Ionis Pharmaceuticals, Inc.
MX ˙ BMV ˙ US4622221004
SecurityMX:IONS / Ionis Pharmaceuticals, Inc.
InstitutionRockefeller Capital Management L.P.
Latest Disclosed Ownership4,155 shares
Latest Disclosed Value $ 311,999
Rockefeller Capital Management L.P. reports 52.42% increase in ownership of IONS / Ionis Pharmaceuticals, Inc.

On May 14, 2026 - Rockefeller Capital Management L.P. filed a 13F-HR form disclosing ownership of 4,155 shares of Ionis Pharmaceuticals, Inc. (MX:IONS) valued at $311,999 USD as of March 31, 2026. The entity filed a previous 13F-HR/A on March 16, 2026 disclosing 2,726 shares of Ionis Pharmaceuticals, Inc.. This represents a change in shares of 52.42% during the quarter.

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)
2026-05-14 2026-03-31 13F IONIS PHARMACEUTICALS COM 462222100 4,155 1,429 52.42 312 44.65 0.0006
2026-03-16 2025-12-31 13F/A-1 IONIS PHARMACEUTICALS COM 462222100 2,726 523 23.74 216 49.31 0.0004
2026-02-14 2025-12-31 13F IONIS PHARMACEUTICALS COM 462222100 2,726 523 216 0.0002
2025-11-14 2025-09-30 13F IONIS PHARMACEUTICALS COM 462222100 2,203 2,203 144 0.0003
2023-05-17 2023-03-31 13F IONIS PHARMACEUTICALS COM 462222100 0 -2,581 -100.00 0 -100.00
2023-03-06 2022-12-31 13F IONIS PHARMACEUTICALS COM 462222100 2,581 0 0.00 97 -14.91 0.0005
2022-11-02 2022-09-30 13F IONIS PHARMACEUTICALS COM 462222100 2,581 -7,270 -73.80 114 -68.60 0.0006
2022-08-12 2022-06-30 13F IONIS PHARMACEUTICALS COM 462222100 9,851 -1,405 -12.48 363 -12.74 0.0019
2022-05-13 2022-03-31 13F IONIS PHARMACEUTICALS COM 462222100 11,256 -836 -6.91 416 13.66 0.0020
2022-02-14 2021-12-31 13F IONIS PHARMACEUTICALS COM 462222100 12,092 -1,320,688 -99.09 366 -99.18 0.0017
2021-11-12 2021-09-30 13F IONIS PHARMACEUTICALS COM 462222100 1,332,780 8,169 0.62 44,699 -15.40 0.2349
2021-08-10 2021-06-30 13F IONIS PHARMACEUTICALS COM 462222100 1,324,611 590,632 80.47 52,837 60.12 0.2977
2021-05-11 2021-03-31 13F IONIS PHARMACEUTICALS COM 462222100 733,979 179,807 32.45 32,998 5.32 0.2233
2021-02-12 2020-12-31 13F IONIS PHARMACEUTICALS COM 462222100 554,172 -162,953 -22.72 31,331 -7.92 0.2373
2020-11-13 2020-09-30 13F IONIS PHARMACEUTICALS COM 462222100 717,125 1,245 0.17 34,026 -19.39 0.3187
2020-08-12 2020-06-30 13F IONIS PHARMACEUTICALS COM 462222100 715,880 45,742 6.83 42,209 33.22 0.4417
2020-05-12 2020-03-31 13F IONIS PHARMACEUTICALS COM 462222100 670,138 180,487 36.86 31,684 7.12 0.4156
2020-02-07 2019-12-31 13F IONIS PHARMACEUTICALS COM 462222100 489,651 485,973 13,212.97 29,579 13,345.00 0.3688
2019-11-12 2019-09-30 13F IONIS PHARMACEUTICALS COM 462222100 3,678 -865 -19.04 220 -24.66 0.0030
2019-08-09 2019-06-30 13F IONIS PHARMACEUTICALS COM 462222100 4,543 -3,034 -40.04 292 -52.52 0.0041
2019-05-10 2019-03-31 13F IONIS PHARMACEUTICALS COM 462222100 7,577 3,824 101.89 615 202.96 0.0088
2019-02-12 2018-12-31 13F IONIS PHARMACEUTICALS COM 462222100 3,753 0 0.00 203 4.64 0.0036
2018-11-02 2018-09-30 13F Ionis Pharmaceuticals Common 462222100 3,753 0 0.00 194 24.36 0.0029
2018-07-31 2018-06-30 13F Ionis Pharmaceuticals Common 462222100 3,753 3,753 156 0.0025
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.