Ionis Pharmaceuticals, Inc.
US ˙ NasdaqGS ˙ US4622221004

SecurityIONS / Ionis Pharmaceuticals, Inc.
InstitutionDimensional Fund Advisors Lp
Latest Disclosed Ownership267,215 shares
Latest Disclosed Value $ 20,055,761
Dimensional Fund Advisors Lp reports 51.80% increase in ownership of IONS / Ionis Pharmaceuticals, Inc.

On May 7, 2026 - Dimensional Fund Advisors Lp filed a 13F-HR form disclosing ownership of 267,215 shares of Ionis Pharmaceuticals, Inc. (US:IONS) valued at $20,065,174 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 12, 2026 disclosing 176,035 shares of Ionis Pharmaceuticals, Inc.. This represents a change in shares of 51.80% during the quarter. The current value of the position is $19,725,811 USD.

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 267,215 91,180 51.80 20,056 44.02 0.0009
2026-02-12 2025-12-31 13F IONIS PHARMACEUTICALS COM 462222100 176,035 133,818 316.98 13,925 404.35 0.0029
2025-11-12 2025-09-30 13F IONIS PHARMACEUTICALS COM 462222100 42,217 42,217 2,762 0.0006
2025-05-13 2025-03-31 13F IONIS PHARMACEUTICALS COM 462222100 0 -94,157 -100.00 0 -100.00
2025-02-13 2024-12-31 13F IONIS PHARMACEUTICALS COM 462222100 94,157 -175 -0.19 3,292 -12.89 0.0008
2024-11-07 2024-09-30 13F IONIS PHARMACEUTICALS COM 462222100 94,332 5,586 6.29 3,779 -10.66 0.0009
2024-08-09 2024-06-30 13F IONIS PHARMACEUTICALS COM 462222100 88,746 -20,557 -18.81 4,230 -10.74 0.0011
2024-05-10 2024-03-31 13F IONIS PHARMACEUTICALS COM 462222100 109,303 -15,914 -12.71 4,738 -25.20 0.0013
2024-02-07 2023-12-31 13F IONIS PHARMACEUTICALS COM 462222100 125,217 -66,943 -34.84 6,335 -27.33 0.0018
2023-11-09 2023-09-30 13F IONIS PHARMACEUTICALS COM 462222100 192,160 9,446 5.17 8,716 16.28 0.0029
2023-08-09 2023-06-30 13F IONIS PHARMACEUTICALS COM 462222100 182,714 -260,171 -58.74 7,497 -52.63 0.0024
2023-05-12 2023-03-31 13F IONIS PHARMACEUTICALS COM 462222100 442,885 -15,559 -3.39 15,826 92,994.12 0.0053
2023-02-09 2022-12-31 13F IONIS PHARMACEUTICALS COM 462222100 458,444 -102,484 -18.27 17 -99.93 0.0051
2022-11-10 2022-09-30 13F IONIS PHARMACEUTICALS COM 462222100 560,928 -24,120 -4.12 24,810 14.55 0.0095
2022-08-12 2022-06-30 13F IONIS PHARMACEUTICALS COM 462222100 585,048 231,567 65.51 21,658 65.47 0.0078
2022-05-13 2022-03-31 13F IONIS PHARMACEUTICALS COM 462222100 353,481 -33,210 -8.59 13,089 11.23 0.0040
2022-02-09 2021-12-31 13F IONIS PHARMACEUTICALS COM 462222100 386,691 30,852 8.67 11,767 -1.41 0.0036
2021-11-12 2021-09-30 13F IONIS PHARMACEUTICALS COM 462222100 355,839 -54,378 -13.26 11,935 -27.06 0.0038
2021-08-12 2021-06-30 13F IONIS PHARMACEUTICALS COM 462222100 410,217 -47,064 -10.29 16,362 -20.43 0.0052
2021-05-14 2021-03-31 13F IONIS PHARMACEUTICALS COM 462222100 457,281 8,177 1.82 20,563 -19.03 0.0068
2021-03-08 2020-12-31 13F/A-2 IONIS PHARMACEUTICALS COM 462222100 449,104 -2,214 -0.49 25,396 18.56 0.0092
2021-02-11 2020-12-31 13F IONIS PHARMACEUTICALS COM 462222100 449,104 -2,214 25,396 9,171.6853
2020-11-12 2020-09-30 13F IONIS PHARMACEUTICALS COM 462222100 451,318 32,247 7.69 21,420 -13.31 0.0091
2020-08-13 2020-06-30 13F IONIS PHARMACEUTICALS COM 462222100 419,071 70,499 20.23 24,710 49.92 0.0109
2020-05-14 2020-03-31 13F IONIS PHARMACEUTICALS COM 462222100 348,572 45,043 14.84 16,482 -10.11 0.0086
2020-02-14 2019-12-31 13F IONIS PHARMACEUTICALS COM 462222100 303,529 22,744 8.10 18,336 9.01 0.0067
2019-11-12 2019-09-30 13F IONIS PHARMACEUTICALS COM 462222100 280,785 7,434 2.72 16,820 -4.27 0.0065
2019-08-13 2019-06-30 13F IONIS PHARMACEUTICALS COM 462222100 273,351 -31,226 -10.25 17,570 -28.92 0.0068
2019-08-12 2019-03-31 13F/A-2 IONIS PHARMACEUTICALS COM 462222100 304,577 11,709 4.00 24,720 56.19 0.0098
2019-05-10 2019-03-31 13F IONIS PHARMACEUTICALS COM 462222100 304,577 11,709 24,720
2019-02-26 2018-12-31 13F/A-1 IONIS PHARMACEUTICALS COM 462222100 292,868 24,169 8.99 15,827 14.19 0.0072
2019-02-13 2018-12-31 13F IONIS PHARMACEUTICALS COM 462222100 292,868 24,169 15,827
2018-11-13 2018-09-30 13F IONIS PHARMACEUTICALS COM 462222100 268,699 31,081 13.08 13,860 39.97 0.0053
2018-08-10 2018-06-30 13F IONIS PHARMACEUTICALS COM 462222100 237,618 37 0.02 9,902 -5.45 0.0039
2018-05-11 2018-03-31 13F IONIS PHARMACEUTICALS COM 462222100 237,581 12,770 5.68 10,473 -7.39 0.0044
2018-02-12 2017-12-31 13F IONIS PHARMACEUTICALS COM 462222100 224,811 20,789 10.19 11,309 9.30 0.0047
2017-11-13 2017-09-30 13F IONIS PHARMACEUTICALS COM 462222100 204,022 7,210 3.66 10,347 3.33 0.0045
2017-08-11 2017-06-30 13F IONIS PHARMACEUTICALS COM 462222100 196,812 26,496 15.56 10,014 46.25 0.0046
2017-05-12 2017-03-31 13F IONIS PHARMACEUTICALS COM 462222100 170,316 72,975 74.97 6,847 47.06 0.0033
2017-02-09 2016-12-31 13F IONIS PHARMACEUTICALS COM 462222100 97,341 76,259 361.73 4,656 503.11 0.0023
2016-11-10 2016-09-30 13F IONIS PHARMACEUTICALS COM 462222100 21,082 9,268 78.45 772 180.73 0.0004
2016-08-09 2016-06-30 13F IONIS PHARMACEUTICALS COM 462222100 11,814 -99,593 -89.40 275 -93.90 0.0002
2016-05-13 2016-03-31 13F IONIS PHARMACEUTICALS COM 462222100 111,407 14,191 14.60 4,510 -25.08 0.0027
2016-02-10 2015-12-31 13F IONIS PHARMACEUTICALS COM 462222100 97,216 -6,706 -6.45 6,020 43.44 0.0038
2015-11-13 2015-09-30 13F ISIS PHARMACEUTICALS COM 464330109 103,922 -8,883 -7.87 4,197 -35.34 0.0028
2015-08-14 2015-06-30 13F ISIS PHARMACEUTICALS COM 464330109 112,805 -2,744 -2.37 6,491 -11.77 0.0040
2015-05-14 2015-03-31 13F ISIS PHARMACEUTICALS COM 464330109 115,549 746 0.65 7,357 3.80 0.0046
2015-02-06 2014-12-31 13F ISIS PHARMACEUTICALS COM 464330109 114,803 36,331 46.30 7,088 132.39 0.0047
2014-11-13 2014-09-30 13F ISIS PHARMACEUTICALS COM 464330109 78,472 -23,182 -22.80 3,050 -12.96 0.0022
2014-08-08 2014-06-30 13F ISIS PHARMACEUTICALS COM 464330109 101,654 -160,663 -61.25 3,504 -69.08 0.0024
2014-05-14 2014-03-31 13F ISIS PHARMACEUTICALS COM 464330109 262,317 600 0.23 11,332 8.68 0.0085
2014-02-12 2013-12-31 13F ISIS PHARMACEUTICALS COM 464330109 261,717 -1,846 -0.70 10,427 5.38 0.0081
2013-11-13 2013-09-30 13F ISIS PHARMACEUTICALS COM 464330109 263,563 542 0.21 9,895 40.00 0.0086
2013-08-15 2013-06-30 13F ISIS PHARMACEUTICALS COM 464330109 263,021 263,021 7,068 0.0067
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.