Ionis Pharmaceuticals, Inc.
US ˙ NasdaqGS ˙ US4622221004

SecurityIONS / Ionis Pharmaceuticals, Inc.
InstitutionD. E. Shaw & Co., Inc.
ManagerDE Shaw
Latest Disclosed Ownership429,599 shares
Latest Disclosed Value $ 32,258,589
D. E. Shaw & Co., Inc. ownership in IONS / Ionis Pharmaceuticals, Inc.

On May 15, 2026 - D. E. Shaw & Co., Inc. filed a 13F-HR form disclosing ownership of 429,599 shares of Ionis Pharmaceuticals, Inc. (US:IONS) valued at $32,258,589 USD as of March 31, 2026. The entity filed a previous 13F-HR on February 17, 2026 disclosing 332,803 shares of Ionis Pharmaceuticals, Inc.. This represents a change in shares of 29.09% during the quarter. The current value of the position is $31,712,998 USD.

D. E. Shaw & Co., Inc. 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.

Upgrade to unlock premium data and export to Excel .

Institutional Put/Call Ratios
(Premium Subscription Required)

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.

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 429,599 96,796 29.09 32,259 22.52 0.0142
2026-02-17 2025-12-31 13F IONIS PHARMACEUTICALS COM 462222100 332,803 -298,135 -47.25 26,328 -36.21 0.0144
2025-11-14 2025-09-30 13F IONIS PHARMACEUTICALS COM 462222100 630,938 630,938 41,276 0.0233
2025-05-15 2025-03-31 13F IONIS PHARMACEUTICALS COM 462222100 0 -23,123 -100.00 0 -100.00
2025-02-14 2024-12-31 13F IONIS PHARMACEUTICALS COM 462222100 23,123 -121,968 -84.06 808 -86.10 0.0006
2024-11-14 2024-09-30 13F IONIS PHARMACEUTICALS COM 462222100 145,091 -45,690 -23.95 5,812 -36.08 0.0050
2024-08-14 2024-06-30 13F IONIS PHARMACEUTICALS COM 462222100 190,781 30,299 18.88 9,093 30.71 0.0085
2024-05-15 2024-03-31 13F IONIS PHARMACEUTICALS COM 462222100 160,482 41,324 34.68 6,957 15.39 0.0060
2024-02-14 2023-12-31 13F IONIS PHARMACEUTICALS COM 462222100 119,158 -242,887 -67.09 6,028 -63.29 0.0053
2023-11-14 2023-09-30 13F IONIS PHARMACEUTICALS COM 462222100 362,045 165,832 84.52 16,422 104.00 0.0171
2023-08-14 2023-06-30 13F IONIS PHARMACEUTICALS COM 462222100 196,213 109,562 126.44 8,051 160.01 0.0082
2023-05-15 2023-03-31 13F IONIS PHARMACEUTICALS COM 462222100 86,651 -212,580 -71.04 3,097 -72.60 0.0033
2023-02-14 2022-12-31 13F IONIS PHARMACEUTICALS COM 462222100 299,231 89,786 42.87 11,302 21.99 0.0125
2022-11-14 2022-09-30 13F IONIS PHARMACEUTICALS COM 462222100 209,445 82,824 65.41 9,264 97.61 0.0111
2022-08-15 2022-06-30 13F IONIS PHARMACEUTICALS COM 462222100 126,621 126,621 4,688 0.0055
2022-05-16 2022-03-31 13F IONIS PHARMACEUTICALS COM 462222100 0 -160,659 -100.00 0 -100.00
2022-02-14 2021-12-31 13F IONIS PHARMACEUTICALS COM 462222100 160,659 34,553 27.40 4,889 15.58 0.0041
2021-11-15 2021-09-30 13F IONIS PHARMACEUTICALS COM 462222100 126,106 51,440 68.89 4,230 42.04 0.0038
2021-08-16 2021-06-30 13F IONIS PHARMACEUTICALS COM 462222100 74,666 66,560 821.12 2,978 718.13 0.0026
2021-05-17 2021-03-31 13F IONIS PHARMACEUTICALS COM 462222100 8,106 -5,311 -39.58 364 -52.04 0.0004
2021-02-16 2020-12-31 13F IONIS PHARMACEUTICALS COM 462222100 13,417 -209,732 -93.99 759 -92.83 0.0007
2020-11-16 2020-09-30 13F IONIS PHARMACEUTICALS COM 462222100 223,149 110,277 97.70 10,589 59.11 0.0108
2020-08-14 2020-06-30 13F IONIS PHARMACEUTICALS COM 462222100 112,872 87,876 351.56 6,655 463.03 0.0079
2020-05-15 2020-03-31 13F IONIS PHARMACEUTICALS COM 462222100 24,996 -524,362 -95.45 1,182 -96.44 0.0018
2020-02-14 2019-12-31 13F IONIS PHARMACEUTICALS COM 462222100 549,358 -280,132 -33.77 33,187 -33.22 0.0379
2019-11-14 2019-09-30 13F IONIS PHARMACEUTICALS COM 462222100 829,490 96,531 13.17 49,695 5.49 0.0612
2019-08-14 2019-06-30 13F IONIS PHARMACEUTICALS COM 462222100 732,959 175,768 31.55 47,107 4.16 0.0587
2019-05-15 2019-03-31 13F IONIS PHARMACEUTICALS COM 462222100 557,191 146,492 35.67 45,227 103.71 0.0584
2019-02-14 2018-12-31 13F IONIS PHARMACEUTICALS COM 462222100 410,699 294,184 252.49 22,202 269.42 0.0306
2018-11-14 2018-09-30 13F IONIS PHARMACEUTICALS COM 462222100 116,515 104,215 847.28 6,010 1,071.54 0.0072
2018-08-14 2018-06-30 13F IONIS PHARMACEUTICALS COM 462222100 12,300 -12,462 -50.33 513 -53.02 0.0007
2018-05-15 2018-03-31 13F IONIS PHARMACEUTICALS COM 462222100 24,762 -54,723 -68.85 1,092 -72.69 0.0015
2018-02-14 2017-12-31 13F IONIS PHARMACEUTICALS COM 462222100 79,485 12,917 19.40 3,998 18.46 0.0055
2017-11-14 2017-09-30 13F IONIS PHARMACEUTICALS COM 462222100 66,568 12,704 23.59 3,375 23.18 0.0052
2017-08-14 2017-06-30 13F IONIS PHARMACEUTICALS COM 462222100 53,864 33,048 158.76 2,740 227.36 0.0045
2017-05-15 2017-03-31 13F IONIS PHARMACEUTICALS COM 462222100 20,816 -45,788 -68.75 837 -73.73 0.0015
2017-02-14 2016-12-31 13F IONIS PHARMACEUTICALS COM 462222100 66,604 32,334 94.35 3,186 153.66 0.0054
2016-11-14 2016-09-30 13F IONIS PHARMACEUTICALS COM 462222100 34,270 -8,346 -19.58 1,256 26.49 0.0022
2016-08-15 2016-06-30 13F IONIS PHARMACEUTICALS COM 462222100 42,616 42,616 0.00 993 0.0018
2016-05-16 2016-03-31 13F ISIS PHARMACEUTICALS COM 464330109 0 -32,224 -100.00 0 -100.00
2016-02-16 2015-12-31 13F IONIS PHARMACEUTICALS COM 462222100 32,224 18,401 133.12 1,996 257.07 0.0030
2015-11-16 2015-09-30 13F ISIS PHARMACEUTICALS COM 464330109 13,823 -34,746 -71.54 559 -80.00 0.0008
2015-08-14 2015-06-30 13F ISIS PHARMACEUTICALS COM 464330109 48,569 12,492 34.63 2,795 21.68 0.0042
2015-05-15 2015-03-31 13F ISIS PHARMACEUTICALS COM 464330109 36,077 -1,748 -4.62 2,297 -1.63 0.0035
2015-02-17 2014-12-31 13F ISIS PHARMACEUTICALS COM 464330109 37,825 -4,700 -11.05 2,335 41.43 0.0030
2014-11-14 2014-09-30 13F ISIS PHARMACEUTICALS COM 464330109 42,525 15,497 57.34 1,651 77.34 0.0021
2014-08-14 2014-06-30 13F ISIS PHARMACEUTICALS COM 464330109 27,028 27,028 7.14 931 37.32 0.0013
2013-11-20 2013-09-30 13F/A-1 ISIS PHARMACEUTICALS COM 464330109 0 -25,227 -100.00 0 -100.00
2013-08-14 2013-06-30 13F ISIS PHARMACEUTICALS COM 464330109 25,227 25,227 678 0.0013
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
(%)
2021-05-17 2021-03-31 13F IONIS PHARMACEUTICALS COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2021-02-16 2020-12-31 13F IONIS PHARMACEUTICALS COM Call 38,900 0.00 2,199 19.12 n/a n/a n/a
2020-11-16 2020-09-30 13F IONIS PHARMACEUTICALS COM Call 38,900 0.00 1,846 -19.53 n/a n/a n/a
2020-08-14 2020-06-30 13F IONIS PHARMACEUTICALS COM Call 38,900 0.00 2,294 24.74 n/a n/a n/a
2020-05-15 2020-03-31 13F IONIS PHARMACEUTICALS COM Call 38,900 0.00 1,839 -21.74 n/a n/a n/a
2020-02-14 2019-12-31 13F IONIS PHARMACEUTICALS COM Call 38,900 0.00 2,350 0.86 n/a n/a n/a
2019-11-14 2019-09-30 13F IONIS PHARMACEUTICALS COM Call 38,900 0.00 2,330 -6.80 n/a n/a n/a
2019-08-14 2019-06-30 13F IONIS PHARMACEUTICALS COM Call 38,900 29.67 2,500 2.67 n/a n/a n/a
2019-05-15 2019-03-31 13F IONIS PHARMACEUTICALS COM Call 30,000 2,435 n/a n/a n/a
2016-05-16 2016-03-31 13F ISIS PHARMACEUTICALS COM Call 0 -100.00 0 -100.00 n/a n/a n/a
2016-02-16 2015-12-31 13F IONIS PHARMACEUTICALS COM Call 8,200 0.00 508 53.47 n/a n/a n/a
2015-11-16 2015-09-30 13F ISIS PHARMACEUTICALS COM Call 8,200 0.00 331 -29.87 n/a n/a n/a
2015-08-14 2015-06-30 13F ISIS PHARMACEUTICALS COM Call 8,200 -37.88 472 -43.81 n/a n/a n/a
2015-05-15 2015-03-31 13F ISIS PHARMACEUTICALS COM Call 13,200 -68.42 840 -67.45 n/a n/a n/a
2015-02-17 2014-12-31 13F ISIS PHARMACEUTICALS COM Call 41,800 13.59 2,581 80.62 n/a n/a n/a
2014-11-14 2014-09-30 13F ISIS PHARMACEUTICALS COM Call 36,800 -18.04 1,429 -7.63 n/a n/a n/a
2014-08-14 2014-06-30 13F ISIS PHARMACEUTICALS COM Call 44,900 -40.05 1,547 -52.19 n/a n/a n/a
2014-05-15 2014-03-31 13F ISIS PHARMACEUTICALS COM Call 74,900 55.39 3,236 68.54 n/a n/a n/a
2014-02-14 2013-12-31 13F ISIS PHARMACEUTICALS COM Call 48,200 20.50 1,920 27.83 n/a n/a n/a
2013-11-20 2013-09-30 13F/A ISIS PHARMACEUTICALS COM Call 40,000 1,502 n/a n/a n/a
2013-11-14 2013-09-30 13F ISIS PHARMACEUTICALS COM Call 40,000 1,502 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
(%)
2021-11-15 2021-09-30 13F IONIS PHARMACEUTICALS COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2021-08-16 2021-06-30 13F IONIS PHARMACEUTICALS COM Put 8,900 0.00 355 -11.25 n/a n/a n/a
2021-05-17 2021-03-31 13F IONIS PHARMACEUTICALS COM Put 8,900 0.00 400 -20.48 n/a n/a n/a
2021-02-16 2020-12-31 13F IONIS PHARMACEUTICALS COM Put 8,900 0.00 503 19.19 n/a n/a n/a
2020-11-16 2020-09-30 13F IONIS PHARMACEUTICALS COM Put 8,900 0.00 422 -19.62 n/a n/a n/a
2020-08-14 2020-06-30 13F IONIS PHARMACEUTICALS COM Put 8,900 525 n/a n/a n/a
2016-08-15 2016-06-30 13F IONIS PHARMACEUTICALS COM Put 0 -100.00 0 -100.00 n/a n/a n/a
2016-05-16 2016-03-31 13F IONIS PHARMACEUTICALS COM Put 31,500 235.11 1,276 119.24 n/a n/a n/a
2016-02-16 2015-12-31 13F IONIS PHARMACEUTICALS COM Put 9,400 0.00 582 53.16 n/a n/a n/a
2015-11-16 2015-09-30 13F ISIS PHARMACEUTICALS COM Put 9,400 -76.14 380 -83.24 n/a n/a n/a
2015-08-14 2015-06-30 13F ISIS PHARMACEUTICALS COM Put 39,400 34.93 2,267 21.95 n/a n/a n/a
2015-05-15 2015-03-31 13F ISIS PHARMACEUTICALS COM Put 29,200 -22.34 1,859 -19.91 n/a n/a n/a
2015-02-17 2014-12-31 13F ISIS PHARMACEUTICALS COM Put 37,600 0.00 2,321 58.97 n/a n/a n/a
2014-11-14 2014-09-30 13F ISIS PHARMACEUTICALS COM Put 37,600 -17.18 1,460 -6.65 n/a n/a n/a
2014-08-14 2014-06-30 13F ISIS PHARMACEUTICALS COM Put 45,400 20.74 1,564 -3.75 n/a n/a n/a
2014-05-15 2014-03-31 13F ISIS PHARMACEUTICALS COM Put 37,600 -42.77 1,625 -37.91 n/a n/a n/a
2014-02-14 2013-12-31 13F ISIS PHARMACEUTICALS COM Put 65,700 0.00 2,617 6.12 n/a n/a n/a
2013-11-20 2013-09-30 13F/A ISIS PHARMACEUTICALS COM Put 65,700 0.00 2,466 39.72 n/a n/a n/a
2013-11-14 2013-09-30 13F ISIS PHARMACEUTICALS COM Put 65,700 2,466 n/a n/a n/a
2013-08-14 2013-06-30 13F ISIS PHARMACEUTICALS COM Put 65,700 1,765 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.