Ionis Pharmaceuticals, Inc.
MX ˙ BMV ˙ US4622221004
SecurityMX:IONS / Ionis Pharmaceuticals, Inc.
InstitutionFred Alger Management, Llc
Latest Disclosed Ownership28,452 shares
Latest Disclosed Value $ 2,136,461
Fred Alger Management, Llc reports 25.95% decrease in ownership of IONS / Ionis Pharmaceuticals, Inc.

On May 15, 2026 - Fred Alger Management, Llc filed a 13F-HR form disclosing ownership of 28,452 shares of Ionis Pharmaceuticals, Inc. (MX:IONS) valued at $2,136,461 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 38,423 shares of Ionis Pharmaceuticals, Inc.. This represents a change in shares of -25.95% 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)
2026-05-15 2026-03-31 13F Ionis Pharmaceuticals Equity 462222100 28,452 -9,971 -25.95 2,136 -29.71 0.0060
2026-02-17 2025-12-31 13F Ionis Pharmaceuticals Equity 462222100 38,423 -3,978 -9.38 3,040 9.59 0.0119
2025-11-14 2025-09-30 13F Ionis Pharmaceuticals Equity 462222100 42,401 32,937 348.02 2,774 643.43 0.0108
2025-08-14 2025-06-30 13F Ionis Pharmaceuticals Equity 462222100 9,464 9,464 374 0.0017
2024-05-15 2024-03-31 13F IONIS PHARMACEUTICALS Common 462222100 0 -24,054 -100.00 0 -100.00
2024-02-14 2023-12-31 13F IONIS PHARMACEUTICALS Common 462222100 24,054 10,488 77.31 1,217 97.72 0.0066
2023-11-14 2023-09-30 13F IONIS PHARMACEUTICALS Common 462222100 13,566 13,566 615 0.0033
2023-11-14 2023-09-30 13F IONIS PHARMACEUTICALS Common 462222100 13,566 615
2023-08-14 2023-06-30 13F IONIS PHARMACEUTICALS Common 462222100 0 -499 -100.00 0 -100.00
2023-05-16 2023-03-31 13F/A-1 IONIS PHARMACEUTICALS Common 462222100 499 -189,854 -99.74 18 -99.76 0.0001
2023-05-15 2023-03-31 13F IONIS PHARMACEUTICALS Common 462222100 499 -189,854 18 0.0001
2023-02-14 2022-12-31 13F IONIS PHARMACEUTICALS Common 462222100 190,353 47,831 33.56 7,190 14.04 0.0390
2022-11-15 2022-09-30 13F IONIS PHARMACEUTICALS Common 462222100 142,522 -4,134 -2.82 6,304 16.12 0.0319
2022-08-15 2022-06-30 13F IONIS PHARMACEUTICALS Common 462222100 146,656 146,656 5,429 0.0254
2020-02-14 2019-12-31 13F IONIS PHARMACEUTICALS Common 462222100 0 -190 -100.00 0 -100.00
2019-11-14 2019-09-30 13F IONIS PHARMACEUTICALS Common 462222100 190 -240 -55.81 11 -60.71 0.0000
2019-08-14 2019-06-30 13F IONIS PHARMACEUTICALS Common 462222100 430 189 78.42 28 40.00 0.0001
2019-05-14 2019-03-31 13F IONIS PHARMACEUTICALS Common 462222100 241 241 20 0.0001
2018-07-19 2018-06-30 13F IONIS PHARMACEUTICALS Common 462222100 0 -4,000 -100.00 0 -100.00
2018-05-10 2018-03-31 13F IONIS PHARMACEUTICALS Common 462222100 4,000 4,000 176 0.0008
2017-05-15 2017-03-31 13F IONIS PHARMACEUTICALS Common 462222100 0 -6,000 -100.00 0 -100.00
2017-02-14 2016-12-31 13F IONIS PHARMACEUTICALS Common 462222100 6,000 6,000 287 0.0016
2015-08-14 2015-06-30 13F ISIS PHARMACEUTICALS Common 464330109 0 -161,972 -100.00 0 -100.00
2015-05-15 2015-03-31 13F ISIS PHARMACEUTICALS Common 464330109 161,972 -125,107 -43.58 10,313 -41.81 0.0464
2015-02-17 2014-12-31 13F ISIS PHARMACEUTICALS Common 464330109 287,079 143,042 99.31 17,724 216.90 0.0853
2014-11-14 2014-09-30 13F ISIS PHARMACEUTICALS Common 464330109 144,037 -30,413 -17.43 5,593 -6.94 0.0272
2014-08-14 2014-06-30 13F ISIS PHARMACEUTICALS Common 464330109 174,450 -156,405 -47.27 6,010 -57.96 0.0296
2014-05-15 2014-03-31 13F ISIS PHARMACEUTICALS Common 464330109 330,855 48,395 17.13 14,296 27.04 0.0709
2014-02-14 2013-12-31 13F ISIS PHARMACEUTICALS Common 464330109 282,460 282,460 11,253 0.0574
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.