Vanguard Portfolio Management filed a Schedule 13G with the SEC on October 30, 2026, disclosing beneficial ownership of 6,732,082 shares of Alnylam Pharmaceuticals Inc common stock as of September 30, 2026.

Key Highlights

  • Aggregate beneficial ownership: Vanguard Portfolio Management reported beneficial ownership of 6,732,082 shares of Alnylam Pharmaceuticals Inc common stock.
  • Percent of class: The reported position represents 5.03% of the outstanding class of common stock.
  • Sole dispositive power: Vanguard Portfolio Management holds sole power to dispose of all 6,732,082 shares reported.
  • Sole voting power: Sole voting power is held over only 34,162 shares, with shared voting power reported as zero.
  • Event date: The triggering event date for this filing is September 30, 2026.
  • Affiliated entities included: The filing covers securities beneficially owned by Vanguard Portfolio Management LLC and affiliates Vanguard Fiduciary Trust Company and Vanguard Global Advisers, LLC.

Vanguard Portfolio Management's 13G Disclosure for Alnylam Pharmaceuticals

According to the Schedule 13G filed on October 30, 2026, Vanguard Portfolio Management, organized in Pennsylvania and headquartered at 100 Vanguard Blvd, Malvern, PA 19355, disclosed beneficial ownership of 6,732,082 shares of common stock of Alnylam Pharmaceuticals Inc (NASDAQ:ALNY), whose principal executive offices are located at 675 West Kendall Street, Cambridge, MA 02142. The filing classifies Vanguard Portfolio Management as an investment adviser under the applicable SEC rule.

The filing reports that sole voting power extends to only 34,162 shares, while sole dispositive power covers the full 6,732,082 shares. Shared voting power and shared dispositive power are each reported as zero. According to the filing, the disclosed position represents 5.03% of the class. The filing states that investment companies registered under the Investment Company Act of 1940 and other managed accounts associated with Vanguard Portfolio Management have the right to receive or direct the receipt of dividends or sale proceeds from the reported securities, and that no single other person's interest in the reported securities exceeds 5%.

The filing notes, in accordance with SEC Release No. 34-39538 (January 12, 1998), that the Schedule 13G reflects securities beneficially owned or deemed to be beneficially owned by Vanguard Portfolio Management LLC together with affiliates Vanguard Fiduciary Trust Company and Vanguard Global Advisers, LLC. The filing further states that it does not include securities, if any, beneficially owned by other subsidiaries or affiliates whose ownership is disaggregated from that of the reporting business unit under that release. The document was signed by My Trieu-Gatt, identified as Authorized Signatory and Head of Global Fund Administration.

What Was Disclosed

Vanguard Portfolio Management filed a Schedule 13G reporting beneficial ownership of 6,732,082 shares, or 5.03%, of Alnylam Pharmaceuticals Inc common stock (CUSIP 02043Q107) as of September 30, 2026, with sole dispositive power over the full amount and sole voting power over 34,162 shares.