This company has been marked as potentially delisted and may not be actively trading. bluebird bio (BLUE) Short Interest Ratio & Short Volume Add Compare Share Share Short Interest Stock AnalysisAnalyst ForecastsFDA EventsHeadlinesInsider TradesOwnershipShort InterestTrendsBuy This Stock bluebird bio Short Interest Databluebird bio (BLUE) has a short interest of 281,500 shares, representing 2.91% of the float (the number of shares available for trading by the public). This marks a -34.26% decrease in short interest from the previous month. The short interest ratio (days to cover) is 0.5, indicating that it would take 0.5 days of the average trading volume of 452,966 shares to cover all short positions.Current Short Interest281,500 sharesPrevious Short Interest428,200 sharesChange Vs. Previous Month-34.26%Dollar Volume Sold Short$1.40 millionShort Interest Ratio0.5 Days to CoverLast Record DateMay 15, 2025Outstanding Shares9,792,000 sharesFloat Size9,690,000 sharesShort Percent of Float2.91%Today's Trading Volume0 sharesAverage Trading Volume452,966 sharesToday's Volume Vs. Average0% Short Selling bluebird bio? Sign up to receive the latest short interest report for bluebird bio and its competitors with MarketBeat's FREE newsletter. Email Address Get Report View SMS TermsBy entering your phone number and clicking the sign-up button, you agree to receive periodic text messages from MarketBeat at the phone number you submitted, including texts that may be sent using an automatic telephone dialing system. Message and data rates may apply. Message frequency will vary. Messages will consist of stock alerts, news stories, and partner advertisements/offers. Consent is not a condition of the purchase of any goods or services. Text HELP for help/customer support. 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Skip Charts & View Short Interest HistoryShort Interest ChartDays to Cover ChartShort Percent of Float ChartBLUE Short Interest Over TimeBLUE Days to Cover Over TimeBLUE Percentage of Float Shorted Over Time bluebird bio Short Interest History Export to ExcelReport DateTotal Shares Sold ShortDollar Volume Sold ShortChange from Previous ReportPercentage of Float ShortedDays to CoverPrice on Report Date 5/15/2025281,500 shares $1.40 million -34.3%2.9%0.5 $4.97 4/30/2025428,200 shares $1.75 million -15.6%4.4%1.1 $4.08 4/15/2025507,400 shares $2.27 million -71.5%5.2%1.2 $4.47 3/31/20251,780,000 shares $8.69 million -3.8%18.4%4.3 $4.88 3/15/20251,850,000 shares $6.94 million -7.0%19.2%5.2 $3.75 2/28/20251,990,000 shares $8.12 million -26.8%20.6%4.2 $4.08 2/15/20252,720,000 shares $19.77 million +7.5%28.3%5.6 $7.27 1/31/20252,530,000 shares $19.61 million +4.6%26.3%6.3 $7.75 1/15/20252,420,000 shares $20.06 million +0.4%25.1%6.1 $8.29 12/31/20242,410,000 shares $20.10 million -6.6%25.0%5.9 $8.34 Get the Latest News and Ratings for BLUE and Related StocksEnter your email address below to receive the latest news and analysts' ratings for bluebird bio and its competitors with MarketBeat's FREE daily newsletter. 12/15/20242,580,000 shares $16.36 million -94.8%26.8%6.2 $6.34 11/30/202449,570,000 shares $20.08 million +13.6%N/A6.5 $0.41 11/15/202443,640,000 shares $14.00 million -8.5%N/A6.7 $0.32 10/31/202447,710,000 shares $22.14 million -3.5%N/A6.3 $0.46 10/15/202449,420,000 shares $23.78 million +0.9%N/A6.8 $0.48 9/30/202448,990,000 shares $25.45 million +1.2%N/A6.4 $0.52 9/15/202448,400,000 shares $29.32 million -2.0%N/A6.5 $0.61 8/31/202449,370,000 shares $27.72 million +20.0%N/A6.8 $0.56 8/15/202441,140,000 shares $29.02 million +32.2%N/A6.1 $0.71 7/31/202431,130,000 shares $36.11 million +1.2%N/A5.6 $1.16 7/15/202430,770,000 shares $40.62 million +0.2%N/A5 $1.32 6/30/202430,710,000 shares $30.22 million +4.2%N/A4.9 $0.98 6/15/202429,480,000 shares $28.29 million +1.2%N/A4.7 $0.96 5/31/202429,120,000 shares $26.31 million -7.9%N/A4.5 $0.90 5/15/202431,600,000 shares $33.81 million -0.8%N/A4 $1.07 4/30/202431,860,000 shares $28.26 million -2.3%N/A3.8 $0.89 4/15/202432,620,000 shares $33.60 million +9.7%N/A3.8 $1.03 3/31/202429,750,000 shares $38.08 million -12.6%N/A3.3 $1.28 3/15/202434,040,000 shares $48.34 million -0.3%N/A3.2 $1.42 2/29/202434,130,000 shares $47.44 million +19.4%N/A2.4 $1.39 2/15/202428,590,000 shares $30.88 million +4.0%N/A2.2 $1.08 1/31/202427,500,000 shares $28.05 million +3.5%N/A2.3 $1.02 1/15/202426,570,000 shares $39.86 million +10.3%N/A2.4 $1.50 12/31/202324,090,000 shares $33.24 million -5.4%N/A2.4 $1.38 12/15/202325,470,000 shares $83.29 million +16.6%N/A2.8 $3.27 11/30/202321,850,000 shares $83.47 million -2.9%N/A4.7 $3.82 11/15/202322,490,000 shares $73.99 million -8.5%N/A6.4 $3.29 10/31/202324,570,000 shares $72.48 million -0.4%N/A7 $2.95 10/15/202324,670,000 shares $65.62 million +2.3%N/A7 $2.66 9/30/202324,110,000 shares $73.29 million -17.0%N/A5.8 $3.04 9/15/202329,040,000 shares $97.28 million +11.5%N/A7 $3.35 8/31/202326,040,000 shares $98.17 million -1.6%N/A6.3 $3.77 8/15/202326,450,000 shares $95.75 million -8.3%N/A6.2 $3.62 7/31/202328,840,000 shares $113.34 million +13.7%N/A6.6 $3.93 7/15/202325,360,000 shares $76.84 million -21.5%N/A5.8 $3.03 6/30/202332,300,000 shares $106.27 million +6.1%N/A8.1 $3.29 6/15/202330,440,000 shares $121.46 million +23.0%N/A6.8 $3.99 5/31/202324,740,000 shares $82.88 million +5.3%N/A5.2 $3.35 5/15/202323,490,000 shares $96.78 million -0.3%N/A5 $4.12 4/30/202323,550,000 shares $102.44 million -0.8%N/A5.3 $4.35 4/15/202323,740,000 shares $74.07 million -10.3%N/A5.5 $3.12 3/31/202326,450,000 shares $84.11 million +29.0%N/A6.1 $3.18 3/15/202320,510,000 shares $95.37 million +12.2%N/A5.4 $4.65 2/28/202318,280,000 shares $95.06 million +5.5%N/A5.4 $5.20 2/15/202317,320,000 shares $102.88 million +0.2%N/A5.1 $5.94 1/31/202317,290,000 shares $109.79 million -6.3%N/A4.7 $6.35 1/15/202318,450,000 shares $145.57 million +1.2%N/A4.9 $7.89 12/30/202218,240,000 shares $126.22 million -1.1%N/A5.3 $6.92 12/15/202218,450,000 shares $143.54 million +1.0%N/A4.6 $7.78 11/30/202218,270,000 shares $142.32 million -5.2%N/A3.3 $7.79 11/15/202219,270,000 shares $148.38 million -14.5%N/A3.2 $7.70 10/31/202222,540,000 shares $141.33 million +0.5%N/A3.1 $6.27 10/15/202222,440,000 shares $143.39 million -1.2%N/A2.9 $6.39 9/30/202222,710,000 shares $143.75 million +13.0%N/A2.9 $6.33 9/15/202220,100,000 shares $142.51 million +1.8%N/A2.4 $7.09 8/31/202219,740,000 shares $115.28 million +19.9%N/A2 $5.84 8/15/202216,460,000 shares $112.42 million +8.4%N/A1.8 $6.83 7/31/202215,190,000 shares $61.52 million +13.3%N/A2 $4.05 7/15/202213,410,000 shares $64.50 million -11.1%N/A2 $4.81 6/30/202215,090,000 shares $62.47 million -13.8%N/A2.3 $4.14 6/15/202217,510,000 shares $60.93 million +39.0%32.1%3.2 $3.48 5/31/202212,600,000 shares $40.32 million +1.9%N/A5.2 $3.20 5/15/202212,370,000 shares $44.16 million +1.8%N/A5.3 $3.57 4/30/202212,150,000 shares $44.10 million +6.6%N/A5.4 $3.63 4/15/202211,400,000 shares $51.76 million -0.7%N/A4.8 $4.54 3/31/202211,480,000 shares $55.68 million +43.7%N/A4.8 $4.85 3/15/20227,990,000 shares $35.72 million +9.2%N/A3.1 $4.47 2/28/20227,320,000 shares $44.21 million +2.0%N/A3.1 $6.04 2/15/20227,180,000 shares $48.68 million +3.2%N/A3.1 $6.78 1/31/20226,960,000 shares $54.91 million +1.0%N/A2.8 $7.89 1/15/20226,890,000 shares $60.15 million +19.0%N/A2.9 $8.73 12/31/20215,790,000 shares $57.84 million +4.3%N/A2.8 $9.99 12/15/20215,550,000 shares $52.78 million -3.3%N/A2.8 $9.51 11/30/20215,740,000 shares $58.03 million +6.3%N/A3.9 $10.11 11/15/20215,400,000 shares $61.99 million +5.9%N/A3.8 $11.48 10/29/20215,100,000 shares $119.39 million -11.5%7.8%3.9 $23.41 10/15/20215,760,000 shares $120.38 million -0.2%8.8%4.9 $20.90 9/30/20215,770,000 shares $110.26 million +10.5%8.8%5.1 $19.11 9/15/20215,220,000 shares $92.92 million -8.6%7.9%3.8 $17.80 8/31/20215,710,000 shares $104.49 million -9.7%8.7%4 $18.30 8/13/20216,320,000 shares $116.73 million +1.1%9.6%4.5 $18.47 7/30/20216,250,000 shares $158.81 million +6.5%9.5%4.4 $25.41 7/15/20215,870,000 shares $161.60 million -7.3%8.9%4.7 $27.53 6/30/20216,330,000 shares $202.43 million +18.3%9.6%4.8 $31.98 6/15/20215,350,000 shares $175.64 million +4.7%8.1%4.1 $32.83 5/28/20215,110,000 shares $159.02 million -13.4%7.7%3.8 $31.12 5/14/20215,900,000 shares $172.93 million -7.1%N/A3.3 $29.31 4/30/20216,350,000 shares $191.96 million -4.4%N/A2.8 $30.23 4/15/20216,640,000 shares $196.15 million -2.1%N/A2.9 $29.54 3/31/20216,780,000 shares $194.04 million +25.3%N/A2.9 $28.62 3/15/20215,410,000 shares $175.45 million -14.7%N/A2.5 $32.43 2/26/20216,340,000 shares $178.28 million +4.1%N/A3.2 $28.12 2/12/20216,090,000 shares $278.74 million +2.4%N/A3.6 $45.77 1/29/20215,950,000 shares $267.75 million -3.1%N/A4.8 $45.00 1/15/20216,140,000 shares $318.36 million -15.0%N/A5.1 $51.85 12/31/20207,220,000 shares $318.47 million +3.9%N/A6.6 $44.11 12/15/20206,950,000 shares $309.62 million +1.6%N/A7 $44.55 11/30/20206,840,000 shares $301.37 million +0.2%N/A7.4 $44.06 11/15/20206,830,000 shares $314.25 million +7.7%N/A7.9 $46.01 10/30/20206,340,000 shares $335.32 million +3.1%N/A7.8 $52.89 10/15/20206,150,000 shares $343.11 million +0.5%N/A9.1 $55.79 BLUE Short Interest - Frequently Asked Questions What is bluebird bio's current short interest? Short interest is the volume of bluebird bio shares that have been sold short but have not yet been covered or closed out. As of May 15th, traders have sold 281,500 shares of BLUE short. 2.91% of bluebird bio's shares are currently sold short. Learn More on bluebird bio's current short interest. Which institutional investors are shorting bluebird bio? As of the most recent reporting period, the following institutional investors, funds, and major shareholders have reported short positions of bluebird bio: Group One Trading LLC, Jane Street Group LLC, Equitec Proprietary Markets LLC, and FNY Investment Advisers LLC. These positions are disclosed in Form 13F filings with the Securities and Exchange Commission. What is a good short interest percentage for bluebird bio? 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. 2.91% of bluebird bio's floating shares are currently sold short. Is bluebird bio's short interest increasing or decreasing? bluebird bio saw a drop in short interest in the month of May. As of May 15th, there was short interest totaling 281,500 shares, a drop of 34.3% from the previous total of 428,200 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 bluebird bio's float size? bluebird bio currently has issued a total of 9,792,000 shares. Some of bluebird bio's 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. bluebird bio currently has a public float of 9,690,000 shares. How does bluebird bio's short interest compare to its competitors? 2.91% of bluebird bio's shares are currently sold short. Here is how the short interest of companies in the industry of "pharmaceutical products" compare to bluebird bio: BioAge Labs, Inc. (11.12%), Black Diamond Therapeutics, Inc. (12.54%), MediWound Ltd. (13.40%), China SXT Pharmaceuticals, Inc. (0.27%), FitLife Brands Inc. (0.97%), Journey Medical Corporation (14.77%), BioHarvest Sciences Inc. (0.12%), Applied Therapeutics Inc. (6.34%), GENFIT S.A. Unsponsored ADR (0.06%), Coherus Oncology, Inc. (27.42%), Which stocks are the most shorted right now? As of the most recent reporting period, the following stocks had the largest short interest positions: Invesco QQQ ($29.20 billion), Strategy Inc ($10.88 billion), iShares 20+ Year Treasury Bond ETF ($10.04 billion), Capital One Financial Corporation ($5.51 billion), Charter Communications, Inc. ($5.00 billion), Super Micro Computer, Inc. ($4.43 billion), Apollo Global Management Inc. ($4.02 billion), Hims & Hers Health, Inc. ($3.65 billion), VanEck Semiconductor ETF ($3.27 billion), and Coinbase Global, Inc. ($3.10 billion). View all of the most shorted stocks. What does it mean to sell short bluebird bio stock? Short selling BLUE is an investing strategy that aims to generate trading profit from bluebird bio as its price is falling. 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 bluebird bio? A short squeeze for bluebird bio occurs when it has a large amount of short interest and its stock increases in price. This forces short sellers to cover their short interest positions by buying actual shares of BLUE, which in turn drives the price of the stock up even further. How often is bluebird bio's 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 BLUE, twice per month. The most recent reporting period available is May, 15 2025. More Short Interest Resources from MarketBeat Related Companies BioAge Labs Short Interest Data Black Diamond Therapeutics Short Interest Data MediWound Short Interest Data China SXT Pharmaceuticals Short Interest Data Cellectis Short Interest Data FitLife Brands Short Interest Data Journey Medical Short Interest Data BioHarvest Sciences Short Interest Data Applied Therapeutics Short Interest Data GENFIT 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:BLUE) was last updated on 10/6/2025 by MarketBeat.com Staff From Our PartnersMagnificent 7 being replaced by the “Hidden 7”?BULLISH: It's time to buy this 'hidden' AI stock An award-winning stock-rating system has turned BULLISH on...Chaikin Analytics | SponsoredIs This Warren’s Buffett’s #1 AI Investment?Did you know that Warren Buffett is investing in what Jeff Brown believes will be the next generation of artif...Brownstone Research | SponsoredURGENT: The Market's 3 Red Flags Are FlashingHere’s the uncomfortable truth: The smartest investors in the world are already preparing for a crash befor...StockEarnings | SponsoredWarren Buffett’s #1 AI Stock is Not Even on the NasdaqNew Amazon Crisis Could Tank U.S. Stock Market A new panic is halting AI projects at Amazon and could split...Altimetry | SponsoredThe Fed Just Got Kneecapped — Here’s What Happens NextDonald Trump has done it again! 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