1.9%) | September 30, 2026 |
| 6 | Vanguard MStar Small Cap Growth Indx Inv | 1.25% | 2.1M | $86.7M | −98,008 (−4.5%) | September 30, 2026 |
| 7 | Fidelity Small Cap Index | 1.09% | 1.8M | $75.5M | +15,154 (+0.8%) | July 31, 2026 |
| 8 | First Trust NYSE Arca Biotech ETF | 1.04% | 1.7M | $71.9M | — | September 30, 2026 |
| 9 | Vanguard Capital Opportunity Inv | 1.02% | 1.7M | $70.7M | −7,000 (−0.4%) | June 30, 2026 |
| 10 | iShares S&P Small-Cap 600 Growth ETF | 0.93% | 1.6M | $64.0M | — | September 30, 2026 |
| 11 | State Street SPDR Port S&P 600 Sm CpETF | 0.91% | 1.5M | $63.0M | — | September 30, 2026 |
| 12 | iShares Biotechnology ETF | 0.76% | 1.3M | $52.3M | −9,624 (−0.8%) | September 30, 2026 |
| 13 | iShares Russell 2000 Growth ETF | 0.75% | 1.3M | $51.6M | −1,585 (−0.1%) | September 30, 2026 |
| 14 | Vanguard Tax-Managed Small Cap Adm | 0.64% | 1.1M | $43.9M | −9,850 (−0.9%) | September 30, 2026 |
| 15 | Invesco S&P SmallCap Momentum ETF | 0.61% | 1.0M | $42.3M | — | September 30, 2026 |
| 16 | American Century Small Cap Growth Inv | 0.59% | 993K | $40.9M | — | September 30, 2026 |
| 17 | Vanguard Russell 2000 ETF | 0.58% | 975K | $40.2M | +10,894 (+1.1%) | September 30, 2026 |
| 18 | State Street® SPDR® S&P 600™ Sm Cp GrETF | 0.57% | 960K | $39.6M | — | September 30, 2026 |
| 19 | T. Rowe Price New Horizons | 0.53% | 888K | $36.6M | +88,849 (+11.1%) | September 30, 2026 |
| 20 | Schwab US Small-Cap ETF™ | 0.53% | 883K | $36.4M | +594 (+0.1%) | September 30, 2026 |
Funds report holdings monthly or quarterly; dates differ by fund.
ALKS insider transactions
latest 16| Date | Name | Transaction | Price | Shares | Value |
|---|---|---|---|---|---|
| 2026-04-06 | David Joseph Gaffin | Sell | $34.57 | 2,034 | $70,315 |
| 2026-04-01 | Craig C Hopkinson | Sell | $35.51 | 9,000 | $319,590 |
| 2026-03-02 | Christian Todd Nichols | Sell | $30.00 | 6,000 | $180,000 |
| 2026-03-02 | Craig C Hopkinson | Sell | $29.72 | 9,000 | $267,480 |
| 2026-03-02 | David Joseph Gaffin | Sell | $29.29 | 2,034 | $59,576 |
| 2026-02-02 | Craig C Hopkinson | Sell | $33.93 | 9,000 | $305,370 |
| 2026-02-02 | Shane Cooke | Sell | $34.57 | 61,200 | $2.1M |
| 2026-02-02 | Shane Cooke | Sell | $34.57 | 61,200 | $2.1M |
| 2026-01-08 | Craig C Hopkinson | Sell | $30.00 | 5,000 | $150,000 |
| 2026-01-02 | Craig C Hopkinson | Sell | $28.00 | 4,000 | $112,000 |
| 2025-12-03 | Craig C Hopkinson | Sell | $30.00 | 3,748 | $112,440 |
| 2025-12-01 | Craig C Hopkinson | Sell | $29.30 | 4,000 | $117,200 |
| 2025-11-03 | Craig C Hopkinson | Sell | $30.38 | 9,000 | $273,420 |
| 2025-10-15 | Craig C Hopkinson | Sell | $31.53 | 9,000 | $283,770 |
| 2025-06-10 | Christian Todd Nichols | Sell | $31.09 | 3,334 | $103,654 |
| 2025-06-09 | Christian Todd Nichols | Sell | $31.95 | 3,333 | $106,489 |
Reported trades by company officers, directors and other filers (including disclosures by members of Congress where EODHD lists them). "—" where the filing gives no share count.
ALKS shares outstanding
Year-end shares outstanding, adjusted for splits.
Who owns ALKS
Institutional investors own 107.8% of Alkermes's shares and insiders 1.40%. The largest holder is BlackRock Inc with 17.43% of the shares (29.2M), as of June 30, 2026. Among the top 20 institutions, 10 added shares and 9 reduced their stake in the latest filings. Short interest is 14.72% of the float, or 8.24 days of average trading volume. The share count rose 8.5% since 2014.
Related: ALKS analyst forecast, ALKS key metrics. See the ALKS stock overview for the latest quote and news.
ALKS ownership FAQ
Who owns the most Alkermes stock?
The largest shareholders of Alkermes are BlackRock Inc (17.43%), Baker Bros Advisors LP (5.97%), Vanguard Portfolio Management, LLC (5.66%), State Street Corp (5.46%), Vanguard Capital Management, LLC (4.48%).
What percentage of Alkermes is owned by institutions?
Institutions hold 107.8% of Alkermes's shares outstanding; insiders hold 1.40%.
Which funds own Alkermes?
The largest fund holders of Alkermes are iShares Core S&P Small-Cap ETF (5.96%), Vanguard MStar Total Stk Mkt Idx Invest (3.16%), iShares Russell 2000 ETF (2.59%), Vanguard Small Cap Index (2.25%), State Street® SPDR® S&P® Biotech ETF (1.95%).
What is Alkermes's short interest?
17.8M shares of Alkermes were sold short, 14.72% of the float; at the average daily volume it would take 8.24 days to cover.
Are insiders buying or selling Alkermes?
Of the latest 16 reported insider transactions in Alkermes (since June 9, 2025), 0 were purchases and 16 were sales.
How many shares of Alkermes are outstanding?
Alkermes has 167.8M shares outstanding, of which 155.2M are in the public float.