Alkermes plc
US ˙ NasdaqGS ˙ IE00B56GVS15

SecurityALKS / Alkermes plc
InstitutionSei Investments Co
Latest Disclosed Ownership190,717 shares
Latest Disclosed Value $ 5,336,304
Sei Investments Co reports 15.54% decrease in ownership of ALKS / Alkermes plc

On February 13, 2026 - Sei Investments Co filed a 13F-HR form disclosing ownership of 190,717 shares of Alkermes plc (US:ALKS) valued at $5,336,262 USD as of December 31, 2025. The entity filed a previous 13F-HR on November 13, 2025 disclosing 225,807 shares of Alkermes plc. This represents a change in shares of -15.54% during the quarter. The current value of the position is $8,155,059 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)
2026-02-13 2025-12-31 13F ALKERMES SHS G01767105 190,717 -35,090 -15.54 5,336 -21.23
2025-11-13 2025-09-30 13F ALKERMES SHS G01767105 225,807 8,901 4.10 6,774 9.17 0.0073
2025-08-14 2025-06-30 13F ALKERMES SHS G01767105 216,906 4,909 2.32 6,206 -7.46 0.0072
2025-05-14 2025-03-31 13F/A-1 ALKERMES SHS G01767105 211,997 136,603 181.19 6,706 209.27 0.0086
2025-05-13 2025-03-31 13F ALKERMES SHS G01767105 96,216 20,822 2,574 0.0028
2025-02-11 2024-12-31 13F ALKERMES SHS G01767105 75,394 828 1.11 2,168 3.88 0.0028
2024-11-12 2024-09-30 13F ALKERMES SHS G01767105 74,566 409 0.55 2,087 16.79 0.0027
2024-08-13 2024-06-30 13F ALKERMES SHS G01767105 74,157 -3,785 -4.86 1,787 -15.27 0.0025
2024-05-07 2024-03-31 13F ALKERMES SHS G01767105 77,942 7,178 10.14 2,110 7.49 0.0031
2024-02-14 2023-12-31 13F ALKERMES SHS G01767105 70,764 57 0.08 1,963 -0.91 0.0032
2023-11-14 2023-09-30 13F ALKERMES SHS G01767105 70,707 1,464 2.11 1,980 -8.25 0.0036
2023-08-11 2023-06-30 13F ALKERMES SHS G01767105 69,243 -13,895 -16.71 2,159 -7.66 0.0038
2023-05-12 2023-03-31 13F ALKERMES SHS G01767105 83,138 7,023 9.23 2,337 17.85 0.0043
2023-02-10 2022-12-31 13F ALKERMES SHS G01767105 76,115 -32,285 -29.78 1,984 -17.96 0.0044
2022-11-14 2022-09-30 13F ALKERMES SHS G01767105 108,400 -11,130 -9.31 2,417 -32.13 0.0054
2022-08-15 2022-06-30 13F ALKERMES SHS G01767105 119,530 54,243 83.08 3,561 107.28 0.0077
2022-05-13 2022-03-31 13F ALKERMES SHS G01767105 65,287 4,054 6.62 1,718 20.65 0.0035
2022-02-14 2021-12-31 13F ALKERMES SHS G01767105 61,233 -60,735 -49.80 1,424 -53.87 0.0027
2021-11-12 2021-09-30 13F ALKERMES SHS G01767105 121,968 33,871 38.45 3,087 42.65 0.0065
2021-08-06 2021-06-30 13F ALKERMES SHS G01767105 88,097 -24,602 -21.83 2,164 3.84 0.0048
2021-05-12 2021-03-31 13F ALKERMES SHS G01767105 112,699 -26,726 -19.17 2,084 -23.66 0.0053
2021-02-08 2020-12-31 13F ALKERMES SHS G01767105 139,425 -7,212 -4.92 2,730 12.11 0.0071
2020-12-04 2020-09-30 13F/A-1 ALKERMES SHS G01767105 146,637 40,673 38.38 2,435 19.77 0.0071
2020-11-06 2020-09-30 13F ALKERMES SHS G01767105 164,602 58,638 2,733 6,580.4563
2020-08-17 2020-06-30 13F/A-1 ALKERMES SHS G01767105 105,964 67,294 174.02 2,033 268.97 0.0063
2020-08-11 2020-06-30 13F ALKERMES SHS G01767105 55,126 16,456 1,094 2,967.5332
2020-05-14 2020-03-31 13F ALKERMES SHS G01767105 38,670 -10,183 -20.84 551 -44.51 0.0020
2020-02-06 2019-12-31 13F ALKERMES SHS G01767105 48,853 -52,745 -51.92 993 -49.90 0.0030
2019-11-12 2019-09-30 13F ALKERMES SHS G01767105 101,598 -1,513 -1.47 1,982 -14.72 0.0051
2019-08-14 2019-06-30 13F ALKERMES SHS G01767105 103,111 -28,980 -21.94 2,324 -51.78 0.0076
2019-05-15 2019-03-31 13F ALKERMES S3 G01767105 132,091 3,582 2.79 4,820 -11.62 0.0162
2019-02-13 2018-12-31 13F ALKERMES SHS G01767105 128,509 0 0.00 5,454 0.00 0.0194
2018-11-08 2018-09-30 13F ALKERMES SHS G01767105 128,509 961 0.75 5,454 3.89 0.0198
2018-08-03 2018-06-30 13F ALKERMES SHS G01767105 127,548 -3,362 -2.57 5,250 -30.81 0.0178
2018-05-11 2018-03-31 13F ALKERMES SHS G01767105 130,910 -109,677 -45.59 7,588 -42.37 0.0291
2018-02-08 2017-12-31 13F ALKERMES SHS G01767105 240,587 83,239 52.90 13,167 64.59 0.0457
2017-11-06 2017-09-30 13F ALKERMES SHS G01767105 157,348 38,570 32.47 8,000 16.18 0.0284
2017-07-31 2017-06-30 13F ALKERMES SHS G01767105 118,778 28,453 31.50 6,886 30.32 0.0275
2017-05-05 2017-03-31 13F ALKERMES SHS G01767105 90,325 22,228 32.64 5,284 39.57 0.0232
2017-02-02 2016-12-31 13F ALKERMES SHS G01767105 68,097 -20,128 -22.81 3,786 -8.77 0.0183
2016-11-04 2016-09-30 13F ALKERMES SHS G01767105 88,225 81,560 1,223.71 4,150 1,340.97 0.0211
2016-08-11 2016-06-30 13F ALKERMES SHS G01767105 6,665 -4,805 -41.89 288 -26.53 0.0017
2016-05-10 2016-03-31 13F/A-1 ALKERMES SHS G01767105 11,470 -6,391 -35.78 392 -72.34 0.0024
2016-02-03 2015-12-31 13F ALKERMES SHS G01767105 17,861 -2,179 -10.87 1,417 20.49 0.0086
2015-11-02 2015-09-30 13F/A-1 ALKERMES SHS G01767105 20,040 -21,755 -52.05 1,176 -56.27 0.0108
2015-10-30 2015-09-30 13F ALKERMES SHS G01767105 20,040 1,176
2015-08-07 2015-06-30 13F/A-1 ALKERMES SHS G01767105 41,795 -2,025 -4.62 2,689 0.56 0.0243
2015-08-04 2015-06-30 13F ALKERMES SHS G01767105 41,795 -2,025 2,689 0.0243
2015-05-14 2015-03-31 13F/A-1 ALKERMES SHS G01767105 43,820 -2,663 -5.73 2,674 -1.87 0.0232
2015-05-01 2015-03-31 13F ALKERMES SHS G01767105 43,820 2,674
2015-02-10 2014-12-31 13F ALKERMES SHS G01767105 46,483 46,483 2,725 0.0241
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.