Alnylam Pharmaceuticals, Inc.
DE ˙ XTRA ˙ US02043Q1076
260,50 € ↑8,70 (3,46%)
2026-06-04
DEL PRIS
SecurityDE:DUL / Alnylam Pharmaceuticals, Inc.
InstitutionRafferty Asset Management, LLC
Latest Disclosed Ownership50,553 shares
Latest Disclosed Value $ 16,726,471
Rafferty Asset Management, LLC reports 12.26% increase in ownership of DUL / Alnylam Pharmaceuticals, Inc.

On May 15, 2026 - Rafferty Asset Management, LLC filed a 13F-HR form disclosing ownership of 50,553 shares of Alnylam Pharmaceuticals, Inc. (DE:DUL) valued at $14,442,992 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 45,031 shares of Alnylam Pharmaceuticals, Inc.. This represents a change in shares of 12.26% during the quarter. The current value of the position is $13,169,056 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)
2026-05-15 2026-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 50,553 5,522 12.26 16,726 -6.59 0.0679
2026-02-13 2025-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 45,031 27,880 162.56 17,907 128.98 0.0619
2025-11-12 2025-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 17,151 -15,045 -46.73 7,821 -25.51 0.0254
2025-08-14 2025-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 32,196 -12,389 -27.79 10,499 -12.79 0.0346
2025-05-14 2025-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 44,585 -8,232 -15.59 12,039 -3.14 0.0513
2025-02-14 2024-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 52,817 -11,014 -17.25 12,428 -29.21 0.0440
2024-11-13 2024-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 63,831 -17,279 -21.30 17,555 -10.93 0.0601
2024-08-13 2024-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 81,110 19,904 32.52 19,710 115.47 0.0732
2024-05-13 2024-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 61,206 8,398 15.90 9,147 -9.50 0.0341
2024-02-13 2023-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 52,808 8,640 19.56 10,108 29.21 0.0426
2023-11-13 2023-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 44,168 615 1.41 7,822 -5.44 0.0460
2023-08-11 2023-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 43,553 5,362 14.04 8,272 8.13 0.0466
2023-05-11 2023-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 38,191 1,888 5.20 7,650 -11.32 0.0518
2023-02-13 2022-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 36,303 3,411 10.37 8,627 31.03 0.0722
2022-11-14 2022-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 32,892 1,702 5.46 6,584 44.74 0.0701
2022-08-12 2022-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 31,190 -5,845 -15.78 4,549 -24.77 0.0419
2022-05-13 2022-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 37,035 5,090 15.93 6,047 11.63 0.0358
2022-02-10 2021-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 31,945 15,515 94.43 5,417 74.63 0.0285
2021-11-10 2021-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 16,430 621 3.93 3,102 15.75 0.0212
2021-08-10 2021-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 15,809 -7,619 -32.52 2,680 -18.98 0.0169
2021-05-10 2021-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 23,428 16,239 225.89 3,308 254.18 0.0226
2021-02-10 2020-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 7,189 -9,017 -55.64 934 -60.42 0.0091
2020-11-13 2020-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 16,206 6,263 62.99 2,360 60.22 0.0285
2020-08-07 2020-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 9,943 5,863 143.70 1,473 231.76 0.0208
2020-05-15 2020-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 4,080 -29,417 -87.82 444 -88.49 0.0186
2020-02-10 2019-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 33,497 -44,138 -56.85 3,858 -38.20 0.0593
2019-11-14 2019-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 77,635 6,858 9.69 6,243 21.55 0.0976
2019-08-09 2019-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 70,777 11,052 18.50 5,136 -7.97 0.0903
2019-05-15 2019-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 59,725 59,725 5,581 0.0898
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.