Alnylam Pharmaceuticals, Inc.
DE ˙ XTRA ˙ US02043Q1076
251,80 € ↑6,70 (2,73%)
2026-06-03
DEL PRIS
SecurityDE:DUL / Alnylam Pharmaceuticals, Inc.
InstitutionOssiam
Latest Disclosed Ownership24,183 shares
Latest Disclosed Value $ 8,001,429
Ossiam reports 1,254.03% increase in ownership of DUL / Alnylam Pharmaceuticals, Inc.

On May 14, 2026 - Ossiam filed a 13F-HR form disclosing ownership of 24,183 shares of Alnylam Pharmaceuticals, Inc. (DE:DUL) valued at $6,909,083 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 13, 2026 disclosing 1,786 shares of Alnylam Pharmaceuticals, Inc.. This represents a change in shares of 1,254.03% during the quarter. The current value of the position is $6,089,279 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 ALNYLAM PHARMACEUTICALS COM 02043Q107 24,183 22,397 1,254.03 8,001 1,026.90 0.1407
2026-02-13 2025-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 1,786 230 14.78 710 0.14 0.0142
2025-11-14 2025-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 1,556 201 14.83 710 60.77 0.0091
2025-08-13 2025-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 1,355 19 1.42 442 22.50 0.0050
2025-05-14 2025-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 1,336 -1,091 -44.95 361 -36.95 0.0050
2025-02-13 2024-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 2,427 752 44.90 571 24.13 0.0099
2024-11-13 2024-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 1,675 509 43.65 461 62.54 0.0089
2024-08-13 2024-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 1,166 61 5.52 283 71.52 0.0054
2024-05-13 2024-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 1,105 -882 -44.39 165 -56.58 0.0029
2024-02-13 2023-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 1,987 0 0.00 380 8.26 0.0061
2023-11-14 2023-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 1,987 367 22.65 352 14.33 0.0062
2023-08-11 2023-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 1,620 783 93.55 308 83.83 0.0055
2023-05-12 2023-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 837 -30 -3.46 168 -18.93 0.0035
2023-02-13 2022-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 867 0 0.00 206 18.39 0.0053
2022-11-14 2022-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 867 867 174 0.0050
2021-11-12 2021-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 0 -1,376 -100.00 0 -100.00
2021-08-13 2021-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 1,376 1,376 246 0.0067
2020-02-14 2019-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 0 -572 -100.00 0 -100.00
2019-11-13 2019-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 572 572 46 0.0032
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.