Masimo (MASI) Short Interest Ratio & Short Volume $167.67 -3.67 (-2.14%) Closing price 07/3/2025 03:51 PM EasternExtended Trading$167.67 0.00 (0.00%) As of 07/3/2025 04:06 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 ForecastsChartCompetitorsEarningsFinancialsHeadlinesInsider TradesOptions ChainOwnershipSEC FilingsShort InterestSustainabilityTrendsBuy This Stock Masimo Short Interest DataMasimo (MASI) has a short interest of 3.28 million shares, representing 6.57% of the float (the number of shares available for trading by the public). This marks a 4.79% increase in short interest from the previous month. The short interest ratio (days to cover) is 5.1, indicating that it would take 5.1 days of the average trading volume of 639,289 shares to cover all short positions.Current Short Interest3,280,000 sharesPrevious Short Interest3,130,000 sharesChange Vs. Previous Month+4.79%Dollar Volume Sold Short$528.74 millionShort Interest Ratio5.1 Days to CoverLast Record DateJune 15, 2025Outstanding Shares54,220,000 sharesFloat Size49,950,000 sharesShort Percent of Float6.57%Today's Trading Volume498,674 sharesAverage Trading Volume639,289 sharesToday's Volume Vs. Average78% Short Selling Masimo? Sign up to receive the latest short interest report for Masimo and its competitors with MarketBeat's FREE newsletter. Email Address Skip Charts & View Short Interest HistoryShort Interest ChartDays to Cover ChartShort Percent of Float ChartMASI Short Interest Over TimeMASI Days to Cover Over TimeMASI Percentage of Float Shorted Over Time Masimo Short Interest History Export to ExcelReport DateTotal Shares Sold ShortDollar Volume Sold ShortChange from Previous ReportPercentage of Float ShortedDays to CoverPrice on Report Date 6/15/20253,280,000 shares $528.74 million +4.8%6.6%5.1 $161.20 5/31/20253,130,000 shares $505.06 million +3.3%6.3%4.7 $161.36 5/15/20253,030,000 shares $467.80 million +17.4%6.1%4.6 $154.39 4/30/20252,580,000 shares $415.28 million -7.5%5.2%4.1 $160.96 4/15/20252,790,000 shares $424.25 million -3.8%5.6%4.8 $152.06 3/31/20252,900,000 shares $483.14 million -13.4%5.8%4.9 $166.60 3/15/20253,350,000 shares $563.50 million -0.6%6.8%6.2 $168.21 2/28/20253,370,000 shares $636.15 million +12.0%6.8%6.5 $188.77 2/15/20253,010,000 shares $545.74 million +3.4%6.1%6 $181.31 1/31/20252,910,000 shares $507.01 million +3.2%5.9%5.6 $174.23 Get the Latest News and Ratings for MASI and Related StocksEnter your email address below to receive the latest news and analysts' ratings for Masimo and its competitors with MarketBeat's FREE daily newsletter. 1/15/20252,820,000 shares $485.24 million +2.9%5.7%5.2 $172.07 12/31/20242,740,000 shares $452.92 million -20.6%5.6%4.9 $165.30 12/15/20243,450,000 shares $607.68 million +7.8%7.0%5.2 $176.14 11/30/20243,200,000 shares $552.13 million -4.2%6.5%4.5 $172.54 11/15/20243,340,000 shares $537.97 million -0.3%6.8%4.7 $161.07 10/31/20243,350,000 shares $482.43 million -6.4%6.8%4.9 $144.01 10/15/20243,580,000 shares $515.27 million +3.2%7.3%4.7 $143.93 9/30/20243,470,000 shares $462.66 million +18.8%7.1%4.5 $133.33 9/15/20242,920,000 shares $329.38 million -25.7%5.9%4.2 $112.80 8/31/20243,930,000 shares $461.85 million -41.8%8.0%5.9 $117.52 8/15/20246,750,000 shares $820.60 million +43.3%13.7%9.1 $121.57 7/31/20244,710,000 shares $503.88 million +82.6%9.6%5.6 $106.98 7/15/20242,580,000 shares $280.91 million -3.4%5.3%3.6 $108.88 6/30/20242,670,000 shares $336.26 million -58.9%5.4%4 $125.94 6/15/20246,500,000 shares $881.99 million +33.2%13.2%9.6 $135.69 5/31/20244,880,000 shares $607.56 million +58.4%10.0%7.6 $124.50 5/15/20243,080,000 shares $357.74 million -20.8%6.3%5 $116.15 4/30/20243,890,000 shares $522.85 million -3.7%8.0%7.1 $134.41 4/15/20244,040,000 shares $557.96 million -4.5%8.3%7.7 $138.11 3/31/20244,230,000 shares $621.18 million -9.0%8.7%7 $146.85 3/15/20244,650,000 shares $616.96 million -2.1%9.5%7.4 $132.68 2/29/20244,750,000 shares $610.57 million -7.1%9.7%7 $128.54 2/15/20245,110,000 shares $685.46 million +3.4%10.5%7.1 $134.14 1/31/20244,940,000 shares $636.96 million +8.3%10.0%6 $128.94 1/15/20244,560,000 shares $539.54 million +4.1%9.3%5 $118.32 12/31/20234,380,000 shares $513.38 million -1.6%8.9%4.8 $117.21 12/15/20234,450,000 shares $497.02 million -1.1%9.0%4.5 $111.69 11/30/20234,500,000 shares $421.92 million +8.4%9.1%4.4 $93.76 11/15/20234,150,000 shares $378.27 million +7.0%8.4%4.1 $91.15 10/31/20233,880,000 shares $314.78 million -2.8%7.9%3.9 $81.13Is Elon's empire crumbling? 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Click here to see the Tesla shock that could blindside everyone. 10/15/20233,990,000 shares $308.63 million No Change8.1%4.1 $77.35 9/30/20233,990,000 shares $349.84 million +2.1%8.1%3.7 $87.68 9/15/20233,910,000 shares $395.38 million +11.4%7.9%3.9 $101.12 8/31/20233,510,000 shares $401.12 million -4.6%7.1%4 $114.28 8/15/20233,680,000 shares $407.71 million +6.7%7.5%4.5 $110.79 7/31/20233,450,000 shares $421.94 million +34.8%7.0%4.4 $122.30 7/15/20232,560,000 shares $382.90 million +0.4%5.2%3.9 $149.57 6/30/20232,550,000 shares $419.60 million +2.4%5.2%5.8 $164.55 6/15/20232,490,000 shares $406.54 million +32.5%5.1%6.1 $163.27 5/31/20231,880,000 shares $304.26 million +75.7%3.8%4.8 $161.84 5/15/20231,070,000 shares $185.43 million +23.6%2.2%2.9 $173.30 4/30/2023865,600 shares $163.72 million +1.3%1.8%2.8 $189.14 4/15/2023854,700 shares $163.82 million +16.4%1.8%2.8 $191.67 3/31/2023734,200 shares $135.49 million -17.9%1.5%2.2 $184.54 3/15/2023894,000 shares $154.79 million +0.7%1.9%2.5 $173.14 2/28/2023887,500 shares $148.49 million -6.6%1.8%2.2 $167.31 2/15/2023950,500 shares $159.54 million -15.9%2.0%2.3 $167.85 1/31/20231,130,000 shares $192.19 million -22.6%2.3%2.2 $170.08 1/15/20231,460,000 shares $228.86 million -5.2%3.0%2.5 $156.75 12/30/20221,540,000 shares $227.84 million -21.0%3.2%2.5 $147.95 12/15/20221,950,000 shares $281.40 million -13.0%4.0%3 $144.31 11/30/20222,240,000 shares $324.67 million -14.8%4.6%3.2 $144.94 11/15/20222,630,000 shares $332.91 million -9.6%5.4%3.5 $126.58 10/31/20222,910,000 shares $382.96 million -5.5%6.0%3.3 $131.60 10/15/20223,080,000 shares $407.58 million -10.2%6.4%3.3 $132.33 9/30/20223,430,000 shares $484.18 million +4.3%7.1%3.7 $141.16 9/15/20223,290,000 shares $510.77 million -4.6%6.8%3.6 $155.25 8/31/20223,450,000 shares $506.77 million -15.9%7.2%3.9 $146.89 8/15/20224,100,000 shares $655.06 million +16.2%8.5%4.7 $159.77 7/31/20223,530,000 shares $510.37 million +22.2%7.2%4.1 $144.58 7/15/20222,890,000 shares $369.49 million +7.0%5.9%3.3 $127.85 6/30/20222,700,000 shares $352.81 million -2.9%5.5%3.2 $130.67 6/15/20222,780,000 shares $351.75 million -18.0%5.7%2.9 $126.53 5/31/20223,390,000 shares $476.06 million +1.5%6.6%3.4 $140.43 5/15/20223,340,000 shares $454.37 million +44.0%6.5%3.1 $136.04 4/30/20222,320,000 shares $262.09 million +5.5%4.5%2.1 $112.97 4/15/20222,200,000 shares $296.71 million +46.7%4.3%2.2 $134.87 3/31/20221,500,000 shares $218.31 million +63.8%2.9%1.6 $145.54 3/15/2022915,800 shares $127.06 million +25.8%1.8%1.1 $138.74 2/28/2022728,100 shares $114.64 million -45.7%1.4%1 $157.45 2/15/20221,340,000 shares $306.65 million +1.5%2.6%2.3 $228.84 1/31/20221,320,000 shares $290.23 million -15.4%2.6%4.2 $219.87 1/15/20221,560,000 shares $363.60 million +16.4%3.1%5.6 $233.08 12/31/20211,340,000 shares $392.33 million -9.5%2.6%5.4 $292.78 12/15/20211,480,000 shares $420.13 million -6.3%2.9%6 $283.87 11/30/20211,580,000 shares $439.43 million -2.5%3.1%6.6 $278.12 11/15/20211,620,000 shares $484.02 million +10.2%3.2%6.7 $298.78 10/29/20211,470,000 shares $416.80 million -7.0%2.9%6.4 $283.54 10/15/20211,580,000 shares $452.07 million -1.9%3.1%7 $286.12 9/30/20211,610,000 shares $435.84 million +12.6%3.2%6.9 $270.71Is Elon's empire crumbling? 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Click here to see the Tesla shock that could blindside everyone. 9/15/20211,430,000 shares $390.02 million -8.9%2.8%5.6 $272.74 8/31/20211,570,000 shares $426.32 million -4.3%3.1%5.6 $271.54 8/13/20211,640,000 shares $433.32 million No Change3.2%5.4 $264.22 7/30/20211,640,000 shares $446.72 million +9.3%3.2%5 $272.39 7/15/20211,500,000 shares $399 million +11.1%3.0%4.2 $266.00 6/30/20211,350,000 shares $327.31 million +8.0%2.7%3.9 $242.45 6/15/20211,250,000 shares $280.74 million -3.1%2.5%3.7 $224.59 5/28/20211,290,000 shares $278.12 million +5.7%2.6%3.8 $215.60 5/14/20211,220,000 shares $267.33 million +31.4%2.4%3.6 $219.12 4/30/2021928,800 shares $216.80 million +19.4%1.8%2.7 $233.42 4/15/2021778,000 shares $186.37 million -12.0%1.5%2.4 $239.55 3/31/2021884,000 shares $199.90 million -8.6%1.7%2.6 $226.13 3/15/2021966,700 shares $222.73 million -0.3%1.9%2.9 $230.40 2/26/2021969,600 shares $238.63 million +9.8%1.9%3.1 $246.11 2/12/2021883,100 shares $239.13 million -0.7%1.7%2.8 $270.79 1/29/2021889,700 shares $229.16 million -13.6%1.8%2.7 $257.57 1/15/20211,030,000 shares $269.61 million -3.7%2.0%3.2 $261.76 12/31/20201,070,000 shares $286.25 million -2.7%2.1%3.4 $267.52 12/15/20201,100,000 shares $289.30 million -14.1%2.2%3.2 $263.00 11/30/20201,280,000 shares $325.64 million +7.6%2.5%3.5 $254.41 11/15/20201,190,000 shares $292.19 million -4.0%2.3%3.3 $245.54 10/30/20201,240,000 shares $279.84 million -6.8%2.4%3.4 $225.68 10/15/20201,330,000 shares $308.41 million -2.2%2.6%3.4 $231.89 9/30/20201,360,000 shares $321.04 million +10.6%2.7%3.2 $236.06 9/15/20201,230,000 shares $274.77 million -0.8%2.4%2.8 $223.39 8/31/20201,240,000 shares $277.76 million -1.6%2.4%2.6 $224.00 8/14/20201,260,000 shares $269.75 million +6.8%2.5%2.2 $214.09 7/31/20201,180,000 shares $259.74 million +27.5%2.3%1.9 $220.12 7/15/2020925,800 shares $207.70 million -31.4%1.9%1.4 $224.35 MASI Short Interest - Frequently Asked Questions What is Masimo's current short interest? Short interest is the volume of Masimo shares that have been sold short but have not yet been closed out or covered. As of June 15th, investors have sold 3,280,000 shares of MASI short. 6.57% of Masimo's shares are currently sold short. Learn More on Masimo's current short interest. What is a good short interest ratio for Masimo? 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. MASI shares currently have a short interest ratio of 5.0. Learn More on Masimo's short interest ratio. Which institutional investors are shorting Masimo? As of the most recent reporting period, the following institutional investors, funds, and major shareholders have reported short positions of Masimo: Millennium Management LLC, PEAK6 LLC, Walleye Capital LLC, and 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 Masimo? 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. 6.57% of Masimo's floating shares are currently sold short. Is Masimo's short interest increasing or decreasing? Masimo saw a increase in short interest in the month of June. As of June 15th, there was short interest totaling 3,280,000 shares, an increase of 4.8% from the previous total of 3,130,000 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 Masimo's float size? Masimo currently has issued a total of 54,220,000 shares. Some of Masimo'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. Masimo currently has a public float of 49,950,000 shares. How does Masimo's short interest compare to its competitors? 6.57% of Masimo's shares are currently sold short. Here is how the short interest of companies in the sector of "medical" compare to Masimo: AMN Healthcare Services Inc (11.50%), Veeva Systems Inc. (3.38%), DexCom, Inc. (2.40%), STERIS plc (0.74%), Insulet Corporation (2.72%), Baxter International Inc. (3.34%), Hologic, Inc. (2.28%), Globus Medical, Inc. (4.21%), Teleflex Incorporated (2.37%), Integer Holdings Corporation (6.39%), 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 ($69.26 billion), Invesco QQQ ($25.22 billion), iShares Russell 2000 ETF ($20.33 billion), iShares 20+ Year Treasury Bond ETF ($9.99 billion), MicroStrategy Incorporated ($9.12 billion), Canadian Natural Resources Limited ($6.73 billion), SPDR S&P Biotech ETF ($6.52 billion), Invesco S&P 500 Equal Weight ETF ($5.60 billion), Financial Select Sector SPDR Fund ($4.64 billion), and iShares iBoxx $ Investment Grade Corporate Bond ETF ($4.59 billion). View all of the most shorted stocks. What does it mean to sell short Masimo stock? Short selling MASI is an investing strategy that aims to generate trading profit from Masimo as its price is falling. MASI shares are trading down $3.67 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 Masimo? A short squeeze for Masimo 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 MASI, which in turn drives the price of the stock up even further. How often is Masimo'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 MASI, twice per month. The most recent reporting period available is June, 15 2025. More Short Interest Resources from MarketBeat Related Companies AMN Short Squeeze VEEV Short Squeeze DXCM Short Squeeze STE Short Squeeze PODD Short Squeeze BAX Short Squeeze HOLX Short Squeeze GMED Short Squeeze TFX Short Squeeze ITGR Short Squeeze Short Interest Tools Stocks to Short Largest Short Interest Positions Short Interest Increases Short Interest Decreases Short Interest Reporting Dates This page (NASDAQ:MASI) was last updated on 7/5/2025 by MarketBeat.com Staff From Our PartnersBanks aren’t ready for this altcoin—are you?Our expert analysts have identified a $100 billion gap in the crypto market. Only one project is perfectly ...Crypto 101 Media | SponsoredA new rule goes live in July — and the banks are quietly cashing inA little-known regulation quietly goes into effect this July. And it's already being exploited by Wall Stre...American Alternative | SponsoredIs Elon's empire crumbling?The Tesla Shock Nobody Sees Coming While headlines scream "Tesla is doomed"... 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