Ionis Pharmaceuticals, Inc.
MX ˙ BMV ˙ US4622221004
SecurityMX:IONS / Ionis Pharmaceuticals, Inc.
InstitutionGrandfield & Dodd, Llc
Latest Disclosed Ownership37,326 shares
Latest Disclosed Value $ 2,802,809
Grandfield & Dodd, Llc reports 1.31% decrease in ownership of IONS / Ionis Pharmaceuticals, Inc.

On May 7, 2026 - Grandfield & Dodd, Llc filed a 13F-HR form disclosing ownership of 37,326 shares of Ionis Pharmaceuticals, Inc. (MX:IONS) valued at $2,802,809 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 10, 2026 disclosing 37,821 shares of Ionis Pharmaceuticals, Inc.. This represents a change in shares of -1.31% 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)
2026-05-07 2026-03-31 13F IONIS PHARMACEUTICALS COM 462222100 37,326 -495 -1.31 2,803 -6.35 0.1582
2026-02-10 2025-12-31 13F IONIS PHARMACEUTICALS COM 462222100 37,821 146 0.39 2,992 21.43 0.1695
2025-10-30 2025-09-30 13F IONIS PHARMACEUTICALS COM 462222100 37,675 445 1.20 2,465 67.62 0.1398
2025-08-08 2025-06-30 13F IONIS PHARMACEUTICALS COM 462222100 37,230 -531 -1.41 1,471 29.06 0.0861
2025-05-02 2025-03-31 13F IONIS PHARMACEUTICALS COM 462222100 37,761 1,874 5.22 1,139 -9.17 0.0706
2025-02-06 2024-12-31 13F IONIS PHARMACEUTICALS COM 462222100 35,887 1,074 3.09 1,255 -10.04 0.0774
2024-11-08 2024-09-30 13F IONIS PHARMACEUTICALS COM 462222100 34,813 760 2.23 1,395 -14.06 0.0826
2024-08-09 2024-06-30 13F IONIS PHARMACEUTICALS COM 462222100 34,053 279 0.83 1,623 10.79 0.1027
2024-05-06 2024-03-31 13F IONIS PHARMACEUTICALS COM 462222100 33,774 670 2.02 1,464 -12.54 0.0924
2024-01-31 2023-12-31 13F IONIS PHARMACEUTICALS COM 462222100 33,104 242 0.74 1,675 12.35 0.1157
2023-10-26 2023-09-30 13F IONIS PHARMACEUTICALS COM 462222100 32,862 183 0.56 1,491 11.19 0.1095
2023-08-08 2023-06-30 13F IONIS PHARMACEUTICALS COM 462222100 32,679 395 1.22 1,341 16.22 0.0937
2023-04-28 2023-03-31 13F IONIS PHARMACEUTICALS COM 462222100 32,284 810 2.57 1,154 -2.95 0.0806
2023-01-20 2022-12-31 13F IONIS PHARMACEUTICALS COM 462222100 31,474 2,403 8.27 1,189 -7.91 0.0870
2022-11-04 2022-09-30 13F IONIS PHARMACEUTICALS COM 462222100 29,071 795 2.81 1,290 22.86 0.1053
2022-08-01 2022-06-30 13F IONIS PHARMACEUTICALS COM 462222100 28,276 275 0.98 1,050 0.96 0.0827
2022-04-19 2022-03-31 13F IONIS PHARMACEUTICALS COM 462222100 28,001 1,230 4.59 1,040 28.40 0.0706
2022-02-08 2021-12-31 13F IONIS PHARMACEUTICALS COM 462222100 26,771 5,080 23.42 810 10.96 0.0521
2021-10-28 2021-09-30 13F IONIS PHARMACEUTICALS COM 462222100 21,691 638 3.03 730 -13.10 0.0510
2021-07-28 2021-06-30 13F IONIS PHARMACEUTICALS COM 462222100 21,053 700 3.44 840 -8.70 0.0581
2021-04-22 2021-03-31 13F IONIS PHARMACEUTICALS COM 462222100 20,353 711 3.62 920 -17.12 0.0688
2021-01-29 2020-12-31 13F IONIS PHARMACEUTICALS COM 462222100 19,642 605 3.18 1,110 23.33 0.0871
2020-11-03 2020-09-30 13F IONIS PHARMACEUTICALS COM 462222100 19,037 336 1.80 900 -18.18 0.0811
2020-07-24 2020-06-30 13F IONIS PHARMACEUTICALS COM 462222100 18,701 1,365 7.87 1,100 34.15 0.1064
2020-05-14 2020-03-31 13F IONIS PHARMACEUTICALS COM 462222100 17,336 660 3.96 820 -18.57 0.0967
2020-02-07 2019-12-31 13F IONIS PHARMACEUTICALS COM 462222100 16,676 855 5.40 1,007 6.22 0.0917
2019-10-30 2019-09-30 13F IONIS PHARMACEUTICALS COM 462222100 15,821 1,170 7.99 948 0.64 0.0933
2019-07-29 2019-06-30 13F IONIS PHARMACEUTICALS COM 462222100 14,651 808 5.84 942 -16.19 0.0931
2019-04-26 2019-03-31 13F IONIS PHARMACEUTICALS COM 462222100 13,843 99 0.72 1,124 51.28 0.1171
2019-02-12 2018-12-31 13F IONIS PHARMACEUTICALS COM 462222100 13,744 165 1.22 743 6.14 0.0879
2018-11-02 2018-09-30 13F IONIS PHARMACEUTICALS COM 462222100 13,579 110 0.82 700 24.78 0.0721
2018-07-27 2018-06-30 13F IONIS PHARMACEUTICALS COM 462222100 13,469 80 0.60 561 -4.92 0.0616
2018-05-04 2018-03-31 13F/A-1 IONIS PHARMACEUTICALS COM 462222100 13,389 -280 -2.05 590 -14.24 0.0658
2018-05-04 2018-03-31 13F IONIS PHARMACEUTICALS COM 462222100 13,389 -280 590
2018-02-05 2017-12-31 13F IONIS PHARMACEUTICALS COM 462222100 13,669 290 2.17 688 1.47 0.0734
2017-11-03 2017-09-30 13F IONIS PHARMACEUTICALS COM 462222100 13,379 570 4.45 678 3.99 0.0761
2017-07-27 2017-06-30 13F IONIS PHARMACEUTICALS COM 462222100 12,809 690 5.69 652 33.88 0.0770
2017-04-28 2017-03-31 13F IONIS PHARMACEUTICALS COM 462222100 12,119 135 1.13 487 -15.01 0.0602
2017-02-02 2016-12-31 13F IONIS PHARMACEUTICALS COM 462222100 11,984 1,580 15.19 573 50.39 0.0743
2016-10-24 2016-09-30 13F IONIS PHARMACEUTICALS COM 462222100 10,404 -780 -6.97 381 46.54 0.0501
2016-07-28 2016-06-30 13F IONIS PHARMACEUTICALS COM 462222100 11,184 2,574 29.90 260 -25.50 0.0364
2016-05-06 2016-03-31 13F IONIS PHARMACEUTICALS COM 462222100 8,610 3,235 60.19 349 4.80 0.0505
2016-02-03 2015-12-31 13F IONIS PHARMACEUTICALS COM 462222100 5,375 5,375 333 0.0506
2015-11-02 2015-09-30 13F ISIS PHARMACEUTICALS COM 464330109 0 -3,700 -100.00 0 -100.00
2015-08-03 2015-06-30 13F ISIS PHARMACEUTICALS COM 464330109 3,700 3,700 213 0.0326
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.