Alnylam Pharmaceuticals, Inc.
DE ˙ XTRA ˙ US02043Q1076
251,80 € ↑6,70 (2,73%)
2026-06-03
DEL PRIS
SecurityDE:DUL / Alnylam Pharmaceuticals, Inc.
InstitutionCookson Peirce & Co Inc
Latest Disclosed Ownership1,060 shares
Latest Disclosed Value $ 350,723
Cookson Peirce & Co Inc reports 30.70% increase in ownership of DUL / Alnylam Pharmaceuticals, Inc.

On April 30, 2026 - Cookson Peirce & Co Inc filed a 13F-HR form disclosing ownership of 1,060 shares of Alnylam Pharmaceuticals, Inc. (DE:DUL) valued at $302,842 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 11, 2026 disclosing 811 shares of Alnylam Pharmaceuticals, Inc.. This represents a change in shares of 30.70% during the quarter. The current value of the position is $266,908 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)
2026-04-30 2026-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 1,060 249 30.70 351 8.70 0.0148
2026-02-11 2025-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 811 264 48.26 322 29.32 0.0134
2025-11-06 2025-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 547 547 249 0.0102
2022-07-20 2022-06-30 13F ALNYLAM PHARMACEUTICALS CS 02043Q107 0 -10,403 -100.00 0 -100.00
2022-05-03 2022-03-31 13F ALNYLAM PHARMACEUTICALS CS 02043Q107 10,403 675 6.94 1,699 2.97 0.0992
2022-01-31 2021-12-31 13F ALNYLAM PHARMACEUTICALS CS 02043Q107 9,728 500 5.42 1,650 -5.28 0.0919
2021-11-04 2021-09-30 13F ALNYLAM PHARMACEUTICALS CS 02043Q107 9,228 9,228 1,742 0.1061
2015-05-06 2015-03-31 13F ALNYLAM PHARMACEUTICALS CS 02043Q107 0 -2,535 -100.00 0 -100.00
2015-02-06 2014-12-31 13F ALNYLAM PHARMACEUTICALS CS 02043Q107 2,535 2,535 246 0.0510
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.