Cerus (CERS) Short Interest Ratio & Short Volume $1.42 -0.02 (-1.39%) Closing price 04:00 PM EasternExtended Trading$1.44 +0.02 (+1.41%) As of 07:55 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 ForecastsChartCompetitorsEarningsHeadlinesInsider TradesOptions ChainOwnershipSEC FilingsShort InterestTrendsBuy This Stock Cerus Short Interest DataCerus (CERS) has a short interest of 9.04 million shares, representing 5.04% of the float (the number of shares available for trading by the public). This marks a 2.26% increase in short interest from the previous month. The short interest ratio (days to cover) is 6.6, indicating that it would take 6.6 days of the average trading volume of 1.31 million shares to cover all short positions.Current Short Interest9,040,000 sharesPrevious Short Interest8,840,000 sharesChange Vs. Previous Month+2.26%Dollar Volume Sold Short$11.21 millionShort Interest Ratio6.6 Days to CoverLast Record DateMay 31, 2025Outstanding Shares191,160,000 sharesShort Percent of Float5.04%Today's Trading Volume659,351 sharesAverage Trading Volume1,306,924 sharesToday's Volume Vs. Average50% Short Selling Cerus? Sign up to receive the latest short interest report for Cerus and its competitors with MarketBeat's FREE newsletter. Email Address Skip Charts & View Short Interest HistoryShort Interest ChartDays to Cover ChartShort Percent of Float ChartCERS Short Interest Over TimeCERS Days to Cover Over TimeCERS Percentage of Float Shorted Over Time Cerus Short Interest History Export to ExcelReport DateTotal Shares Sold ShortDollar Volume Sold ShortChange from Previous ReportPercentage of Float ShortedDays to CoverPrice on Report Date 5/31/20259,040,000 shares $11.21 million +2.3%5.0%6.6 $1.24 5/15/20258,840,000 shares $11.40 million -5.9%4.9%6.9 $1.29 4/30/20259,390,000 shares $12.39 million -10.5%N/A7.2 $1.32 4/15/202510,490,000 shares $13.95 million +6.1%5.8%7.1 $1.33 3/31/20259,890,000 shares $13.75 million -3.4%5.5%6.5 $1.39 3/15/202510,240,000 shares $14.85 million +1.5%5.7%6.7 $1.45 2/28/202510,090,000 shares $16.65 million +8.4%5.6%7.1 $1.65 2/15/20259,310,000 shares $17.22 million +8.3%5.2%6.9 $1.85 1/31/20258,600,000 shares $16.08 million -1.4%N/A6.1 $1.87 1/15/20258,720,000 shares $16.13 million +11.8%N/A5.6 $1.85 Get the Latest News and Ratings for CERS and Related StocksEnter your email address below to receive the latest news and analysts' ratings for Cerus and its competitors with MarketBeat's FREE daily newsletter. 12/31/20247,800,000 shares $12.01 million +16.2%N/A4.9 $1.54 12/15/20246,710,000 shares $11.47 million +1.4%N/A4.4 $1.71 11/30/20246,620,000 shares $12.25 million -4.3%N/A4.4 $1.85 11/15/20246,920,000 shares $11.90 million -12.7%N/A4.8 $1.72 10/31/20247,930,000 shares $12.45 million +7.9%N/A5.7 $1.57 10/15/20247,350,000 shares $13.23 million +4.4%N/A6.4 $1.80 9/30/20247,040,000 shares $12.25 million +6.2%N/A7 $1.74 9/15/20246,630,000 shares $13.72 million +3.4%N/A7.1 $2.07 8/31/20246,410,000 shares $14.49 million +0.5%N/A7.1 $2.26 8/15/20246,380,000 shares $13.97 million -0.6%N/A6.9 $2.19 7/31/20246,420,000 shares $14.51 million -6.0%N/A6.6 $2.26 7/15/20246,830,000 shares $15.37 million -4.3%N/A7.1 $2.25 6/30/20247,140,000 shares $12.57 million +7.7%N/A7.9 $1.76 6/15/20246,630,000 shares $11.54 million +3.3%N/A6.9 $1.74 5/31/20246,420,000 shares $11.49 million +6.8%N/A4.5 $1.79 5/15/20246,010,000 shares $12.20 million +5.1%N/A3.9 $2.03 4/30/20245,720,000 shares $9.55 million -3.4%N/A3.6 $1.67 4/15/20245,920,000 shares $10.24 million +0.7%N/A3.7 $1.73 3/31/20245,880,000 shares $11.11 million +16.0%N/A3.6 $1.89 3/15/20245,070,000 shares $9.68 million +12.7%N/A3.1 $1.91 2/29/20244,500,000 shares $9.81 million +4.2%N/A3.3 $2.18 2/15/20244,320,000 shares $10.32 million -3.6%N/A3.1 $2.39 1/31/20244,480,000 shares $8.11 million +5.9%N/A3.2 $1.81 1/15/20244,230,000 shares $7.17 million -8.0%N/A3.1 $1.70 12/31/20234,600,000 shares $9.94 million -13.2%N/A3.4 $2.16 12/15/20235,300,000 shares $11.34 million -5.0%N/A4 $2.14 11/30/20235,580,000 shares $8.98 million -7.8%N/A4.6 $1.61 11/15/20236,050,000 shares $10.47 million -3.0%N/A5.6 $1.73 10/31/20236,240,000 shares $8.74 million +11.6%N/A5.8 $1.40 10/15/20235,590,000 shares $7.21 million -4.0%N/A5.1 $1.29Trump’s treachery (Ad)Trump’s Final Reset Inside the shocking plot to re-engineer America’s financial system…and why you need to move your money now.Millions of Americans are about to be wiped out, while others could make a fortune… click here to ma 9/30/20235,820,000 shares $9.43 million +8.6%N/A5.2 $1.62 9/15/20235,360,000 shares $8.74 million -4.1%N/A4.7 $1.63 8/31/20235,590,000 shares $10.57 million -4.4%N/A4.7 $1.89 8/15/20235,850,000 shares $10.82 million +7.7%N/A4.6 $1.85 7/31/20235,430,000 shares $16.67 million -1.8%N/A4 $3.07 7/15/20235,530,000 shares $13.38 million -9.1%N/A4.3 $2.42 6/30/20236,080,000 shares $14.96 million -0.7%N/A4.8 $2.46 6/15/20236,120,000 shares $16.34 million -4.8%N/A4.8 $2.67 5/31/20236,430,000 shares $13.76 million -11.9%N/A4.7 $2.14 5/15/20237,300,000 shares $13.58 million -0.1%N/A5 $1.86 4/30/20237,310,000 shares $16.89 million -7.9%N/A5.3 $2.31 4/15/20237,940,000 shares $22.31 million -5.6%4.7%5.5 $2.81 3/31/20238,410,000 shares $24.98 million -5.2%5.0%5.1 $2.97 3/15/20238,870,000 shares $25.72 million +15.5%5.2%5.4 $2.90 2/28/20237,680,000 shares $21.96 million +17.4%N/A5.1 $2.86 2/15/20236,540,000 shares $19.75 million +4.5%N/A4.8 $3.02 1/31/20236,260,000 shares $19.66 million -0.3%N/A4.7 $3.14 1/15/20236,280,000 shares $19.72 million +11.7%N/A4.8 $3.14 12/30/20225,620,000 shares $20.51 million +0.2%N/A4.5 $3.65 12/15/20225,610,000 shares $23.06 million -9.8%N/A4.8 $4.11 11/30/20226,220,000 shares $24.88 million +0.2%N/A5.1 $4.00 11/15/20226,210,000 shares $25.09 million -6.5%N/A4.8 $4.04 10/31/20226,640,000 shares $24.30 million -6.9%N/A4.6 $3.66 10/15/20227,130,000 shares $24.53 million -5.9%4.2%4.9 $3.44 9/30/20227,580,000 shares $27.29 million +10.0%4.4%4.9 $3.60 9/15/20226,890,000 shares $27.63 million -2.3%4.0%4.3 $4.01 8/31/20227,050,000 shares $28.98 million +20.5%4.1%4.3 $4.11 8/15/20225,850,000 shares $30.01 million No Change3.4%3.4 $5.13 7/31/20225,850,000 shares $31.59 million -12.7%3.4%2.9 $5.40 7/15/20226,700,000 shares $38.06 million -5.1%3.9%3.1 $5.68 6/30/20227,060,000 shares $37.35 million -9.7%4.1%3.3 $5.29 6/15/20227,820,000 shares $36.91 million +7.9%4.6%3.8 $4.72 5/31/20227,250,000 shares $35.89 million -5.2%4.2%3.6 $4.95 5/15/20227,650,000 shares $40.39 million -13.5%4.5%3.9 $5.28 4/30/20228,840,000 shares $40.84 million +5.1%N/A5.5 $4.62 4/15/20228,410,000 shares $40.62 million +3.1%5.0%5.5 $4.83 3/31/20228,160,000 shares $44.80 million -3.1%4.9%5.1 $5.49 3/15/20228,420,000 shares $40.84 million -3.6%5.0%5.2 $4.85 2/28/20228,730,000 shares $51.25 million -2.0%5.2%5.2 $5.87 2/15/20228,910,000 shares $49.09 million +4.0%5.3%5.4 $5.51 1/31/20228,570,000 shares $45.94 million +5.0%5.1%5.4 $5.36 1/15/20228,160,000 shares $47.65 million -3.8%4.9%5.2 $5.84 12/31/20218,480,000 shares $57.75 million -6.5%5.1%6.2 $6.81 12/15/20219,070,000 shares $59.05 million +1.6%5.4%6.9 $6.51 11/30/20218,930,000 shares $61.53 million -4.6%5.3%7.8 $6.89 11/15/20219,360,000 shares $66.74 million -19.1%5.6%8.5 $7.13 10/29/202111,570,000 shares $76.36 million +6.8%6.9%10.7 $6.60 10/15/202110,830,000 shares $66.28 million +2.3%6.5%9.5 $6.12 9/30/202110,590,000 shares $64.49 million -5.5%6.4%8.4 $6.09 9/15/202111,200,000 shares $69.33 million -3.0%6.7%8.2 $6.19The Trump Dump is starting; Get out of stocks now? (Ad)The first 365 days of the Trump presidency… Will be the best time to get rich in American history.If I’m right about this (like I was before) a modest $900 investment could grow to a life-changing a 8/31/202111,540,000 shares $74.43 million -22.5%6.9%7.9 $6.45 8/13/202114,890,000 shares $89.49 million +16.7%8.9%9.4 $6.01 7/30/202112,760,000 shares $64.31 million -1.3%7.7%7.3 $5.04 7/15/202112,930,000 shares $61.93 million -1.5%7.8%7.6 $4.79 6/30/202113,130,000 shares $77.60 million -16.9%7.9%7.6 $5.91 6/15/202115,800,000 shares $91.64 million +14.9%9.5%8.7 $5.80 5/28/202113,750,000 shares $79.61 million +0.2%8.3%7.2 $5.79 5/14/202113,730,000 shares $76.20 million +8.8%N/A6 $5.55 4/30/202112,620,000 shares $75.47 million -1.3%N/A5.5 $5.98 4/15/202112,790,000 shares $79.55 million -13.4%N/A5.8 $6.22 3/31/202114,770,000 shares $85.96 million +6.8%N/A6.5 $5.82 3/15/202113,830,000 shares $88.37 million +50.0%N/A6 $6.39 2/26/20219,220,000 shares $59.47 million +0.4%N/A4 $6.45 2/12/20219,180,000 shares $68.85 million +0.9%N/A4.5 $7.50 1/29/20219,100,000 shares $61.20 million +5.8%N/A4.5 $6.73 1/15/20218,600,000 shares $64.93 million +1.7%N/A4.4 $7.55 12/31/20208,460,000 shares $60.66 million -19.5%N/A4.4 $7.17 12/15/202010,510,000 shares $74.94 million +2.8%N/A5.7 $7.13 11/30/202010,220,000 shares $67.25 million +7.2%N/A6.9 $6.58 11/15/20209,530,000 shares $57.94 million -9.2%N/A6.6 $6.08 10/30/202010,490,000 shares $58.27 million +5.6%N/A7.4 $5.56 10/15/20209,930,000 shares $66.93 million -7.5%N/A6.8 $6.74 9/30/202010,740,000 shares $67.23 million -1.8%N/A7.1 $6.26 9/15/202010,940,000 shares $70.13 million -4.3%N/A6.7 $6.41 8/31/202011,430,000 shares $72.81 million +15.2%N/A6 $6.37 8/14/20209,920,000 shares $69.34 million +0.3%N/A5.1 $6.99 7/31/20209,890,000 shares $70.52 million -6.9%N/A5 $7.13 7/15/202010,620,000 shares $72.32 million +1.2%N/A5.3 $6.81 6/30/202010,490,000 shares $69.23 million +16.0%N/A5.2 $6.60 6/15/20209,040,000 shares $56.95 million +9.3%N/A4.6 $6.30 CERS Short Interest - Frequently Asked Questions What is Cerus' current short interest? Short interest is the volume of Cerus shares that have been sold short but have not yet been closed out or covered. As of May 31st, traders have sold 9,040,000 shares of CERS short. 5.04% of Cerus' shares are currently sold short. Learn More on Cerus' current short interest. What is a good short interest ratio for Cerus? 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. CERS shares currently have a short interest ratio of 7.0. Learn More on Cerus's short interest ratio. Which institutional investors are shorting Cerus? As of the most recent reporting period, the following institutional investors, funds, and major shareholders have reported short positions of Cerus: Simplex Trading LLC. These positions are disclosed in Form 13F filings with the Securities and Exchange Commission. What is a good short interest percentage for Cerus? 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. 5.04% of Cerus' floating shares are currently sold short. Is Cerus' short interest increasing or decreasing? Cerus saw a increase in short interest in May. As of May 31st, there was short interest totaling 9,040,000 shares, an increase of 2.3% from the previous total of 8,840,000 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. How does Cerus' short interest compare to its competitors? 5.04% of Cerus' shares are currently sold short. Here is how the short interest of companies in the sector of "medical" compare to Cerus: STAAR Surgical (11.46%), OraSure Technologies, Inc. (3.53%), Utah Medical Products, Inc. (3.07%), Anika Therapeutics, Inc. (3.00%), West Pharmaceutical Services, Inc. (2.98%), The Cooper Companies, Inc. (2.58%), Align Technology, Inc. (4.49%), Merit Medical Systems, Inc. (6.08%), Haemonetics Co. (8.70%), ICU Medical, Inc. (4.68%), Which stocks are the most shorted right now? As of the most recent reporting period, the following stocks had the largest short interest positions: SPDR S&P 500 ETF Trust ($64.96 billion), Invesco QQQ ($27.88 billion), iShares Russell 2000 ETF ($19.94 billion), iShares 20+ Year Treasury Bond ETF ($9.69 billion), Strategy Incorporated ($8.58 billion), SPDR S&P Biotech ETF ($5.72 billion), Invesco S&P 500 Equal Weight ETF ($5.45 billion), iShares iBoxx $ Investment Grade Corporate Bond ETF ($4.70 billion), Charter Communications, Inc. ($4.54 billion), and Industrial Select Sector SPDR Fund ($4.49 billion). View all of the most shorted stocks. What does it mean to sell short Cerus stock? Short selling CERS is an investing strategy that aims to generate trading profit from Cerus as its price is falling. CERS shares are trading down $0.02 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 Cerus? A short squeeze for Cerus 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 CERS, which in turn drives the price of the stock up even further. How often is Cerus' 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 CERS, twice per month. The most recent reporting period available is May, 31 2025. More Short Interest Resources from MarketBeat Related Companies STAAR Surgical Short Interest Data OraSure Technologies Short Interest Data Utah Medical Products Short Interest Data Anika Therapeutics Short Interest Data West Pharmaceutical Services Short Interest Data Cooper Companies Short Interest Data Align Technology Short Interest Data Merit Medical Systems Short Interest Data Haemonetics Short Interest Data ICU Medical Short Interest Data Short Interest Tools Stocks to Short Largest Short Interest Positions Short Interest Increases Short Interest Decreases Short Interest Reporting Dates This page (NASDAQ:CERS) was last updated on 6/11/2025 by MarketBeat.com Staff From Our PartnersUtah’s New Oil FindThe Real Reason 218,000 Acres Just Vanished The government just quietly leased 218,000 acres in the middle ...Stansberry Research | SponsoredTrump wipes out trillions overnight…Is there anybody more powerful than Donald Trump right now? 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