Alnylam Pharmaceuticals, Inc.
DE ˙ XTRA ˙ US02043Q1076
260,50 € ↑8,70 (3,46%)
2026-06-04
DEL PRIS
SecurityDE:DUL / Alnylam Pharmaceuticals, Inc.
InstitutionTwo Sigma Advisers, Lp
Latest Disclosed Ownership1,132,560 shares
Latest Disclosed Value $ 450,362,484
Two Sigma Advisers, Lp reports 26.90% increase in ownership of DUL / Alnylam Pharmaceuticals, Inc.

On February 17, 2026 - Two Sigma Advisers, Lp filed a 13F-HR form disclosing ownership of 1,132,560 shares of Alnylam Pharmaceuticals, Inc. (DE:DUL) valued at $382,692,024 USD as of December 31, 2025. The entity filed a previous 13F-HR on November 14, 2025 disclosing 892,500 shares of Alnylam Pharmaceuticals, Inc.. This represents a change in shares of 26.90% during the quarter. The current value of the position is $295,031,880 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)
2026-02-17 2025-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 1,132,560 240,060 26.90 450,362 10.66 0.8756
2025-11-14 2025-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 892,500 626,400 235.40 406,980 369.02 0.8144
2025-08-14 2025-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 266,100 -9,700 -3.52 86,773 16.52 0.1778
2025-05-15 2025-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 275,800 197,000 250.00 74,472 301.63 0.1677
2025-02-14 2024-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 78,800 -24,300 -23.57 18,542 -34.61 0.0429
2024-11-14 2024-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 103,100 -155,600 -60.15 28,356 -54.89 0.0664
2024-08-14 2024-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 258,700 69,100 36.45 62,864 121.86 0.1402
2024-05-15 2024-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 189,600 189,600 28,336 0.0656
2024-02-14 2023-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 0 -35,900 -100.00 0 -100.00
2023-11-14 2023-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 35,900 -157,700 -81.46 6,358 -82.71 0.0163
2023-08-14 2023-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 193,600 38,500 24.82 36,772 18.36 0.0937
2023-05-15 2023-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 155,100 35,100 29.25 31,070 8.95 0.0801
2023-02-14 2022-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 120,000 56,200 88.09 28,518 123.32 0.0796
2022-11-14 2022-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 63,800 51,400 414.52 12,770 605.91 0.0370
2022-08-15 2022-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 12,400 -34,300 -73.45 1,809 -76.28 0.0051
2022-05-16 2022-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 46,700 42,900 1,128.95 7,626 1,084.16 0.0203
2022-02-14 2021-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 3,800 3,800 644 0.0016
2021-08-16 2021-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 0 -31,900 -100.00 0 -100.00
2021-05-17 2021-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 31,900 28,200 762.16 4,504 836.38 0.0124
2021-02-16 2020-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 3,700 3,700 481 0.0013
2020-11-16 2020-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 0 -8,300 -100.00 0 -100.00
2020-09-15 2020-06-30 13F/A-1 ALNYLAM PHARMACEUTICALS COM 02043Q107 8,300 8,300 1,229 0.0036
2020-08-14 2020-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 8,300 8,300 1,229 3,551.4018
2019-08-14 2019-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 0 -70,800 -100.00 0 -100.00
2019-05-15 2019-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 70,800 -46,300 -39.54 6,616 -22.51 0.0167
2019-02-14 2018-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 117,100 -72,400 -38.21 8,538 -48.52 0.0233
2018-11-14 2018-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 189,500 -44,322 -18.96 16,585 -27.98 0.0405
2018-08-14 2018-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 233,822 -123,400 -34.54 23,029 -45.87 0.0619
2018-05-15 2018-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 357,222 248,200 227.66 42,545 207.16 0.1154
2018-02-14 2017-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 109,022 109,022 13,851 0.0373
2016-08-15 2016-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 0 -101,622 -100.00 0 -100.00
2016-05-16 2016-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 101,622 97,300 2,251.27 6,379 1,467.32 0.0357
2016-02-16 2015-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 4,322 4,322 0.00 407 0.0024
2015-11-16 2015-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 0 -5,022 -100.00 0 -100.00
2016-02-09 2015-06-30 13F/A-1 ALNYLAM PHARMACEUTICALS COM 02043Q107 5,022 -1,500 -23.00 602 -11.60 0.0046
2015-08-14 2015-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 5,022 602
2016-02-09 2015-03-31 13F/A-1 ALNYLAM PHARMACEUTICALS COM 02043Q107 6,522 -900 -12.13 681 -5.42 0.0052
2015-05-15 2015-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 6,522 681
2016-02-09 2014-12-31 13F/A-1 ALNYLAM PHARMACEUTICALS COM 02043Q107 7,422 7,422 720 0.0058
2015-02-17 2014-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 7,422 720 0.0058
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.