Alkermes plc
US ˙ NasdaqGS ˙ IE00B56GVS15

SecurityALKS / Alkermes plc
InstitutionRhumbline Advisers
Latest Disclosed Ownership449,531 shares
Latest Disclosed Value $ 15,895,386
Rhumbline Advisers reports 2.35% increase in ownership of ALKS / Alkermes plc

On May 12, 2026 - Rhumbline Advisers filed a 13F-HR form disclosing ownership of 449,531 shares of Alkermes plc (US:ALKS) valued at $15,895,416 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 439,195 shares of Alkermes plc. This represents a change in shares of 2.35% during the quarter. The current value of the position is $19,221,946 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)
2026-05-12 2026-03-31 13F ALKERMES PLC SHS COM G01767105 449,531 10,336 2.35 15,895 29.35 0.0136
2026-02-13 2025-12-31 13F ALKERMES PLC SHS COM G01767105 439,195 -34,642 -7.31 12,289 -13.56 0.0099
2025-11-06 2025-09-30 13F ALKERMES PLC SHS COM G01767105 473,837 980 0.21 14,215 5.08 0.0114
2025-08-12 2025-06-30 13F ALKERMES PLC SHS COM G01767105 472,857 17,660 3.88 13,528 -9.99 0.0116
2025-05-29 2025-03-31 13F/A-1 ALKERMES PLC SHS COM G01767105 455,197 -9,517 -2.05 15,031 12.46 0.0141
2025-04-08 2025-03-31 13F ALKERMES PLC SHS COM G01767105 455,197 -9,517 15,031 0.0141
2025-05-29 2024-12-31 13F/A-1 ALKERMES PLC SHS COM G01767105 464,714 1,683 0.36 13,365 3.13 0.0120
2025-01-30 2024-12-31 13F ALKERMES PLC SHS COM G01767105 464,714 1,683 13,365 0.0120
2024-11-12 2024-09-30 13F ALKERMES PLC SHS COM G01767105 463,031 -34,282 -6.89 12,960 8.14 0.0117
2024-08-01 2024-06-30 13F ALKERMES PLC SHS COM G01767105 497,313 7,722 1.58 11,985 -9.57 0.0113
2024-05-09 2024-03-31 13F ALKERMES PLC SHS COM G01767105 489,591 3,653 0.75 13,253 -1.68 0.0127
2024-02-08 2023-12-31 13F ALKERMES PLC SHS COM G01767105 485,938 247,802 104.06 13,480 102.08 0.0141
2023-11-09 2023-09-30 13F ALKERMES PLC SHS COM G01767105 238,136 4,098 1.75 6,670 -8.94 0.0077
2023-08-08 2023-06-30 13F ALKERMES PLC SHS COM G01767105 234,038 4,753 2.07 7,325 121,983.33 0.0082
2023-05-11 2023-03-31 13F ALKERMES PLC SHS COM G01767105 229,285 1,248 0.55 6 -99.90 0.0080
2023-02-14 2022-12-31 13F ALKERMES PLC SHS COM G01767105 228,037 11,718 5.42 5,959 23.37 0.0080
2022-11-10 2022-09-30 13F ALKERMES PLC SHS COM G01767105 216,319 15,756 7.86 4,830 -19.16 0.0072
2022-08-11 2022-06-30 13F ALKERMES PLC SHS COM G01767105 200,563 27,967 16.20 5,975 31.58 0.0087
2022-05-12 2022-03-31 13F ALKERMES PLC SHS COM G01767105 172,596 9,020 5.51 4,541 19.34 0.0058
2022-02-10 2021-12-31 13F ALKERMES PLC SHS COM G01767105 163,576 -2,070 -1.25 3,805 -25.52 0.0047
2021-11-12 2021-09-30 13F ALKERMES PLC SHS COM G01767105 165,646 3,008 1.85 5,109 28.11 0.0069
2021-08-05 2021-06-30 13F ALKERMES PLC SHS COM G01767105 162,638 -1,133 -0.69 3,988 30.37 0.0052
2021-05-06 2021-03-31 13F ALKERMES PLC SHS COM G01767105 163,771 -8,105 -4.72 3,059 -10.79 0.0042
2021-02-10 2020-12-31 13F ALKERMES PLC SHS COM G01767105 171,876 6,865 4.16 3,429 25.42 0.0047
2020-11-12 2020-09-30 13F ALKERMES PLC SHS COM G01767105 165,011 -4,458 -2.63 2,734 -16.87 0.0043
2020-08-13 2020-06-30 13F ALKERMES PLC SHS COM G01767105 169,469 9,249 5.77 3,289 42.38 0.0055
2020-05-06 2020-03-31 13F ALKERMES PLC SHS COM G01767105 160,220 37,001 30.03 2,310 -8.11 0.0048
2020-02-05 2019-12-31 13F ALKERMES PLC SHS COM G01767105 123,219 1,571 1.29 2,514 5.94 0.0042
2019-10-23 2019-09-30 13F ALKERMES PLC SHS COM G01767105 121,648 2,110 1.77 2,373 -11.92 0.0043
2019-08-14 2019-06-30 13F ALKERMES PLC SHS COM G01767105 119,538 -30,057 -20.09 2,694 -50.65 0.0051
2019-05-01 2019-03-31 13F ALKERMES PLC SHS COM G01767105 149,595 -742 -0.49 5,459 23.06 0.0106
2019-01-31 2018-12-31 13F ALKERMES PLC SHS COM G01767105 150,337 -9,340 -5.85 4,436 -34.54 0.0097
2018-11-07 2018-09-30 13F ALKERMES PLC SHS COM G01767105 159,677 -4,080 -2.49 6,777 0.55 0.0131
2018-08-06 2018-06-30 13F ALKERMES PLC SHS COM G01767105 163,757 3,236 2.02 6,740 -27.56 0.0136
2018-05-02 2018-03-31 13F ALKERMES PLC SHS COM G01767105 160,521 -5,597 -3.37 9,304 2.33 0.0194
2018-02-09 2017-12-31 13F ALKERMES PLC SHS COM G01767105 166,118 -6,022 -3.50 9,092 3.88 0.0185
2017-11-06 2017-09-30 13F ALKERMES PLC SHS COM G01767105 172,140 -4,173 -2.37 8,752 -14.37 0.0190
2017-08-02 2017-06-30 13F ALKERMES PLC SHS COM G01767105 176,313 -4,983 -2.75 10,221 -3.63 0.0233
2017-05-02 2017-03-31 13F ALKERMES PLC SHS COM G01767105 181,296 6,412 3.67 10,606 9.12 0.0248
2017-01-27 2016-12-31 13F ALKERMES PLC SHS COM G01767105 174,884 13,933 8.66 9,720 28.40 0.0246
2016-11-08 2016-09-30 13F ALKERMES PLC SHS COM G01767105 160,951 8,372 5.49 7,570 14.80 0.0209
2016-08-11 2016-06-30 13F ALKERMES PLC SHS COM G01767105 152,579 11,935 8.49 6,594 37.12 0.0195
2016-05-02 2016-03-31 13F ALKERMES PLC USD. COM G01767105 140,644 -1,860 -1.31 4,809 -57.49 0.0149
2016-02-03 2015-12-31 13F ALKERMES PLC USD. COM G01767105 142,504 2,220 1.58 11,312 37.45 0.0364
2015-11-04 2015-09-30 13F ALKERMES PLC USD. COM G01767105 140,284 7,828 5.91 8,230 -3.43 0.0280
2015-08-04 2015-06-30 13F ALKERMES PLC USD. COM G01767105 132,456 6,692 5.32 8,522 11.14 0.0272
2015-05-12 2015-03-31 13F ALKERMES PLC USD. COM G01767105 125,764 2,275 1.84 7,668 6.03 0.0221
2015-02-06 2014-12-31 13F ALKERMES PLC USD. COM G01767105 123,489 -1,745 -1.39 7,232 34.70 0.0210
2014-11-12 2014-09-30 13F ALKERMES PLC USD. COM G01767105 125,234 -6,723 -5.09 5,369 -19.15 0.0161
2014-08-06 2014-06-30 13F ALKERMES PLC USD. COM G01767105 131,957 17,074 14.86 6,641 31.12 0.0195
2014-05-06 2014-03-31 13F ALKERMES PLC USD. COM G01767105 114,883 4,010 3.62 5,065 12.36 0.0150
2014-02-03 2013-12-31 13F ALKERMES PLC USD. COM G01767105 110,873 -9,480 -7.88 4,508 11.42 0.0133
2013-11-05 2013-09-30 13F ALKERMES PLC USD. COM G01767105 120,353 -24,248 -16.77 4,046 -2.44 0.0125
2013-08-07 2013-06-30 13F ALKERMES PLC USD. COM G01767105 144,601 144,601 4,147 0.0133
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.