Ionis Pharmaceuticals (IONS)
Ionis Pharmaceuticals on one page: short interest, daily short volume, fails to deliver, planned sales, large holders, 13F holders, financials, earnings dates and insider trades. Listed on Nasdaq, classified by the SEC as pharmaceutical preparations.
20.7M
Short interest
settlement 2026-10-15
7.7
Days to cover
+3.0 days vs prior
40.1%
Short share of volume
2026-10-28
5,975
Fails to deliver
settlement 2026-09-10
Mon 11 Jan
Next earnings
estimated date
$197K
Insider flow, 90 days
1 buys, 2 sells
As of 2026-10-28.
Short interest
FINRA, twice a month. The newest 48 settlements in the table, 48 in the chart. JSONAs of 15 October 2026, short interest in IONS is 20,653,026 shares, down 237,226 shares over the last month. Over the last 48 readings it ranged from 10,239,965 shares (15 January 2025) to 22,508,744 shares (30 September 2026). At the reported average volume of 2.7M shares a day that is 7.7 days to cover.
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| Settlement | Shares short | Change | Avg daily volume | Days to cover |
|---|---|---|---|---|
| 2026-10-15 | 20,653,026 | -8.2% | 2,698,710 | 7.65 |
| 2026-09-30 | 22,508,744 | +7.8% | 4,881,042 | 4.61 |
| 2026-09-15 | 20,890,252 | -0.2% | 4,017,153 | 5.20 |
| 2026-08-31 | 20,924,638 | +0.1% | 2,279,069 | 9.18 |
| 2026-08-14 | 20,909,181 | -2.6% | 2,172,496 | 9.62 |
| 2026-07-31 | 21,466,123 | +7.1% | 3,382,861 | 6.35 |
| 2026-07-15 | 20,042,879 | +15.0% | 5,450,805 | 3.68 |
| 2026-06-30 | 17,425,020 | -1.9% | 2,377,735 | 7.33 |
| 2026-06-15 | 17,757,362 | +4.5% | 1,668,579 | 10.64 |
| 2026-05-29 | 16,986,466 | +5.6% | 1,702,170 | 9.98 |
| 2026-05-15 | 16,086,234 | -1.2% | 1,608,774 | 10.00 |
| 2026-04-30 | 16,279,706 | +18.3% | 2,023,751 | 8.04 |
| 2026-04-15 | 13,762,159 | -4.0% | 1,443,237 | 9.54 |
| 2026-03-31 | 14,330,826 | +2.7% | 2,418,365 | 5.93 |
| 2026-03-13 | 13,949,702 | -9.0% | 2,453,957 | 5.68 |
| 2026-02-27 | 15,323,236 | -1.1% | 2,217,431 | 6.91 |
| 2026-02-13 | 15,487,922 | -0.3% | 1,851,249 | 8.37 |
| 2026-01-30 | 15,537,729 | +13.2% | 2,668,640 | 5.82 |
| 2026-01-15 | 13,729,783 | -7.8% | 2,082,127 | 6.59 |
| 2025-12-31 | 14,885,370 | -7.5% | 1,568,746 | 9.49 |
| 2025-12-15 | 16,086,183 | +2.9% | 2,020,355 | 7.96 |
| 2025-11-28 | 15,626,208 | +9.9% | 2,624,122 | 5.95 |
| 2025-11-14 | 14,223,973 | +12.3% | 3,736,097 | 3.81 |
| 2025-10-31 | 12,661,274 | -7.6% | 1,914,799 | 6.61 |
| 2025-10-15 | 13,699,358 | +11.6% | 2,279,250 | 6.01 |
| 2025-09-30 | 12,278,792 | +2.6% | 1,991,945 | 6.16 |
| 2025-09-15 | 11,972,594 | +14.0% | 4,802,271 | 2.49 |
| 2025-08-29 | 10,502,338 | -2.6% | 1,766,631 | 5.94 |
| 2025-08-15 | 10,785,168 | -6.9% | 2,150,609 | 5.01 |
| 2025-07-31 | 11,580,340 | -10.2% | 1,778,123 | 6.51 |
| 2025-07-15 | 12,889,193 | -8.8% | 2,201,808 | 5.85 |
| 2025-06-30 | 14,139,627 | -0.6% | 1,956,419 | 7.23 |
| 2025-06-13 | 14,225,565 | -4.1% | 1,430,495 | 9.94 |
| 2025-05-30 | 14,836,205 | -2.8% | 1,410,037 | 10.52 |
| 2025-05-15 | 15,266,156 | +4.3% | 1,630,549 | 9.36 |
| 2025-04-30 | 14,629,509 | +0.6% | 1,411,113 | 10.37 |
| 2025-04-15 | 14,547,282 | +9.1% | 2,356,410 | 6.17 |
| 2025-03-31 | 13,336,000 | +4.1% | 1,395,099 | 9.56 |
| 2025-03-14 | 12,814,848 | -0.3% | 1,708,250 | 7.50 |
| 2025-02-28 | 12,853,622 | +1.4% | 2,018,209 | 6.37 |
| 2025-02-14 | 12,673,485 | +4.5% | 1,340,248 | 9.46 |
| 2025-01-31 | 12,124,536 | +18.4% | 1,831,301 | 6.62 |
| 2025-01-15 | 10,239,965 | -6.1% | 1,408,358 | 7.27 |
| 2024-12-31 | 10,901,561 | +3.5% | 1,682,606 | 6.48 |
| 2024-12-13 | 10,528,956 | +0.8% | 1,379,548 | 7.63 |
| 2024-11-29 | 10,448,423 | -5.5% | 1,633,097 | 6.40 |
| 2024-11-15 | 11,050,361 | +2.9% | 1,195,779 | 9.24 |
| 2024-10-31 | 10,740,418 | +8.8% | 1,210,170 | 8.88 |
Daily short volume
FINRA Reg SHO, the last 30 sessions. JSONAs of 28 October 2026, the short share of IONS volume is 40.1%, down 8.3 points over the last five sessions. Over the last 30 readings it ranged from 8.8% (25 September 2026) to 56.5% (14 October 2026). The latest reading is 5.3 points above the 30-session average of 34.8%, on 729K shares reported.
| Date | Short volume | Total volume | Short share | Exempt |
|---|---|---|---|---|
| 2026-10-28 | 292K | 729K | 40.1% | 44 |
| 2026-10-27 | 236K | 513K | 46.1% | 0 |
| 2026-10-26 | 218K | 749K | 29.2% | 1,600 |
| 2026-10-23 | 453K | 1.1M | 39.7% | 221 |
| 2026-10-22 | 762K | 2.5M | 30.9% | 0 |
| 2026-10-21 | 420K | 867K | 48.4% | 0 |
| 2026-10-20 | 449K | 911K | 49.3% | 2,641 |
| 2026-10-19 | 417K | 817K | 51.0% | 35,800 |
| 2026-10-16 | 234K | 567K | 41.3% | 2,306 |
| 2026-10-15 | 345K | 829K | 41.6% | 40 |
| 2026-10-14 | 385K | 680K | 56.5% | 0 |
| 2026-10-13 | 284K | 768K | 37.0% | 8 |
| 2026-10-12 | 251K | 689K | 36.4% | 51 |
| 2026-10-09 | 817K | 3.4M | 23.9% | 271 |
| 2026-10-08 | 279K | 1.1M | 24.7% | 0 |
| 2026-10-07 | 335K | 820K | 40.9% | 16,200 |
| 2026-10-06 | 406K | 944K | 43.0% | 50,160 |
| 2026-10-05 | 258K | 1.0M | 25.0% | 58 |
| 2026-10-02 | 286K | 862K | 33.2% | 0 |
| 2026-10-01 | 227K | 923K | 24.6% | 330 |
| 2026-09-30 | 338K | 916K | 37.0% | 4,478 |
| 2026-09-29 | 415K | 2.1M | 19.9% | 42 |
| 2026-09-28 | 456K | 1.4M | 32.3% | 500 |
| 2026-09-25 | 254K | 2.9M | 8.8% | 0 |
| 2026-09-24 | 389K | 1.5M | 25.2% | 5 |
| 2026-09-23 | 435K | 1.5M | 29.5% | 150 |
| 2026-09-22 | 825K | 2.2M | 37.6% | 15,140 |
| 2026-09-21 | 973K | 2.1M | 47.2% | 15 |
| 2026-09-18 | 327K | 1.8M | 18.5% | 300 |
| 2026-09-17 | 423K | 1.6M | 25.9% | 1,217 |
Fails to deliver
SEC, the last 30 settlement dates with a fail. JSONAs of 10 September 2026, the fails-to-deliver balance in IONS is 5,975 shares, down 2,543 shares over the last settlement date. Over the last 30 readings it ranged from 2 shares (23 July 2026) to 42,698 shares (30 June 2026).
| Settlement | Shares failed | Price | Value |
|---|---|---|---|
| 2026-09-10 | 5,975 | $56.02 | $335K |
| 2026-09-09 | 8,518 | $56.71 | $483K |
| 2026-09-08 | 20 | $58.09 | $1K |
| 2026-09-04 | 14 | $58.13 | $814 |
| 2026-08-19 | 3,049 | $59.62 | $182K |
| 2026-08-18 | 15 | $58.63 | $879 |
| 2026-08-17 | 522 | $57.24 | $30K |
| 2026-08-14 | 200 | $55.87 | $11K |
| 2026-08-10 | 175 | $56.56 | $10K |
| 2026-08-06 | 1,952 | $54.19 | $106K |
| 2026-08-04 | 373 | $54.49 | $20K |
| 2026-08-03 | 157 | $51.77 | $8K |
| 2026-07-30 | 4,288 | $54.04 | $232K |
| 2026-07-28 | 156 | $55.96 | $9K |
| 2026-07-23 | 2 | $54.01 | $108 |
| 2026-07-20 | 3,118 | $54.39 | $170K |
| 2026-07-17 | 36 | $54.65 | $2K |
| 2026-07-16 | 3,002 | $54.73 | $164K |
| 2026-07-15 | 51 | $54.93 | $3K |
| 2026-07-14 | 44 | $56.75 | $2K |
| 2026-07-07 | 3,546 | $83.18 | $295K |
| 2026-07-06 | 1,248 | $81.80 | $102K |
| 2026-07-01 | 30,806 | $79.29 | $2.4M |
| 2026-06-30 | 42,698 | $80.69 | $3.4M |
| 2026-06-29 | 11,381 | $81.18 | $924K |
| 2026-06-25 | 1,864 | $76.52 | $143K |
| 2026-06-24 | 3 | $75.99 | $228 |
| 2026-06-23 | 7 | $75.89 | $531 |
| 2026-06-18 | 1,691 | $74.31 | $126K |
| 2026-06-17 | 25 | $73.09 | $2K |
Insider trades
SEC Form 4, newest first. JSONOver the last 90 days IONS insiders reported 1 open-market buy ($258K) against 2 sells ($61K), so the dollar flow leans toward buying. Latest filing: Swayze Eric (EVP Research) on 2026-10-16.
| Date | Insider | Title | Type | Shares | Price | Value | Owned after |
|---|---|---|---|---|---|---|---|
| 2026-10-16 | Swayze Eric | EVP Research | Sell | 53 | $43.54 | $2K | 390 |
| 2026-10-16 | Devers Shannon L. | EVP, Chief Human Resources Ofc | Sell | 1K | $43.54 | $59K | 18K |
| 2026-10-15 | Swayze Eric | EVP Research | Exercise or conversion | 125 | $0.00 | $0 | 443 |
| 2026-10-15 | Devers Shannon L. | EVP, Chief Human Resources Ofc | Exercise or conversion | 3K | $0.00 | $0 | 19K |
| 2026-08-31 | O'NEIL PATRICK R. | EVP CLO & General Counsel | Other transaction | 63 | $51.31 | $3K | 59K |
| 2026-08-31 | Monia Brett P | Chief Executive Officer | Other transaction | 98 | $51.31 | $5K | 243K |
| 2026-08-31 | Birchler Brian | EVP, Corp and Development Ops | Other transaction | 58 | $51.31 | $3K | 103K |
| 2026-08-31 | BENNETT C FRANK | EVP, Chief Scientific Officer | Other transaction | 110 | $51.31 | $6K | 60K |
| 2026-07-31 | Hayden Michael R | Director | Buy | 5K | $51.60 | $258K | 24K |
| 2026-07-30 | Hayden Michael R | Director | Buy | 15K | $53.38 | $801K | 19K |
| 2026-07-15 | HERMAN JOAN E | Director | Exercise or conversion | 5K | $0.00 | $0 | 51K |
| 2026-07-15 | BERTHELSEN SPENCER R | Director | Exercise or conversion | 5K | $0.00 | $0 | 161K |
| 2026-07-07 | Kordasiewicz Holly B. | EVP, Chief Development Officer | Sell | 362 | $84.30 | $31K | 22K |
| 2026-07-07 | Diaz Allene M. | Director | Sell | 10K | $85.42 | $864K | 4K |
| 2026-07-07 | Diaz Allene M. | Director | Exercise or conversion | 10K | $47.11 | $476K | 14K |
| 2026-07-07 | BENNETT C FRANK | EVP, Chief Scientific Officer | Sell | 15K | $85.46 | $1.3M | 0 |
| 2026-07-07 | BENNETT C FRANK | EVP, Chief Scientific Officer | Other transaction | 15K | $0.00 | $0 | 15K |
| 2026-07-07 | BENNETT C FRANK | EVP, Chief Scientific Officer | Sell | 6K | $83.58 | $463K | 75K |
| 2026-07-01 | KLEIN JOSEPH III | Director | Sell | 11K | $79.04 | $903K | 11K |
| 2026-07-01 | KLEIN JOSEPH III | Director | Sell | 99 | $79.45 | $8K | 22K |
| 2026-07-01 | KLEIN JOSEPH III | Director | Exercise or conversion | 12K | $39.94 | $460K | 23K |
| 2026-06-26 | Monia Brett P | Chief Executive Officer | Sell | 50K | $80.59 | $4.0M | 246K |
| 2026-06-26 | Monia Brett P | Chief Executive Officer | Exercise or conversion | 50K | $56.78 | $2.8M | 296K |
| 2026-06-26 | Schneider Eugene | EVP, Chf Clinical Develop Ofcr | Sell | 26K | $81.05 | $2.1M | 77K |
| 2026-06-26 | Schneider Eugene | EVP, Chf Clinical Develop Ofcr | Exercise or conversion | 26K | $60.89 | $1.6M | 103K |
| 2026-06-26 | O'NEIL PATRICK R. | EVP CLO & General Counsel | Sell | 3K | $80.00 | $246K | 61K |
| 2026-06-26 | Baroldi Joseph | EVP, Chief Business Officer | Sell | 6K | $80.16 | $452K | 5K |
| 2026-06-26 | Baroldi Joseph | EVP, Chief Business Officer | Exercise or conversion | 2K | $32.60 | $58K | 10K |
| 2026-06-26 | Baroldi Joseph | EVP, Chief Business Officer | Exercise or conversion | 4K | $56.78 | $220K | 9K |
| 2026-06-25 | Swayze Eric | EVP Research | Sell | 11K | $79.18 | $839K | 22K |
| 2026-06-25 | Monia Brett P | Chief Executive Officer | Sell | 21K | $78.49 | $1.7M | 246K |
| 2026-06-25 | Monia Brett P | Chief Executive Officer | Exercise or conversion | 21K | $32.60 | $687K | 267K |
| 2026-06-24 | Monia Brett P | Chief Executive Officer | Exercise or conversion | 15K | $32.60 | $475K | 260K |
| 2026-06-24 | Monia Brett P | Chief Executive Officer | Sell | 15K | $78.41 | $1.1M | 246K |
| 2026-06-15 | BERTHELSEN SPENCER R | Director | Sell | 8K | $73.49 | $588K | 156K |
| 2026-06-15 | BERTHELSEN SPENCER R | Director | Exercise or conversion | 8K | $24.42 | $195K | 164K |
| 2026-06-12 | Kordasiewicz Holly B. | EVP, Chief Development Officer | Exercise or conversion | 12K | $32.60 | $391K | 63K |
| 2026-06-12 | Kordasiewicz Holly B. | EVP, Chief Development Officer | Exercise or conversion | 21K | $60.89 | $1.3M | 51K |
| 2026-06-12 | Kordasiewicz Holly B. | EVP, Chief Development Officer | Exercise or conversion | 8K | $60.89 | $484K | 30K |
| 2026-06-12 | Kordasiewicz Holly B. | EVP, Chief Development Officer | Sell | 41K | $73.09 | $3.0M | 42K |
| 2026-06-12 | Kordasiewicz Holly B. | EVP, Chief Development Officer | Sell | 20K | $74.05 | $1.5M | 22K |
| 2026-06-12 | Kordasiewicz Holly B. | EVP, Chief Development Officer | Exercise or conversion | 20K | $56.78 | $1.1M | 83K |
| 2026-06-01 | BERTHELSEN SPENCER R | Director | Sell | 8K | $75.67 | $605K | 156K |
| 2026-06-01 | BERTHELSEN SPENCER R | Director | Exercise or conversion | 8K | $24.42 | $195K | 164K |
| 2026-05-14 | Monia Brett P | Chief Executive Officer | Sell | 3K | $78.68 | $253K | 243K |
| 2026-05-14 | Monia Brett P | Chief Executive Officer | Exercise or conversion | 3K | $32.60 | $105K | 246K |
| 2026-05-13 | Monia Brett P | Chief Executive Officer | Sell | 1K | $78.01 | $103K | 243K |
| 2026-05-13 | Monia Brett P | Chief Executive Officer | Exercise or conversion | 1K | $32.60 | $43K | 244K |
| 2026-05-04 | LOSCALZO JOSEPH | Director | Exercise or conversion | 16K | $64.80 | $1.0M | 114K |
| 2026-05-04 | LOSCALZO JOSEPH | Director | Exercise or conversion | 12K | $60.20 | $722K | 98K |
| 2026-05-04 | LOSCALZO JOSEPH | Director | Sell | 18K | $75.58 | $1.3M | 36K |
| 2026-05-04 | LOSCALZO JOSEPH | Director | Sell | 60K | $74.90 | $4.5M | 54K |
| 2026-05-04 | LOSCALZO JOSEPH | Director | Exercise or conversion | 16K | $42.88 | $686K | 86K |
| 2026-05-04 | LOSCALZO JOSEPH | Director | Exercise or conversion | 10K | $41.08 | $424K | 70K |
| 2026-05-04 | LOSCALZO JOSEPH | Director | Exercise or conversion | 12K | $40.05 | $481K | 59K |
| 2026-05-04 | LOSCALZO JOSEPH | Director | Exercise or conversion | 11K | $38.06 | $417K | 47K |
| 2026-05-01 | KLEIN JOSEPH III | Director | Sell | 1K | $74.45 | $107K | 11K |
| 2026-05-01 | KLEIN JOSEPH III | Director | Sell | 9K | $73.35 | $637K | 12K |
| 2026-05-01 | KLEIN JOSEPH III | Director | Exercise or conversion | 10K | $47.11 | $476K | 21K |
| 2026-04-28 | Baroldi Joseph | EVP, Chief Business Officer | Sell | 2K | $71.79 | $117K | 45K |
| 2026-04-16 | Jenne Kyle | EVP, Chf GL Pdt Str Ofcr | Sell | 5K | $75.17 | $368K | 24K |
| 2026-04-16 | Birchler Brian | EVP, Corp and Development Ops | Sell | 973 | $75.04 | $73K | 68K |
| 2026-04-16 | Baroldi Joseph | EVP, Chief Business Officer | Sell | 6K | $74.56 | $419K | 47K |
| 2026-04-15 | PARSHALL B LYNNE | Director | Sell | 534 | $76.97 | $41K | 51K |
| 2026-04-15 | PARSHALL B LYNNE | Director | Sell | 4K | $76.19 | $340K | 52K |
| 2026-04-15 | Jenne Kyle | EVP, Chf GL Pdt Str Ofcr | Exercise or conversion | 12K | $0.00 | $0 | 29K |
| 2026-04-15 | Birchler Brian | EVP, Corp and Development Ops | Exercise or conversion | 2K | $0.00 | $0 | 68K |
| 2026-04-15 | Baroldi Joseph | EVP, Chief Business Officer | Exercise or conversion | 11K | $0.00 | $0 | 52K |
| 2026-04-02 | Devers Shannon L. | EVP, Chief Human Resources Ofc | Sell | 6K | $74.05 | $459K | 16K |
| 2026-04-01 | KLEIN JOSEPH III | Director | Sell | 2K | $75.95 | $168K | 11K |
| 2026-04-01 | KLEIN JOSEPH III | Director | Sell | 20K | $75.50 | $1.5M | 13K |
| 2026-04-01 | KLEIN JOSEPH III | Director | Exercise or conversion | 10K | $41.08 | $424K | 33K |
| 2026-04-01 | KLEIN JOSEPH III | Director | Exercise or conversion | 12K | $38.06 | $457K | 23K |
| 2026-03-19 | Schneider Eugene | EVP, Chf Clinical Develop Ofcr | Sell | 6K | $70.97 | $412K | 64K |
| 2026-03-17 | HOUGEN ELIZABETH L | EVP, Finance & CFO | Sell | 10K | $73.21 | $745K | 83K |
| 2026-03-16 | HOUGEN ELIZABETH L | EVP, Finance & CFO | Sell | 9K | $72.77 | $687K | 93K |
| 2026-03-16 | HOUGEN ELIZABETH L | EVP, Finance & CFO | Sell | 206K | $72.38 | $14.9M | 102K |
| 2026-03-16 | HOUGEN ELIZABETH L | EVP, Finance & CFO | Exercise or conversion | 21K | $37.58 | $772K | 308K |
| 2026-03-16 | HOUGEN ELIZABETH L | EVP, Finance & CFO | Exercise or conversion | 33K | $32.60 | $1.1M | 287K |
| 2026-03-16 | HOUGEN ELIZABETH L | EVP, Finance & CFO | Exercise or conversion | 61K | $56.78 | $3.5M | 254K |
| 2026-03-16 | HOUGEN ELIZABETH L | EVP, Finance & CFO | Exercise or conversion | 60K | $60.89 | $3.7M | 193K |
| 2026-03-10 | Monia Brett P | Chief Executive Officer | Sell | 18K | $76.34 | $1.3M | 243K |
| 2026-03-10 | Monia Brett P | Chief Executive Officer | Sell | 17K | $75.47 | $1.2M | 260K |
| 2026-03-10 | Monia Brett P | Chief Executive Officer | Exercise or conversion | 34K | $60.89 | $2.1M | 277K |
| 2026-03-10 | Jenne Kyle | EVP, Chf GL Pdt Str Ofcr | Exercise or conversion | 5K | $34.69 | $162K | 16K |
| 2026-03-10 | Jenne Kyle | EVP, Chf GL Pdt Str Ofcr | Sell | 16K | $76.30 | $1.2M | 12K |
| 2026-03-10 | Jenne Kyle | EVP, Chf GL Pdt Str Ofcr | Sell | 21K | $75.50 | $1.6M | 28K |
| 2026-03-10 | Jenne Kyle | EVP, Chf GL Pdt Str Ofcr | Exercise or conversion | 33K | $46.10 | $1.5M | 49K |
| 2026-03-09 | O'NEIL PATRICK R. | EVP CLO & General Counsel | Sell | 10K | $75.25 | $764K | 62K |
| 2026-03-09 | Monia Brett P | Chief Executive Officer | Sell | 2K | $75.58 | $127K | 243K |
| 2026-03-09 | Monia Brett P | Chief Executive Officer | Sell | 118K | $75.26 | $8.9M | 244K |
| 2026-03-09 | Monia Brett P | Chief Executive Officer | Sell | 7K | $74.11 | $547K | 362K |
| 2026-03-09 | Monia Brett P | Chief Executive Officer | Exercise or conversion | 74K | $60.89 | $4.5M | 369K |
| 2026-03-09 | Monia Brett P | Chief Executive Officer | Exercise or conversion | 41K | $60.89 | $2.5M | 296K |
| 2026-03-04 | LOSCALZO JOSEPH | Director | Sell | 200 | $80.00 | $16K | 36K |
| 2026-03-04 | LOSCALZO JOSEPH | Director | Exercise or conversion | 200 | $38.06 | $8K | 37K |
| 2026-03-04 | Baroldi Joseph | EVP, Chief Business Officer | Sell | 201 | $80.00 | $16K | 4K |
| 2026-03-04 | Baroldi Joseph | EVP, Chief Business Officer | Exercise or conversion | 201 | $32.60 | $7K | 5K |
| 2026-03-04 | Baroldi Joseph | EVP, Chief Business Officer | Sell | 238 | $80.00 | $19K | 4K |
| 2026-03-04 | Baroldi Joseph | EVP, Chief Business Officer | Exercise or conversion | 238 | $56.78 | $14K | 5K |
Form 4 filings are due within two business days of the trade. Insiders sell for many reasons that say nothing about the company; open-market buys are rarer.
Planned sales (Form 144)
Newest first. JSON50 Form 144 notices on file for IONS worth $127.3M at the prices reported; 1 in the last 90 days worth $60K. Latest: Devers Shannon L. filed on 2026-10-16 to sell 1,357 shares ($60K) from 2026-10-16.
| Filed | Seller | Shares | Market value | Of outstanding | Sale from | Broker |
|---|---|---|---|---|---|---|
| 2026-10-16 | Devers Shannon L.Officer | 1K | $60K | 0.001% | 2026-10-16 | Morgan Stanley Smith Barney |
| 2026-07-07 | Kordasiewicz Holly B.Officer | 1K | $108K | 0.001% | 2026-07-07 | Stifel Nicolaus & Company Inc |
| 2026-07-07 | Diaz Allene M.Director | 10K | $864K | 0.006% | 2026-07-07 | Stifel Nicolaus & Company Inc |
| 2026-07-07 | BENNETT C FRANKOfficer | 67K | $5.7M | 0.041% | 2026-07-07 | Stifel Nicolaus & Company Inc |
| 2026-07-01 | KLEIN JOSEPH IIIDirector | 12K | $910K | 0.007% | 2026-07-01 | Stifel Nicolaus & Company Inc |
| 2026-06-26 | O'NEIL PATRICK R.Officer | 3K | $246K | 0.002% | 2026-06-26 | Stifel Nicolaus & Company Inc |
| 2026-06-26 | Schneider EugeneOfficer | 48K | $3.9M | 0.029% | 2026-06-26 | Stifel Nicolaus & Company Inc |
| 2026-06-26 | Baroldi MarianaMember of immediate family of any of the foregoing | 6K | $452K | 0.003% | 2026-06-26 | Stifel Nicolaus & Company Inc |
| 2026-06-25 | Swayze EricOfficer | 11K | $839K | 0.006% | 2026-06-25 | Stifel Nicolaus & Company Inc |
| 2026-06-15 | BERTHELSEN SPENCER RDirector | 8K | $588K | 0.005% | 2026-06-15 | Fidelity Brokerage Services LLC |
| 2026-06-12 | Kordasiewicz Holly B.Officer | 61K | $4.5M | 0.037% | 2026-06-12 | Stifel Nicolaus & Company Inc |
| 2026-06-01 | BERTHELSEN SPENCER RDirector | 8K | $605K | 0.005% | 2026-06-01 | Fidelity Brokerage Services LLC |
| 2026-05-13 | Monia Brett POfficer | 100K | $7.8M | 0.061% | 2026-05-13 | Stifel Nicolaus & Company Inc |
| 2026-05-04 | LOSCALZO JOSEPHDirector | 54K | $4.3M | 0.033% | 2026-05-04 | Stifel Nicolaus & Company Inc |
| 2026-04-28 | Baroldi JosephOfficer | 2K | $117K | 0.001% | 2026-04-28 | Stifel Nicolaus & Company Inc |
| 2026-04-16 | Jenne KyleOfficer | 5K | $370K | 0.003% | 2026-04-16 | Morgan Stanley Smith Barney |
| 2026-04-16 | Birchler BrianOfficer | 973 | $73K | 0.001% | 2026-04-16 | Morgan Stanley Smith Barney |
| 2026-04-16 | Baroldi JosephOfficer | 6K | $424K | 0.003% | 2026-04-16 | Morgan Stanley Smith Barney |
| 2026-03-31 | Diaz Allene M.Director | 69K | $5.5M | 0.042% | 2026-03-03 | Stifel Nicolaus & Company Inc |
| 2026-03-24 | Schneider EugeneOfficer | 6K | $412K | 0.004% | 2026-03-19 | Stifel Nicolaus & Company Inc |
| 2026-03-19 | Schneider EugeneOfficer | 6K | $412K | 0.004% | 2026-03-19 | Stifel Nicolaus & Company Inc |
| 2026-03-16 | HOUGEN ELIZABETH LOfficer | 225K | $16.3M | 0.141% | 2026-03-16 | Stifel Nicolaus & Company Inc |
| 2026-03-10 | Jenne KyleDirector | 58K | $4.4M | 0.035% | 2026-03-10 | Stifel Nicolaus & Company Inc |
| 2026-03-09 | O'NEIL PATRICK R.Officer | 13K | $995K | 0.008% | 2026-03-09 | Stifel Nicolaus & Company Inc |
| 2026-03-03 | BENNETT C FRANKOfficer | 85K | $7.1M | 0.053% | 2026-03-03 | Stifel Nicolaus & Company Inc |
| 2026-03-03 | LOSCALZO JOSEPHDirector | 24K | $1.9M | 0.015% | 2026-03-03 | Stifel Nicolaus & Company Inc |
| 2026-03-03 | KLEIN JOSEPH IIIDirector | 65K | $5.0M | 0.040% | 2026-03-03 | Stifel Nicolaus & Company Inc |
| 2026-03-03 | Devers Shannon L.Officer | 39K | $3.1M | 0.024% | 2026-03-03 | Stifel Nicolaus & Company Inc |
| 2026-03-03 | Baroldi MarianaOfficer | 8K | $656K | 0.005% | 2026-03-03 | Stifel Nicolaus & Company Inc |
| 2026-03-03 | Baroldi JosephOfficer | 4K | $325K | 0.003% | 2026-03-03 | Stifel Nicolaus & Company Inc |
| 2026-02-13 | Swayze EricOfficer | 16K | $1.3M | 0.010% | 2026-02-13 | Stifel Nicolaus & Company Inc |
| 2026-02-11 | PARSHALL B LYNNEDirector | 10K | $827K | 0.006% | 2026-02-11 | Stifel Nicolaus & Company Inc |
| 2026-02-06 | Monia Brett POfficer | 290K | $24.8M | 0.179% | 2026-02-06 | Stifel Nicolaus & Company Inc |
| 2026-02-02 | BENNETT C FRANKOfficer | 85K | $7.1M | 0.053% | 2026-02-02 | Stifel Nicolaus & Company Inc |
| 2026-01-30 | Monia Brett POfficer, Director | 63K | $5.2M | 0.039% | 2026-01-30 | Morgan Stanley Smith Barney |
| 2026-01-30 | O'NEIL PATRICK R.Officer | 6K | $513K | 0.004% | 2026-01-30 | Morgan Stanley Smith Barney |
| 2026-01-30 | Swayze EricOfficer | 6K | $513K | 0.004% | 2026-01-30 | Morgan Stanley Smith Barney |
| 2026-01-30 | Schneider EugeneOfficer | 6K | $513K | 0.004% | 2026-01-30 | Morgan Stanley Smith Barney |
| 2026-01-30 | HOUGEN ELIZABETH LOfficer | 7K | $580K | 0.004% | 2026-01-30 | Morgan Stanley Smith Barney |
| 2026-01-30 | Birchler BrianOfficer | 6K | $512K | 0.004% | 2026-01-30 | Morgan Stanley Smith Barney |
| 2026-01-30 | Baroldi JosephOfficer | 5K | $440K | 0.003% | 2026-01-30 | Morgan Stanley Smith Barney |
| 2026-01-30 | BENNETT C FRANKOfficer | 6K | $488K | 0.004% | 2026-01-30 | Morgan Stanley Smith Barney |
| 2026-01-23 | Devers Shannon L.Officer | 4K | $323K | 0.002% | 2026-01-22 | Stifel Nicolaus & Company Inc |
| 2026-01-22 | Devers Shannon L.Officer | 4K | $323K | 0.002% | 2026-01-22 | Stifel Nicolaus & Company Inc |
| 2026-01-21 | Baroldi MarianaMember of immediate family of any of the foregoing | 1K | $94K | 0.001% | 2026-01-16 | Morgan Stanley Smith Barney |
| 2026-01-16 | Swayze EricOfficer | 10K | $754K | 0.006% | 2026-01-16 | Morgan Stanley Smith Barney |
| 2026-01-16 | Monia Brett POfficer, Director | 44K | $3.4M | 0.027% | 2026-01-16 | Morgan Stanley Smith Barney |
| 2026-01-16 | Kordasiewicz Holly B.Officer | 4K | $315K | 0.003% | 2025-01-16 | Morgan Stanley Smith Barney |
| 2026-01-16 | O'NEIL PATRICK R.Officer | 9K | $701K | 0.006% | 2026-01-16 | Morgan Stanley Smith Barney |
| 2026-01-16 | Schneider EugeneOfficer | 9K | $709K | 0.006% | 2026-01-16 | Morgan Stanley Smith Barney |
Large holders (13D and 13G)
One row per reporting person with its latest filing, newest first. JSON2 holders report 5% or more of IONS in their latest filing, all on Schedule 13G (passive). The largest reported stake is Capital World Investors at 12.8% of the class (21,186,369 shares), filed 2026-05-14 for an event on 2026-03-31.
| Filed | Form | Holder | Shares | Of class | Event |
|---|---|---|---|---|---|
| 2026-05-15 | 13G/Ano. 5 | T. Rowe Price Investment Management, Inc.investment adviser | 6.2M | 3.7% | 2026-03-31 |
| 2026-05-14 | 13G/Ano. 2 | Capital World Investorsinvestment adviser | 21.2M | 12.8% | 2026-03-31 |
| 2026-04-30 | 13G | Vanguard Capital Managementinvestment adviser | 8.3M | 5.0% | 2026-03-31 |
| 2026-03-27 | 13G/Ano. 14 | The Vanguard Groupinvestment adviser | 0 | 0.0% | 2026-03-13 |
13F holders
Tracked managers holding IONS at their latest 13F. JSON8 of the 30 tracked managers held IONS at their latest 13F, $641.8M in total at quarter-end prices. Two Sigma Investments is the largest at $495.7M (0.4% of its portfolio) as of 2026-06-30. Over the prior quarter 3 added shares and 5 cut.
| Fund | Quarter | Shares | Value | Of portfolio | Change in shares |
|---|---|---|---|---|---|
| Two Sigma Investments | 2026-06-30 | 6.3M | $495.7M | 0.36% | +395K |
| Renaissance Technologies | 2026-06-30 | 559K | $44.4M | 0.06% | +254K |
| ARK Investment Management | 2026-06-30 | 301K | $23.8M | 0.15% | +12K |
| D. E. Shaw & Co. | 2026-06-30 | 297K | $23.6M | 0.01% | -133K |
| Millennium Management | 2026-06-30 | 289K | $22.9M | 0.01% | -763K |
| Citadel Advisors | 2026-06-30 | 236K | $18.7M | 0.00% | -706K |
| Fisher Asset Management | 2026-06-30 | 137K | $10.9M | 0.00% | -4K |
| AQR Capital Management | 2026-06-30 | 22K | $1.7M | 0.00% | -7K |
Only the 30 tracked managers on the funds hub; a 13F reports long positions in US listed stock at quarter end, 45 days late, and says nothing about shorts or positions sold since.
Financials
SEC XBRL, as filed. JSONIn Q2 FY 2026 (quarter ended 2026-06-30) Ionis Pharmaceuticals reported revenue of $267.9M, down 40.7% from the same quarter a year earlier, and net loss of $114.6M (-0.69 diluted EPS). In FY 2025 it generated -$268.6M of operating cash flow.
- Cash
- $350.1M
- Equity
- $439.7M
- Total assets
- $2.99B
- Shares outstanding
- 166,184,322
Quarterly, last 8 quarters
| Quarter | Period end | Revenue | Net income | Margin | Diluted EPS |
|---|---|---|---|---|---|
| Q2 FY 2026 | 2026-06-30 | $267.9M | -$114.6M | -42.8% | -0.69 |
| Q1 FY 2026 | 2026-03-31 | $246.1M | -$92.5M | -37.6% | -0.56 |
| Q4 FY 2025 | 2025-12-31 | $203.3M | -$229.4M | -112.8% | -1.41 |
| Q3 FY 2025 | 2025-09-30 | $156.7M | -$128.6M | -82.1% | -0.80 |
| Q2 FY 2025 | 2025-06-30 | $452.0M | $123.6M | 27.3% | 0.70 |
| Q1 FY 2025 | 2025-03-31 | $131.6M | -$146.9M | -111.6% | -0.93 |
| Q4 FY 2024 | 2024-12-31 | $226.6M | -$104.3M | -46.1% | -0.66 |
| Q3 FY 2024 | 2024-09-30 | $133.8M | -$140.5M | -105.0% | -0.95 |
Fiscal years, with buybacks and dividends
| Fiscal year | Ends | Revenue | Net income | Operating cash flow | Capex | Buybacks | Dividends |
|---|---|---|---|---|---|---|---|
| FY 2025 | 2025-12-31 | $943.7M | -$381.4M | -$268.6M | $51.4M | n/a | n/a |
| FY 2024 | 2024-12-31 | $705.1M | -$453.9M | -$500.9M | $45.3M | n/a | n/a |
| FY 2023 | 2023-12-31 | $787.6M | -$366.3M | -$307.5M | $23.8M | n/a | n/a |
| FY 2022 | 2022-12-31 | $587.4M | -$269.7M | -$274.4M | $15.7M | $0 | n/a |
| FY 2021 | 2021-12-31 | $810.5M | -$28.6M | $30.8M | $12.0M | $0 | n/a |
Quarters are the three-month figures the company reports; a fourth quarter marked derived is the fiscal year less the three reported quarters, since companies report it only inside the 10-K. Fiscal years are the annual figures. Buybacks are the cash the company paid to repurchase its common stock in the year, not the amount authorized. Balance sheet lines are as of 2026-06-30; shares outstanding as of 2026-07-23 from the cover page.
What this page is
Ionis Pharmaceuticals in the regulatory record
Regulators publish company data in separate files that never sit next to each other: FINRA's twice-monthly short interest, its daily short sale volume, the SEC's fails-to-deliver counts, and each insider's Form 4. A company page puts those series for one ticker on one URL, with planned sales, large holders, 13F holders and financials beside them, so the short position, the daily flow, the settlement fails and what insiders are doing can be read together.
Each section has its own history table, a one-line summary of the latest figures and its own JSON and CSV links, and says when its source last updated.
This page follows Ionis Pharmaceuticals (IONS), SEC CIK 874015, listed on Nasdaq, classified by the SEC as pharmaceutical preparations. The cross-market tables live on the short interest and insider transactions hubs.
Source and updates
- Short interest
- FINRA consolidated short interestSource: FINRA.Twice a month, about eight business days after settlement. Latest 2026-10-15.JSON and CSV
- Daily short volume
- FINRA Reg SHO daily filesSource: FINRA.Every trading day, the morning after FINRA posts it. Latest 2026-10-28.JSON and CSV
- Fails to deliver
- SEC fails-to-deliver dataSource: SEC.Twice a month, a few weeks after the half month ends. Latest 2026-09-10.JSON and CSV
- Planned sales
- SEC EDGAR Form 144Source: SEC.New notices appear shortly after the SEC posts them; a notice is filed on or before the sale. Latest 2026-10-16.JSON and CSV
- Large holders
- SEC EDGAR Schedule 13D and 13GSource: SEC.New filings appear shortly after the SEC posts them. A 13D is due within five business days of crossing 5%; a 13G follows the passive schedule. Latest 2026-05-15.JSON and CSV
- 13F holders
- SEC EDGAR Form 13F-HRSource: SEC.Quarterly, filed within 45 days of quarter end; 30 tracked managers. Latest 2026-06-30.JSON and CSV
- Financials
- SEC EDGAR 10-K and 10-Q filingsSource: SEC.Weekly; values are as filed in the 10-Q and 10-K. Latest 2026-06-30.JSON and CSV
- Earnings dates
- SEC EDGAR 8-K filings (Item 2.02)Source: SEC.Twice a day. Reported dates come from the company's 8-K filings; the next date is marked as an estimate until the 8-K arrives. Latest 2026-07-29.JSON and CSV
- Insider trades
- SEC EDGAR Form 4Source: SEC.New filings appear shortly after the SEC posts them; they're due two business days after the trade. Latest 2026-10-16.JSON and CSV
- Company record
- EDGAR filing index for CIK 874015Ticker, name and exchange from the SEC's company list, refreshed weekly.
- Rate limits
- 10 requests a minute without a key, 30 with a free key from a free account.
How to read it
- Read the position against the flow: rising short interest with a high daily short share is new shorting; rising short interest with a normal short share is old shorts holding on.
- Insider buys next to a large short position are rare and stand out; insider sells next to one are common and mean little.
- Fails to deliver matter relative to the float, not in absolute shares; a million failed shares in a mega cap is noise.
Analysis of what the data shows, not advice. XOOMAR does not recommend buying, selling or holding anything.
Other companies the SEC classifies as pharmaceutical preparations
Other company pages
Datasets
Frequently Asked Questions
How much of IONS is sold short?
20,653,026 shares were held short at the 2026-10-15 settlement, 7.7 days of average volume. FINRA publishes the next count about eight business days after the 15th and the last business day of the month.
What is IONS's daily short volume?
On 2026-10-28, 292,127 of the 728,501 IONS shares reported to FINRA were sold short, 40.1% of the day's reported volume. Short volume is a flow for one day, not a position.
Does IONS have fails to deliver?
The SEC's latest file shows 5,975 IONS shares failed to deliver at settlement 2026-09-10. Fails are reported per settlement date and published twice a month with a lag.
Are IONS insiders buying or selling?
Over the last 90 days IONS insiders reported 1 open-market buy ($258K) against 2 sells ($61K), so the dollar flow leans toward buying. Latest filing: Swayze Eric (EVP Research) on 2026-10-16.
Have IONS insiders filed to sell?
50 Form 144 notices on file for IONS worth $127.3M at the prices reported; 1 in the last 90 days worth $60K. Latest: Devers Shannon L. filed on 2026-10-16 to sell 1,357 shares ($60K) from 2026-10-16.
Who owns 5% or more of IONS?
2 holders report 5% or more of IONS in their latest filing, all on Schedule 13G (passive). The largest reported stake is Capital World Investors at 12.8% of the class (21,186,369 shares), filed 2026-05-14 for an event on 2026-03-31.
What did IONS report last quarter?
In Q2 FY 2026 (quarter ended 2026-06-30) Ionis Pharmaceuticals reported revenue of $267.9M, down 40.7% from the same quarter a year earlier, and net loss of $114.6M (-0.69 diluted EPS). In FY 2025 it generated -$268.6M of operating cash flow.
Which tracked 13F managers own IONS?
8 of the 30 tracked 13F managers held IONS shares at their latest filing, $641.8M in all. The largest: Two Sigma Investments (6.3M shares, $495.7M), Renaissance Technologies (559K shares, $44.4M), Cathie Wood's ARK Investment Management (301K shares, $23.8M), D. E. Shaw & Co. (297K shares, $23.6M), Izzy Englander's Millennium Management (289K shares, $22.9M), Ken Griffin's Citadel Advisors (236K shares, $18.7M). The table above lists all 8.
Data on this page is provided for informational purposes only and is not financial advice. See our editorial policy.