Ionis Pharmaceuticals, Inc.
MX ˙ BMV ˙ US4622221004
SecurityMX:IONS / Ionis Pharmaceuticals, Inc.
InstitutionMillennium Management Llc
ManagerIsrael Englander
Latest Disclosed Ownership1,051,506 shares
Latest Disclosed Value $ 78,957,586
Millennium Management Llc ownership in IONS / Ionis Pharmaceuticals, Inc.

On May 15, 2026 - Millennium Management Llc filed a 13F-HR form disclosing ownership of 1,051,506 shares of Ionis Pharmaceuticals, Inc. (MX:IONS) valued at $78,957,586 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 93,262 shares of Ionis Pharmaceuticals, Inc.. This represents a change in shares of 1,027.48% during the quarter.

Millennium Management Llc has a history of taking positions in derivatives of the underlying security (IONS) in the form of stock options. The firm currently holds call options representing 0 of underlying shares valued at $0 USD and put options representing 0 of underlying shares valued at $0 USD .

Note: prior versions of this page mistakenly stated that the share values represented the number of options, not the number of underlying shares. For more information on the data backing these reports, please see the SEC document Frequently Asked Questions About Form 13F.

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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Institutional Put/Call Ratios
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In addition to reporting standard equity and debt issues, institutions with more than 100MM assets under management must also disclose their put and call option holdings. Since put options generally indicate negative sentiment, and call options indicate positive sentiment, we can get a sense of the overall institutional sentiment by plotting the ratio of puts to calls. The chart to the right plots the historical put/call ratio for this instrument.

Using Put/Call Ratio as an indicator of investor sentiment overcomes one of the key deficiencies of using total institutional ownership, which is that a significant amount of assets under management are invested passively to track indices. Passively-managed funds do not typically buy options, so the put/call ratio indicator more closely tracks the sentiment of actively-managed funds.

MX:IONS / Ionis Pharmaceuticals, Inc. Historical Put/Call Ratio
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 COM 462222100 1,051,506 958,244 1,027.48 78,958 970.31 0.0329
2026-02-17 2025-12-31 13F IONIS PHARMACEUTICALS COM 462222100 93,262 -686,308 -88.04 7,378 -85.54 0.0031
2025-11-14 2025-09-30 13F IONIS PHARMACEUTICALS COM 462222100 779,570 -1,869,957 -70.58 50,999 -51.28 0.0218
2025-08-14 2025-06-30 13F IONIS PHARMACEUTICALS COM 462222100 2,649,527 2,014,157 317.01 104,683 446.10 0.0506
2025-05-15 2025-03-31 13F IONIS PHARMACEUTICALS COM 462222100 635,370 -138,845 -17.93 19,169 -29.18 0.0102
2025-02-14 2024-12-31 13F IONIS PHARMACEUTICALS COM 462222100 774,215 343,492 79.75 27,067 56.87 0.0132
2024-11-14 2024-09-30 13F IONIS PHARMACEUTICALS COM 462222100 430,723 302,508 235.94 17,255 182.39 0.0082
2024-08-14 2024-06-30 13F IONIS PHARMACEUTICALS COM 462222100 128,215 -454,964 -78.01 6,111 -75.83 0.0028
2024-05-15 2024-03-31 13F IONIS PHARMACEUTICALS COM 462222100 583,179 -307,146 -34.50 25,281 -43.87 0.0108
2024-02-14 2023-12-31 13F IONIS PHARMACEUTICALS COM 462222100 890,325 453,202 103.68 45,042 127.17 0.0195
2023-11-14 2023-09-30 13F IONIS PHARMACEUTICALS COM 462222100 437,123 18,210 4.35 19,828 15.35 0.0100
2023-08-14 2023-06-30 13F IONIS PHARMACEUTICALS COM 462222100 418,913 373,550 823.47 17,188 960.33 0.0085
2023-05-15 2023-03-31 13F IONIS PHARMACEUTICALS COM 462222100 45,363 -70,143 -60.73 1,621 -62.85 0.0009
2023-02-14 2022-12-31 13F IONIS PHARMACEUTICALS COM 462222100 115,506 96,577 510.21 4,363 421.27 0.0024
2022-11-14 2022-09-30 13F IONIS PHARMACEUTICALS COM 462222100 18,929 -301,686 -94.10 837 -92.95 0.0005
2022-08-15 2022-06-30 13F IONIS PHARMACEUTICALS COM 462222100 320,615 129,424 67.69 11,869 67.59 0.0074
2022-05-16 2022-03-31 13F IONIS PHARMACEUTICALS COM 462222100 191,191 -1,431,947 -88.22 7,082 -85.66 0.0038
2022-02-14 2021-12-31 13F IONIS PHARMACEUTICALS COM 462222100 1,623,138 1,340,284 473.84 49,392 420.63 0.0251
2021-11-15 2021-09-30 13F IONIS PHARMACEUTICALS COM 462222100 282,854 -512,988 -64.46 9,487 -70.12 0.0057
2021-08-16 2021-06-30 13F IONIS PHARMACEUTICALS COM 462222100 795,842 164,578 26.07 31,746 11.85 0.0195
2021-05-17 2021-03-31 13F IONIS PHARMACEUTICALS COM 462222100 631,264 100,675 18.97 28,382 -5.39 0.0203
2021-02-16 2020-12-31 13F IONIS PHARMACEUTICALS COM 462222100 530,589 421,632 386.97 30,000 480.27 0.0217
2020-11-16 2020-09-30 13F IONIS PHARMACEUTICALS COM 462222100 108,957 95,588 715.00 5,170 556.09 0.0064
2020-08-14 2020-06-30 13F IONIS PHARMACEUTICALS COM 462222100 13,369 -58,223 -81.33 788 -76.72 0.0011
2020-05-14 2020-03-31 13F IONIS PHARMACEUTICALS COM 462222100 71,592 61,528 611.37 3,385 456.74 0.0076
2020-02-14 2019-12-31 13F IONIS PHARMACEUTICALS COM 462222100 10,064 -45,141 -81.77 608 -81.61 0.0008
2019-11-14 2019-09-30 13F IONIS PHARMACEUTICALS COM 462222100 55,205 -135,739 -71.09 3,307 -73.05 0.0052
2019-08-15 2019-06-30 13F/A-1 IONIS PHARMACEUTICALS COM 462222100 190,944 25,905 15.70 12,272 -8.39 0.0184
2019-08-14 2019-06-30 13F VICTORY CAP HLDGS COM CL A 462222100 29,974 -155,087 544
2019-05-14 2019-03-31 13F IONIS PHARMACEUTICALS COM 462222100 165,039 81,561 97.70 13,396 196.83 0.0200
2019-02-15 2018-12-31 13F/A-1 IONIS PHARMACEUTICALS COM 462222100 83,478 -44,849 -34.95 4,513 -31.82 0.0070
2019-02-14 2018-12-31 13F IONIS PHARMACEUTICALS COM 462222100 83,478 4,513
2018-11-14 2018-09-30 13F IONIS PHARMACEUTICALS COM 462222100 128,327 -53,607 -29.47 6,619 -12.69 0.0081
2018-08-14 2018-06-30 13F IONIS PHARMACEUTICALS COM 462222100 181,934 -90,903 -33.32 7,581 -36.97 0.0099
2018-05-15 2018-03-31 13F IONIS PHARMACEUTICALS COM 462222100 272,837 76,920 39.26 12,027 22.04 0.0160
2018-02-14 2017-12-31 13F IONIS PHARMACEUTICALS COM 462222100 195,917 2,874 1.49 9,855 0.69 0.0136
2017-11-14 2017-09-30 13F IONIS PHARMACEUTICALS COM 462222100 193,043 96,324 99.59 9,787 98.92 0.0149
2017-08-14 2017-06-30 13F IONIS PHARMACEUTICALS COM 462222100 96,719 -152,610 -61.21 4,920 -50.91 0.0088
2017-05-15 2017-03-31 13F IONIS PHARMACEUTICALS COM 462222100 249,329 244,954 5,598.95 10,023 4,695.69 0.0184
2017-02-14 2016-12-31 13F IONIS PHARMACEUTICALS COM 462222100 4,375 -1,601,931 -99.73 209 -99.64 0.0004
2016-11-14 2016-09-30 13F IONIS PHARMACEUTICALS COM 462222100 1,606,306 1,606,306 0.00 58,855 0.0987
2016-08-15 2016-06-30 13F IONIS PHARMACEUTICALS COM 462222100 0 -1,078,089 -100.00 0 -100.00
2016-05-16 2016-03-31 13F IONIS PHARMACEUTICALS COM 462222100 1,078,089 1,078,089 43,663 0.1091
2016-02-16 2015-12-31 13F ISIS PHARMACEUTICALS COM 464330109 0 -180,814 -100.00 0 -100.00
2015-11-16 2015-09-30 13F ISIS PHARMACEUTICALS COM 464330109 180,814 -187,242 -50.87 7,309 -65.49 0.0142
2015-08-14 2015-06-30 13F ISIS PHARMACEUTICALS COM 464330109 368,056 361,256 5,312.59 21,182 4,791.92 0.0401
2015-05-15 2015-03-31 13F ISIS PHARMACEUTICALS COM 464330109 6,800 6,800 433 0.0008
2014-11-14 2014-09-30 13F ISIS PHARMACEUTICALS COM 464330109 0 -198,138 -100.00 0 -100.00
2014-08-14 2014-06-30 13F ISIS PHARMACEUTICALS COM 464330109 198,138 -10,243 -4.92 6,826 -24.19 0.0189
2014-05-15 2014-03-31 13F ISIS PHARMACEUTICALS COM 464330109 208,381 168,381 420.95 9,004 464.87 0.0261
2014-02-14 2013-12-31 13F ISIS PHARMACEUTICALS COM 464330109 40,000 -220,133 -84.62 1,594 -83.68 0.0050
2013-11-14 2013-09-30 13F ISIS PHARMACEUTICALS COM 464330109 260,133 -554,185 -68.06 9,765 -55.37 0.0314
2013-08-14 2013-06-30 13F ISIS PHARMACEUTICALS COM 464330109 814,318 814,318 21,881 0.0671
Disclosed Call Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share
Price
Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2021-08-16 2021-06-30 13F IONIS PHARMACEUTICALS COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2021-05-17 2021-03-31 13F IONIS PHARMACEUTICALS COM Call 100,000 4,496 n/a n/a n/a
2020-05-14 2020-03-31 13F IONIS PHARMACEUTICALS COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2020-02-14 2019-12-31 13F IONIS PHARMACEUTICALS COM Call 100,000 -33.33 6,041 -32.77 n/a n/a n/a
2019-11-14 2019-09-30 13F IONIS PHARMACEUTICALS COM Call 150,000 8,986 n/a n/a n/a
2017-08-14 2017-06-30 13F IONIS PHARMACEUTICALS COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2017-05-15 2017-03-31 13F IONIS PHARMACEUTICALS COM Call 565,900 22,749 n/a n/a n/a
2015-08-14 2015-06-30 13F ISIS PHARMACEUTICALS COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2015-05-15 2015-03-31 13F ISIS PHARMACEUTICALS COM Call 11,700 25.81 745 100.81 n/a n/a n/a
2014-02-14 2013-12-31 13F ISIS PHARMACEUTICALS COM Call 9,300 371 n/a n/a n/a
Disclosed Put Options
File
Date
Effective
Date
Form Security Class ID Opt Avg Share Price Shares ΔShares
(%)
Value
(x1000)
ΔValue
(%)
Prior Allocation
(%)
Allocation
(%)
ΔAllocation
(%)
Cost Basis
(x1000)
Profit
(x1000)
Return
(%)
2019-11-14 2019-09-30 13F IONIS PHARMACEUTICALS COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2019-08-15 2019-06-30 13F/A IONIS PHARMACEUTICALS COM Put 200,000 0.00 12,854 -20.82 n/a n/a n/a
2019-05-14 2019-03-31 13F IONIS PHARMACEUTICALS COM Put 200,000 16,234 n/a n/a n/a
2017-08-14 2017-06-30 13F IONIS PHARMACEUTICALS COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2017-05-15 2017-03-31 13F IONIS PHARMACEUTICALS COM Put 200,000 8,040 n/a n/a n/a
2015-08-14 2015-06-30 13F ISIS PHARMACEUTICALS COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2015-05-15 2015-03-31 13F ISIS PHARMACEUTICALS COM Put 11,000 34.15 700 114.07 n/a n/a n/a
2014-02-14 2013-12-31 13F ISIS PHARMACEUTICALS COM Put 8,200 327 n/a n/a n/a
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.