Ionis Pharmaceuticals INC Schedule 13G passive stakes

T. Rowe Price Investment Management, Inc. has filed a Schedule 13G, reporting beneficial ownership of 6,159,027 shares, representing 3.7% of the outstanding common stock of Ionis Pharmaceuticals Inc.

Vanguard Capital Management has reported beneficial ownership of over 8.3 million shares, representing 5.05% of Ionis Pharmaceuticals' common stock as of March 31, 2026.

The Vanguard Group has filed an amended Schedule 13G, reporting 0% beneficial ownership in Ionis Pharmaceuticals Inc. following an internal realignment.

Capital World Investors has reported an 11.1% beneficial ownership stake in Ionis Pharmaceuticals, Inc., holding 17,961,299 shares of common stock.

T. Rowe Price Investment Management, Inc. has filed an Amendment No. 3 to its Schedule 13G, disclosing an 8.3% beneficial ownership stake in Ionis Pharmaceuticals Inc. common stock as of September 30, 2025.

Wellington Management Group LLP and its affiliates have reduced their beneficial ownership in Ionis Pharmaceuticals, Inc. to 4.3% of common stock, as disclosed in an amended Schedule 13G filing.

BlackRock, Inc. has filed an Amendment No. 3 to its Schedule 13G, disclosing a beneficial ownership of 5.7% of the common stock of IONIS PHARMACEUTICALS INC as of March 31, 2025.

Capital World Investors has reported a 7.3% beneficial ownership stake in Ionis Pharmaceuticals, Inc., holding 11,465,413 shares of common stock as of December 31, 2024.

T. Rowe Price Investment Management, Inc. has filed an amended Schedule 13G, reporting beneficial ownership of 10.0% of Ionis Pharmaceuticals Inc.'s common stock.

The Vanguard Group has filed an Amendment No. 13 to its Schedule 13G, reporting a 10.43% beneficial ownership stake in Ionis Pharmaceuticals Inc. as of December 31, 2024.