Alnylam Pharmaceuticals, Inc.
DE ˙ XTRA ˙ US02043Q1076
260,50 € ↑8,70 (3,46%)
2026-06-04
DEL PRIS
SecurityDE:DUL / Alnylam Pharmaceuticals, Inc.
InstitutionJefferies Financial Group Inc.
Latest Disclosed Ownership25,553 shares
Latest Disclosed Value $ 8,454,721
Jefferies Financial Group Inc. ownership in DUL / Alnylam Pharmaceuticals, Inc.

On May 7, 2026 - Jefferies Financial Group Inc. filed a 13F-HR form disclosing ownership of 25,553 shares of Alnylam Pharmaceuticals, Inc. (DE:DUL) valued at $7,300,492 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 9, 2026 disclosing 26,322 shares of Alnylam Pharmaceuticals, Inc.. This represents a change in shares of -2.92% during the quarter. The current value of the position is $6,656,556 USD.

Jefferies Financial Group Inc. has a history of taking positions in derivatives of the underlying security (DUL) in the form of stock options. The firm currently holds call options representing 0 of underlying shares valued at $0 USD and put options representing 0 of underlying shares valued at $0 USD .

Note: prior versions of this page mistakenly stated that the share values represented the number of options, not the number of underlying shares. For more information on the data backing these reports, please see the SEC document Frequently Asked Questions About Form 13F.

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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Institutional Put/Call Ratios
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In addition to reporting standard equity and debt issues, institutions with more than 100MM assets under management must also disclose their put and call option holdings. Since put options generally indicate negative sentiment, and call options indicate positive sentiment, we can get a sense of the overall institutional sentiment by plotting the ratio of puts to calls. The chart to the right plots the historical put/call ratio for this instrument.

Using Put/Call Ratio as an indicator of investor sentiment overcomes one of the key deficiencies of using total institutional ownership, which is that a significant amount of assets under management are invested passively to track indices. Passively-managed funds do not typically buy options, so the put/call ratio indicator more closely tracks the sentiment of actively-managed funds.

DE:DUL / Alnylam Pharmaceuticals, Inc. Historical Put/Call Ratio
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)
2026-05-07 2026-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 25,553 -769 -2.92 8,455 -19.22 0.0579
2026-02-09 2025-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 26,322 9,780 59.12 10,467 38.75 0.0535
2025-11-13 2025-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 16,542 8,200 98.30 7,543 177.32 0.0356
2025-08-12 2025-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 8,342 -7,005 -45.64 2,720 -34.35 0.0229
2025-05-08 2025-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 15,347 15,347 4,144 0.0366
2025-02-27 2024-12-31 13F/A-1 ALNYLAM PHARMACEUTICALS COM 02043Q107 0 -47,193 -100.00 0 -100.00
2025-02-14 2024-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 0 0
2024-11-14 2024-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 47,193 44,893 1,951.87 12,979 2,225.99 0.0928
2024-08-13 2024-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 2,300 458 24.86 559 102.91 0.0059
2024-05-13 2024-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 1,842 1,696 1,161.64 275 918.52 0.0025
2024-05-06 2023-12-31 13F/A-1 ALNYLAM PHARMACEUTICALS COM 02043Q107 146 -4,632 -96.94 28 -96.81 0.0002
2024-02-14 2023-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 146 -4,632 28 0.0002
2023-11-14 2023-09-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 4,778 -5,129 -51.77 846 -55.02 0.0076
2023-08-14 2023-06-30 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 9,907 5,367 118.22 1,882 106.93 0.0169
2023-05-15 2023-03-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 4,540 -6,171 -57.61 909 -64.28 0.0074
2023-09-21 2022-12-31 13F/A-1 ALNYLAM PHARMACEUTICALS COM 02043Q107 10,711 10,711 2,545 0.0176
2023-02-14 2022-12-31 13F ALNYLAM PHARMACEUTICALS COM 02043Q107 12,427 12,427 2,539 0.0175
Disclosed Call Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share
Price
Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2025-02-27 2024-12-31 13F/A ALNYLAM PHARMACEUTICALS COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2025-02-14 2024-12-31 13F ALNYLAM PHARMACEUTICALS COM Call 0 0 n/a n/a n/a
2024-11-14 2024-09-30 13F ALNYLAM PHARMACEUTICALS COM Call 51,000 920.00 14,027 1,054.40 n/a n/a n/a
2024-08-13 2024-06-30 13F ALNYLAM PHARMACEUTICALS COM Call 5,000 0.00 1,215 62.65 n/a n/a n/a
2024-05-13 2024-03-31 13F ALNYLAM PHARMACEUTICALS COM Call 5,000 -64.29 747 -72.12 n/a n/a n/a
2024-05-06 2023-12-31 13F/A ALNYLAM PHARMACEUTICALS COM Call 14,000 -34.27 2,680 -28.98 n/a n/a n/a
2024-02-14 2023-12-31 13F ALNYLAM PHARMACEUTICALS COM Call 14,000 2,680 n/a n/a n/a
2023-11-14 2023-09-30 13F ALNYLAM PHARMACEUTICALS COM Call 21,300 -28.04 3,772 -32.91 n/a n/a n/a
2023-08-14 2023-06-30 13F ALNYLAM PHARMACEUTICALS COM Call 29,600 -41.96 5,622 -44.97 n/a n/a n/a
2023-05-15 2023-03-31 13F ALNYLAM PHARMACEUTICALS COM Call 51,000 94.66 10,216 64.09 n/a n/a n/a
2023-09-21 2022-12-31 13F/A ALNYLAM PHARMACEUTICALS COM Call 26,200 6,226 n/a n/a n/a
2023-02-14 2022-12-31 13F ALNYLAM PHARMACEUTICALS COM Call 26,200 6,226 n/a n/a n/a
Disclosed Put Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share Price Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2024-11-14 2024-09-30 13F ALNYLAM PHARMACEUTICALS COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2024-08-13 2024-06-30 13F ALNYLAM PHARMACEUTICALS COM Put 19,800 32.00 4,811 114.68 n/a n/a n/a
2024-05-13 2024-03-31 13F ALNYLAM PHARMACEUTICALS COM Put 15,000 500.00 2,242 368.83 n/a n/a n/a
2024-05-06 2023-12-31 13F/A ALNYLAM PHARMACEUTICALS COM Put 2,500 0.00 479 8.14 n/a n/a n/a
2024-02-14 2023-12-31 13F ALNYLAM PHARMACEUTICALS COM Put 2,500 479 n/a n/a n/a
2023-11-14 2023-09-30 13F ALNYLAM PHARMACEUTICALS COM Put 2,500 0.00 443 -6.75 n/a n/a n/a
2023-08-14 2023-06-30 13F ALNYLAM PHARMACEUTICALS COM Put 2,500 0.00 475 -5.20 n/a n/a n/a
2023-05-15 2023-03-31 13F ALNYLAM PHARMACEUTICALS COM Put 2,500 -89.67 501 -91.31 n/a n/a n/a
2023-09-21 2022-12-31 13F/A ALNYLAM PHARMACEUTICALS COM Put 24,200 5,751 n/a n/a n/a
2023-02-14 2022-12-31 13F ALNYLAM PHARMACEUTICALS COM Put 24,200 5,751 n/a n/a n/a
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.