Alnylam Pharmaceuticals, Inc.
DE ˙ XTRA ˙ US02043Q1076
251,80 € ↑6,70 (2,73%)
2026-06-03
DEL PRIS
SecurityDE:DUL / Alnylam Pharmaceuticals, Inc.
InstitutionDeerfield Management Company, L.p. (series C)
Latest Disclosed Ownership67,935 shares
Latest Disclosed Value $ 22,477,653
Deerfield Management Company, L.p. (series C) ownership in DUL / Alnylam Pharmaceuticals, Inc.

On May 15, 2026 - Deerfield Management Company, L.p. (series C) filed a 13F-HR form disclosing ownership of 67,935 shares of Alnylam Pharmaceuticals, Inc. (DE:DUL) valued at $19,409,030 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 67,935 shares of Alnylam Pharmaceuticals, Inc.. This represents a change in shares of 0.00% during the quarter. The current value of the position is $17,106,033 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 67,935 0 0.00 22,478 -16.79 0.2652
2026-02-17 2025-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 67,935 0 0.00 27,014 -12.80 0.3450
2025-11-14 2025-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 67,935 -77,065 -53.15 30,978 -34.48 0.4729
2025-08-14 2025-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 145,000 0 0.00 47,283 20.77 0.8582
2025-05-15 2025-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 145,000 -191 -0.13 39,153 14.60 0.7730
2025-02-14 2024-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 145,191 191 0.13 34,165 -14.33 0.6471
2024-11-14 2024-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 145,000 25,200 21.04 39,879 36.99 0.5959
2024-08-14 2024-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 119,800 119,800 29,111 0.4843
2024-05-15 2024-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 0 -1,574 -100.00 0 -100.00
2024-02-14 2023-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 1,574 1,574 301 0.0056
2018-11-14 2018-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 0 -146,000 -100.00 0 -100.00
2018-08-14 2018-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 146,000 0 0.00 14,380 -17.30 0.5050
2018-05-15 2018-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 146,000 146,000 17,389 0.6025
2016-11-14 2016-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 0 -336,000 -100.00 0 -100.00
2016-08-15 2016-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 336,000 336,000 0.00 18,645 0.7328
2014-11-14 2014-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 0 -100,000 -100.00 0 -100.00
2014-08-14 2014-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 100,000 -202,000 -66.89 6,317 -68.84 0.2540
2014-05-15 2014-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 302,000 302,000 -21.18 20,276 -17.33 0.8278
2014-02-14 2013-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 0 -383,158 -100.00 0 -100.00
2013-11-14 2013-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 383,158 -310,842 -44.79 24,526 14.00 1.1407
2013-08-14 2013-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 694,000 694,000 21,514 1.0140
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.