Alkermes plc
US ˙ NasdaqGS ˙ IE00B56GVS15

SecurityALKS / Alkermes plc
InstitutionMarshall Wace, Llp
Latest Disclosed Ownership999,322 shares
Latest Disclosed Value $ 35,336,026
Marshall Wace, Llp reports 669.31% increase in ownership of ALKS / Alkermes plc

On May 14, 2026 - Marshall Wace, Llp filed a 13F-HR form disclosing ownership of 999,322 shares of Alkermes plc (US:ALKS) valued at $35,336,026 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 129,899 shares of Alkermes plc. This represents a change in shares of 669.31% during the quarter. The current value of the position is $42,770,982 USD.

Institutional Ownership: 13F and NPORT Filings

The Security and Class in the table below are shown exactly as filed by the investor. We do our best to track continuity of investments through acquisitions, and this will be reflected in the table as changes in names. In addition to descriptive data, performance of the investment is shown over time. To calculate quarterly performance, we first calculate cost basis of the shares purchased during the quarter, then use that to calculate gross profit. Quarterly return is Gross Profit / Starting Portfolio value.

Note that cost basis is calculated and stored in thousands, so small quarterly changes in shares frequently result in a cost basis of zero.

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Disclosed Equity Positions (from 13F/NPORT Filings)
File
Date		 Effective
Date		Form Security Class ID Avg Price
Paid (Est)		 Reported
Shares		 ΔShares ΔShares
(%)		 Reported
Value
(x1000)		 ΔValue
(%)		 Alloc
(%)		 ΔAlloc ΔAlloc (%) Cost Basis
(x1000)		 Unrealized
Gain/Loss
(x1000)
2026-05-14 2026-03-31 13F ALKERMES COMMON STOCK G01767105 999,322 869,423 669.31 35,336 872.37 0.0167
2026-02-13 2025-12-31 13F ALKERMES COMMON STOCK G01767105 129,899 129,899 3,635 0.0033
2025-11-13 2025-09-30 13F ALKERMES COMMON STOCK G01767105 0 -207,511 -100.00 0 -100.00
2025-08-13 2025-06-30 13F ALKERMES COMMON STOCK G01767105 207,511 207,511 5,937 0.0067
2024-02-14 2023-12-31 13F ALKERMES COMMON STOCK G01767105 0 -1,768,014 -100.00 0 -100.00
2023-11-14 2023-09-30 13F ALKERMES COMMON STOCK G01767105 1,768,014 1,042,937 143.84 49,522 118.22 0.1003
2023-08-14 2023-06-30 13F ALKERMES COMMON STOCK G01767105 725,077 611,673 539.38 22,695 610.08 0.0443
2023-05-15 2023-03-31 13F ALKERMES COMMON STOCK G01767105 113,404 0 0.00 3,197 7.86 0.0068
2023-02-14 2022-12-31 13F ALKERMES COMMON STOCK G01767105 113,404 113,404 2,963 0.0067
2022-02-14 2021-12-31 13F ALKERMES COMMON STOCK G01767105 0 -21,043 -100.00 0 -100.00
2021-11-15 2021-09-30 13F ALKERMES COMMON STOCK G01767105 21,043 21,043 649 0.0027
2021-05-17 2021-03-31 13F ALKERMES COMMON STOCK G01767105 0 -47,891 -100.00 0 -100.00
2021-02-16 2020-12-31 13F ALKERMES COMMON STOCK G01767105 47,891 47,891 955 0.0052
2020-08-13 2020-06-30 13F ALKERMES COMMON STOCK G01767105 0 -19,063 -100.00 0 -100.00
2020-05-15 2020-03-31 13F ALKERMES COMMON STOCK G01767105 19,063 -211,383 -91.73 275 -94.15 0.0027
2020-02-14 2019-12-31 13F ALKERMES COMMON STOCK G01767105 230,446 171,730 292.48 4,700 310.48 0.0323
2019-11-14 2019-09-30 13F ALKERMES COMMON STOCK G01767105 58,716 58,716 1,145 0.0090
2019-08-14 2019-06-30 13F ALKERMES COMMON STOCK G01767105 0 -1,283 -100.00 0 -100.00
2019-05-29 2019-03-31 13F/A-1 ALKERMES COMMON STOCK G01767105 1,283 0 0.00 47 23.68 0.0004
2019-05-14 2019-03-31 13F ALKERMES COMMON STOCK G01767105 1,283 0 47
2019-02-14 2018-12-31 13F ALKERMES COMMON STOCK G01767105 1,283 1,283 38 0.0004
2017-05-12 2017-03-31 13F ALKERMES COMMON STOCK G01767105 0 -639,670 -100.00 0 -100.00
2017-02-10 2016-12-31 13F ALKERMES COMMON STOCK G01767105 639,670 320,697 100.54 35,553 137.00 0.2338
2016-11-10 2016-09-30 13F ALKERMES COMMON STOCK G01767105 318,973 -135,517 -29.82 15,001 -23.63 0.1067
2016-08-12 2016-06-30 13F ALKERMES COMMON STOCK G01767105 454,490 165,808 57.44 19,643 99.02 0.1652
2016-05-13 2016-03-31 13F ALKERMES COMMON STOCK G01767105 288,682 209,803 265.98 9,870 57.64 0.0951
2016-02-10 2015-12-31 13F ALKERMES COMMON STOCK G01767105 78,879 -106,836 -57.53 6,261 -42.54 0.0587
2015-11-12 2015-09-30 13F ALKERMES COMMON STOCK G01767105 185,715 -9,633 -4.93 10,896 -13.31 0.1339
2015-08-14 2015-06-30 13F ALKERMES COMMON STOCK G01767105 195,348 117,885 152.18 12,569 166.12 0.1640
2015-05-11 2015-03-31 13F ALKERMES COMMON STOCK G01767105 77,463 77,463 0.00 4,723 0.0615
2015-02-17 2014-12-31 13F ALKERMES COMMON STOCK G01767105 0 -90,873 -100.00 0 -100.00
2014-11-13 2014-09-30 13F ALKERMES COMMON STOCK G01767105 90,873 44,449 95.75 3,896 66.78 0.0562
2014-08-14 2014-06-30 13F ALKERMES COMMON STOCK G01767105 46,424 37,924 446.16 2,336 522.93 0.0344
2014-05-14 2014-03-31 13F ALKERMES COMMON STOCK G01767105 8,500 1,500 21.43 375 86.57 0.0068
2013-08-06 2013-06-30 13F ALKERMES COMMON STOCK G01767105 7,000 7,000 201 0.0120
Legend
Shares
The total number of shares held by the institution at the end of the reporting period (the effective date). This is provided in the filing.
Value
The total value of the shares as of the effective date. This is provided in the filing.
Avg. Share Price
The weighted average share price of the shares held by the institution. We use FIFO accounting to determine this price
Class
This is the security class as indicated by the filer. There are a variety of values for this field. Common values include "EC" = equity common, "EP" - equity preferred
Allocation (%)
The percent of the institution's portfolio that this position represents. This is provided in NPORT filings. For 13F filings, we calculate it.
Change in Allocation
The change in allocation from the prior reporting period. This is calculated as current allocation - prior allocation.
Change in Allocation (%)
The percent change in allocation from the prior reporting period. This is calculated as (current allocation - prior allocation) / prior allocation.
Cost Basis
The total cost of the shares held. This is calculated as reported shares * avg. share price
Unrealized Gain/Loss
This is the market value of the position as of the effective date minus the cost basis.