Ionis Pharmaceuticals (IONS) Short Interest Ratio & Short Volume $43.03 +0.05 (+0.12%) Closing price 08/1/2025 04:00 PM EasternExtended Trading$42.98 -0.05 (-0.10%) As of 08/1/2025 07:23 PM Eastern Extended trading is trading that happens on electronic markets outside of regular trading hours. This is a fair market value extended hours price provided by Polygon.io. Learn more. Add Compare Share Share Short Interest Stock AnalysisAnalyst ForecastsChartCompetitorsEarningsFDA EventsFinancialsHeadlinesInsider TradesOptions ChainOwnershipSEC FilingsShort InterestSustainabilityTrendsBuy This Stock Ionis Pharmaceuticals Short Interest DataIonis Pharmaceuticals (IONS) has a short interest of 12.89 million shares, representing 8.30% of the float (the number of shares available for trading by the public). This marks a -8.84% decrease in short interest from the previous month. The short interest ratio (days to cover) is 7.6, indicating that it would take 7.6 days of the average trading volume of 1.75 million shares to cover all short positions.Current Short Interest12,890,000 sharesPrevious Short Interest14,140,000 sharesChange Vs. Previous Month-8.84%Dollar Volume Sold Short$541.38 millionShort Interest Ratio7.6 Days to CoverLast Record DateJuly 15, 2025Outstanding Shares159,391,000 sharesFloat Size155,280,000 sharesShort Percent of Float8.30%Today's Trading Volume2,315,768 sharesAverage Trading Volume1,751,200 sharesToday's Volume Vs. Average132% Short Selling Ionis Pharmaceuticals? Sign up to receive the latest short interest report for Ionis Pharmaceuticals and its competitors with MarketBeat's FREE newsletter. Email Address Skip Charts & View Short Interest HistoryShort Interest ChartDays to Cover ChartShort Percent of Float ChartIONS Short Interest Over TimeIONS Days to Cover Over TimeIONS Percentage of Float Shorted Over Time Ionis Pharmaceuticals Short Interest History Export to ExcelReport DateTotal Shares Sold ShortDollar Volume Sold ShortChange from Previous ReportPercentage of Float ShortedDays to CoverPrice on Report Date 7/15/202512,890,000 shares $541.38 million -8.8%8.3%7.6 $42.00 6/30/202514,140,000 shares $558.67 million -0.6%9.1%8 $39.51 6/15/202514,230,000 shares $506.45 million -4.1%9.2%8.4 $35.59 5/31/202514,840,000 shares $499.22 million -2.8%9.6%8.9 $33.64 5/15/202515,270,000 shares $503.76 million +4.4%9.8%9.3 $32.99 4/30/202514,630,000 shares $449.29 million +0.6%9.5%8.4 $30.71 4/15/202514,550,000 shares $412.93 million +9.1%9.4%8.3 $28.38 3/31/202513,340,000 shares $402.47 million +4.1%8.6%7.7 $30.17 3/15/202512,810,000 shares $422.22 million -0.3%8.3%7.8 $32.96 2/28/202512,850,000 shares $426.49 million +1.4%8.3%7.8 $33.19 Get the Latest News and Ratings for IONS and Related StocksEnter your email address below to receive the latest news and analysts' ratings for Ionis Pharmaceuticals and its competitors with MarketBeat's FREE daily newsletter. 2/15/202512,670,000 shares $393.28 million +4.5%8.2%7.7 $31.04 1/31/202512,120,000 shares $386.63 million +18.4%7.9%7.9 $31.90 1/15/202510,240,000 shares $340.07 million -6.1%7.0%7.1 $33.21 12/31/202410,900,000 shares $381.06 million +3.5%7.5%7.8 $34.96 12/15/202410,530,000 shares $385.50 million +0.8%7.2%7.1 $36.61 11/30/202410,450,000 shares $373.38 million -5.4%7.2%6.1 $35.73 11/15/202411,050,000 shares $379.46 million +2.9%7.6%6.5 $34.34 10/31/202410,740,000 shares $412.31 million +8.8%7.4%7 $38.39 10/15/20249,870,000 shares $373.48 million -6.3%6.8%6.3 $37.84 9/30/202410,530,000 shares $421.83 million -0.8%7.2%6.6 $40.06 9/15/202410,610,000 shares $447.64 million +4.4%7.3%6.4 $42.19 8/31/202410,160,000 shares $484.43 million +2.6%7.6%6.8 $47.68 8/15/20249,900,000 shares $461.98 million +4.7%7.4%8 $46.67 7/31/20249,460,000 shares $467.89 million +1.0%7.0%7 $49.46 7/15/20249,370,000 shares $445.73 million -1.6%7.0%7.2 $47.57 6/30/20249,520,000 shares $453.72 million +10.1%7.1%7.8 $47.66 6/15/20248,650,000 shares $351.62 million +0.6%6.5%7.5 $40.65 5/31/20248,600,000 shares $323.10 million -0.4%6.4%8.3 $37.57 5/15/20248,630,000 shares $338.38 million -1.4%6.4%7.9 $39.21 4/30/20248,750,000 shares $361.03 million -8.2%6.5%8.1 $41.26 4/15/20249,530,000 shares $395.97 million +0.1%7.1%8.9 $41.55 3/31/20249,520,000 shares $412.69 million -1.6%7.1%8.2 $43.35 3/15/20249,670,000 shares $411.46 million +6.2%7.2%8.1 $42.55 2/29/20249,110,000 shares $411.86 million +0.6%6.8%7.4 $45.21 2/15/20249,060,000 shares $410.24 million +7.2%6.8%7.4 $45.28 1/31/20248,450,000 shares $434.25 million -1.1%6.0%7.5 $51.39 1/15/20248,540,000 shares $457.23 million +3.6%6.1%7.4 $53.54 12/31/20238,240,000 shares $416.86 million -3.7%5.9%7.5 $50.59 12/15/20238,560,000 shares $425.43 million -11.8%6.1%7.3 $49.70 11/30/20239,700,000 shares $479.86 million -0.4%6.9%8.7 $49.47Market Crash Warning: How to Protect Your Wealth Before August 12th (Ad)China tariffs hit August 12—and experts warn a market meltdown may follow. A free guide from American Alternative Assets reveals 3 urgent moves to protect your portfolio, plus the #1 asset class thriving during crises (hint: it’s not stocks or bonds).Get your FREE Tariff Crash Escape Plan now 11/15/20239,740,000 shares $484.76 million +0.4%7.0%9.4 $49.77 10/31/20239,700,000 shares $429.42 million +6.2%6.9%9.6 $44.27 10/15/20239,130,000 shares $438.06 million -1.8%6.5%9 $47.98 9/30/20239,300,000 shares $421.85 million -0.9%6.6%9.2 $45.36 9/15/20239,380,000 shares $402.50 million +1.0%6.7%10.1 $42.91 8/31/20239,290,000 shares $374.11 million -3.7%6.6%9.7 $40.27 8/15/20239,650,000 shares $386 million +4.8%6.9%7.9 $40.00 7/31/20239,210,000 shares $381.57 million +4.0%6.6%7.3 $41.43 7/15/20238,860,000 shares $376.37 million +2.8%6.4%7 $42.48 6/30/20238,620,000 shares $353.68 million -0.8%6.2%7.2 $41.03 6/15/20238,690,000 shares $362.29 million +33.3%6.2%7.2 $41.69 5/31/20236,520,000 shares $266.67 million -8.3%4.7%5.5 $40.90 5/15/20237,110,000 shares $257.67 million No Change5.1%7.3 $36.24 10/31/20226,860,000 shares $303.21 million -2.0%4.9%6.9 $44.20 10/15/20227,000,000 shares $324.52 million -3.5%5.0%6.9 $46.36 9/30/20227,250,000 shares $320.67 million +6.6%5.2%7.4 $44.23 9/15/20226,800,000 shares $322.93 million +9.2%4.9%7.1 $47.49 8/31/20226,230,000 shares $264.90 million -7.7%4.5%6.8 $42.52 8/15/20226,750,000 shares $299.77 million +10.7%4.8%7.2 $44.41 7/31/20226,100,000 shares $229.12 million +0.5%4.4%6 $37.56 7/15/20226,070,000 shares $238.61 million +5.9%4.3%6.1 $39.31 6/30/20225,730,000 shares $212.12 million +1.4%4.1%5.3 $37.02 6/15/20225,650,000 shares $195.89 million -5.7%4.5%5.1 $34.67 5/31/20225,990,000 shares $218.75 million -16.1%4.3%5.5 $36.52 5/15/20227,140,000 shares $257.61 million +9.2%5.1%6.6 $36.08 4/30/20226,540,000 shares $240.41 million -12.2%4.7%6.1 $36.76 4/15/20227,450,000 shares $305.23 million +3.9%5.3%6.5 $40.97 3/31/20227,170,000 shares $265.58 million -1.7%N/A0 $37.04 3/15/20227,290,000 shares $238.38 million -4.1%5.2%6.6 $32.70 2/28/20227,600,000 shares $253.69 million -18.7%5.4%6.2 $33.38 2/15/20229,350,000 shares $314.72 million -1.8%6.7%7.2 $33.66 1/31/20229,520,000 shares $302.74 million +31.9%6.8%7.7 $31.80 1/15/20227,220,000 shares $238.84 million -1.5%N/A0 $33.08 12/31/20217,330,000 shares $223.05 million -0.8%5.3%6.4 $30.43 12/15/20217,390,000 shares $229.90 million +8.2%5.3%6.6 $31.11 11/30/20216,830,000 shares $181.00 million +10.3%4.9%6.4 $26.50 11/15/20216,190,000 shares $202.97 million -10.4%4.4%6.4 $32.79 10/29/20216,910,000 shares $220.22 million +1.9%5.0%7.5 $31.87 10/15/20216,780,000 shares $237.98 million +2.1%4.9%7.4 $35.10 9/30/20216,640,000 shares $222.71 million -7.4%4.8%7.7 $33.54 9/15/20217,170,000 shares $265.00 million -6.8%5.1%7.3 $36.96 8/31/20217,690,000 shares $305.75 million -8.5%5.5%7.7 $39.76 8/13/20218,400,000 shares $333.31 million -8.6%6.0%6.4 $39.68 7/30/20219,190,000 shares $341.32 million +7.2%6.6%6.1 $37.14 7/15/20218,570,000 shares $305.69 million -4.8%6.4%5.1 $35.67 6/30/20219,000,000 shares $359.01 million +0.3%6.7%5.3 $39.89 6/15/20218,970,000 shares $329.02 million -17.3%6.7%4.9 $36.68 5/28/202110,850,000 shares $404.16 million +1.0%8.1%5.7 $37.25 5/14/202110,740,000 shares $401.35 million +4.2%8.0%6.6 $37.37 4/30/202110,310,000 shares $446.63 million +6.7%7.7%7.1 $43.32Market Crash Warning: How to Protect Your Wealth Before August 12th (Ad)China tariffs hit August 12—and experts warn a market meltdown may follow. A free guide from American Alternative Assets reveals 3 urgent moves to protect your portfolio, plus the #1 asset class thriving during crises (hint: it’s not stocks or bonds).Get your FREE Tariff Crash Escape Plan now 4/15/20219,660,000 shares $404.08 million +10.2%N/A7.5 $41.83 3/31/20218,770,000 shares $392.11 million +2.2%6.5%7.1 $44.71 3/15/20218,580,000 shares $454.65 million +0.9%6.4%7.3 $52.99 2/26/20218,500,000 shares $453.99 million +7.1%6.3%7.9 $53.41 2/12/20217,940,000 shares $460.12 million +5.2%6.0%7.4 $57.95 1/29/20217,550,000 shares $458.21 million +2.6%5.7%6.9 $60.69 1/15/20217,360,000 shares $451.54 million -5.4%5.5%6.8 $61.35 12/31/20207,780,000 shares $445.02 million +7.8%5.9%6.8 $57.20 12/15/20207,220,000 shares $345.33 million +2.1%5.4%6.1 $47.83 11/30/20207,070,000 shares $361.49 million +4.1%5.3%6.7 $51.13 11/15/20206,790,000 shares $350.16 million -5.7%5.1%6.9 $51.57 10/30/20207,200,000 shares $337.32 million -11.8%5.4%7.6 $46.85 10/15/20208,160,000 shares $389.31 million +0.1%6.2%8.9 $47.71 9/30/20208,150,000 shares $386.72 million +3.0%6.1%9.8 $47.45 9/15/20207,910,000 shares $418.68 million +4.1%6.0%10.2 $52.93 8/31/20207,600,000 shares $414.20 million -0.7%5.7%10.4 $54.50 8/14/20207,650,000 shares $403.77 million -6.0%5.8%10 $52.78 IONS Short Interest - Frequently Asked Questions What is Ionis Pharmaceuticals' current short interest? Short interest is the volume of Ionis Pharmaceuticals shares that have been sold short but have not yet been closed out or covered. As of July 15th, traders have sold 12,890,000 shares of IONS short. 8.30% of Ionis Pharmaceuticals' shares are currently sold short. Learn More on Ionis Pharmaceuticals' current short interest. What is a good short interest ratio for Ionis Pharmaceuticals? The short interest ratio, also known as the "days to cover ratio", is calculated by dividing the number of shares of a stock sold short divided by its average trading volume. A short interest ratio ranging between 1 and 4 generally indicates strong positive sentiment about a stock and a lack of short sellers. A short interest ratio of 10 or greater indicates strong pessimism about a stock. IONS shares currently have a short interest ratio of 8.0. Learn More on Ionis Pharmaceuticals's short interest ratio. Which institutional investors are shorting Ionis Pharmaceuticals? As of the most recent reporting period, the following institutional investors, funds, and major shareholders have reported short positions of Ionis Pharmaceuticals: Twin Tree Management LP, Jane Street Group LLC, Royal Bank of Canada, Caption Management LLC, Twin Tree Management LP, Torno Capital LLC, Walleye Trading LLC, Walleye Capital LLC, Simplex Trading LLC, Wolverine Asset Management LLC, Citigroup Inc., and DCF Advisers LLC. These positions are disclosed in Form 13F filings with the Securities and Exchange Commission. What is a good short interest percentage for Ionis Pharmaceuticals? Companies that have a short interest as a percentage of float below 10% indicates positive investor sentiment and few short sellers. Stocks with a short interest percentage above 10% is considered high, suggesting some investors are pessimistic about the stock. Companies with a short interest percentage of 20% or more indicates widespread negative sentiment. 8.30% of Ionis Pharmaceuticals' floating shares are currently sold short. Is Ionis Pharmaceuticals' short interest increasing or decreasing? Ionis Pharmaceuticals saw a drop in short interest in the month of July. As of July 15th, there was short interest totaling 12,890,000 shares, a drop of 8.8% from the previous total of 14,140,000 shares. Changes in short volume can be used to identify positive and negative investor sentiment. Investors that short sell a stock are betting that its price will decline in the future. An increase in short sale volume suggests bearish (negative) sentiment among investors. A decrease on short sale volume suggests bullish (positive) sentiment. What is Ionis Pharmaceuticals' float size? Ionis Pharmaceuticals currently has issued a total of 159,391,000 shares. Some of Ionis Pharmaceuticals' outstanding shares are available for trading, while others are subject to various restrictions. The public float, also referred to as floating shares or "the float", are shares that publicly owned, unrestricted and available to trade on the open market. Ionis Pharmaceuticals currently has a public float of 155,280,000 shares. How does Ionis Pharmaceuticals' short interest compare to its competitors? 8.30% of Ionis Pharmaceuticals' shares are currently sold short. Here is how the short interest of companies in the industry of "biotechnology" compare to Ionis Pharmaceuticals: Biogen Inc. (2.67%), Incyte Corporation (3.73%), United Therapeutics Corporation (3.64%), Neurocrine Biosciences, Inc. (3.26%), Exelixis, Inc. (6.92%), BioMarin Pharmaceutical Inc. (3.19%), Exact Sciences Corporation (3.96%), Halozyme Therapeutics, Inc. (7.88%), Repligen Corporation (6.40%), Madrigal Pharmaceuticals, Inc. (17.07%), Which stocks are the most shorted right now? As of the most recent reporting period, the following stocks had the largest short interest positions: Coinbase Global, Inc. ($5.11 billion), Charter Communications, Inc. ($4.76 billion), Reddit Inc. ($2.84 billion), SoFi Technologies, Inc. ($2.79 billion), Seagate Technology Holdings PLC ($2.79 billion), Live Nation Entertainment, Inc. ($2.67 billion), Rocket Lab Corporation ($2.49 billion), AST SpaceMobile, Inc. ($2.12 billion), Moderna, Inc. ($2.09 billion), and Omnicom Group Inc. ($2.04 billion). View all of the most shorted stocks. What does it mean to sell short Ionis Pharmaceuticals stock? Short selling IONS is an investing strategy that aims to generate trading profit from Ionis Pharmaceuticals as its price is falling. IONS shares are trading up $0.05 today. To short a stock, an investor borrows shares, sells them and buys the shares back on the public market later to return it to the lender. Short sellers are betting that a stock will decline in price. If the stock does drop after selling, the short seller buys it back at a lower price and returns it to the lender. The difference between the sell price and the buy price is the trader's profit. How does a short squeeze work against Ionis Pharmaceuticals? A short squeeze for Ionis Pharmaceuticals occurs when it has a large amount of short interest and its stock appreciates in price. This forces short sellers to cover their short interest positions by buying actual shares of IONS, which in turn drives the price of the stock up even further. How often is Ionis Pharmaceuticals' short interest reported? Short interest is typically published by a stock exchange once per month. However, NASDAQ publishes a report for U.S. stocks, including IONS, twice per month. The most recent reporting period available is July, 15 2025. More Short Interest Resources from MarketBeat Related Companies BIIB Short Interest INCY Short Interest UTHR Short Interest NBIX Short Interest EXEL Short Interest BMRN Short Interest EXAS Short Interest HALO Short Interest RGEN Short Interest MDGL Short Interest Short Interest Tools Stocks to Short Largest Short Interest Positions Short Interest Increases Short Interest Decreases Short Interest Reporting Dates This page (NASDAQ:IONS) was last updated on 8/2/2025 by MarketBeat.com Staff From Our PartnersElon’s Secret Social Security BombshellTo All Americans Born Before April 16th, 1963: Did Trump Just Give The Green Light To Radically RE-DO Social S...Banyan Hill Publishing | SponsoredElon’s BIGGEST warning yet?Tesla's About to Prove Everyone Wrong... Again Back in 2018, when Jeff Brown told everyone to buy Tesla… ...Brownstone Research | SponsoredChina just unlocked Nvidia’s AI chips—what that means for youTired of Missing Big AI Moves Like Nvidia? 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