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Cerus (CERS) Short Interest Ratio & Short Volume

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$2.71 -0.08 (-2.87%)
Closing price 06/5/2026 04:00 PM Eastern
Extended Trading
$2.74 +0.02 (+0.92%)
As of 06/5/2026 06:19 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 Massive. Learn more.
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Cerus Short Interest Overview

As of May 15, 2026, Cerus (CERS) had a short interest of 18.52 million shares sold short, representing 9.79% of the public float. This marks a 64.31% increase in short interest since the prior report. The short interest ratio (days to cover) is 4.0, meaning it would take 4.0 days of the average trading volume of 2.34 million shares to cover all short positions.

Current Short Interest
18,522,745 shares
Previous Short Interest
11,273,044 shares
Change Vs. Previous Month
64.31%
Dollar Volume Sold Short
$43.34 million
Short Interest Ratio
4.0 Days to Cover
Last Record Date
May 15, 2026
Outstanding Shares
200,370,000 shares
Short Percent of Float
9.79%
Today's Trading Volume
1,607,550 shares
Average Trading Volume
2,343,313 shares
Today's Volume Vs. Average
69%
Short Selling Cerus?
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Short Interest ChartDays to Cover ChartShort Percent of Float Chart

CERS Short Interest Over Time

CERS Days to Cover Over Time

CERS Percentage of Float Shorted Over Time

Cerus Tesla Short Interest History & Recent Changes

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Report DateTotal Shares Sold ShortDollar Volume Sold ShortChange from Previous ReportPercentage of Float ShortedDays to CoverPrice on Report Date
5/15/202618,522,745 shares $43.34 million +64.3%9.8%4 $2.34
4/30/202611,273,044 shares $22.88 million +0.6%5.8%10.51 $2.03
4/15/202611,204,876 shares $22.63 million +0.8%6.2%12.45 $2.02
3/31/202611,119,137 shares $20.24 million +5.8%6.1%6.3 $1.82
3/13/202610,511,205 shares $17.76 million +35.1%5.7%3.61 $1.69
2/27/20267,781,596 shares $19.92 million -0.5%4.2%5.69 $2.56
2/13/20267,818,308 shares $17.51 million +16.3%4.2%8.01 $2.24
1/30/20266,725,116 shares $15.67 million -5.9%3.6%5.93 $2.33
1/15/20267,143,959 shares $19.57 million +6.4%3.9%3.62 $2.74
12/31/20256,714,909 shares $13.83 million +7.6%3.6%4.85 $2.06
12/15/20256,239,300 shares $12.54 million +6.9%3.4%3.6 $2.01
11/28/20255,838,160 shares $10.30 million +2.1%3.1%4.46 $1.77
11/14/20255,720,796 shares $9.27 million +9.6%3.2%4.11 $1.62
10/31/20255,222,244 shares $7.68 million +1.0%2.9%4.72 $1.47
10/15/20255,170,000 shares $8.22 million -16.5%2.8%3.9 $1.59
9/30/20256,190,000 shares $9.84 million -43.8%N/A4.9 $1.59
9/15/202511,020,000 shares $13.22 million +59.7%N/A8.7 $1.20
8/31/20256,900,000 shares $9.04 million -29.2%3.8%6.3 $1.31
8/15/20259,740,000 shares $12.08 million +38.9%N/A7.9 $1.24
7/31/20257,010,000 shares $8.97 million -5.1%3.9%6 $1.28
7/15/20257,390,000 shares $9.98 million -7.2%N/A6.4 $1.35
6/30/20257,960,000 shares $11.22 million +18.5%4.4%6.4 $1.41
6/15/20256,720,000 shares $8.87 million -25.7%3.7%5.5 $1.32
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
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
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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 $1.29
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
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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 $6.19
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

CERS Short Interest - Frequently Asked Questions

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 15th, traders have sold 18,522,745 shares of CERS short. 9.79% of Cerus' shares are currently sold short. Learn More on Cerus' current short interest.

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 4.0. Learn More on Cerus's short interest ratio.

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. 9.79% of Cerus' floating shares are currently sold short.

Cerus saw a increase in short interest in the month of May. As of May 15th, there was short interest totaling 18,522,745 shares, an increase of 64.3% from the previous total of 11,273,044 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.

9.79% of Cerus' shares are currently sold short. Here is how the short interest of companies in the sector of "medical" compare to Cerus: DENTSPLY SIRONA Inc. (11.89%), Neogen Corporation (4.96%), STAAR Surgical Company (19.69%), QuidelOrtho Corporation (17.43%), OraSure Technologies, Inc. (4.64%), Utah Medical Products, Inc. (4.53%), Anika Therapeutics Inc. (4.83%), West Pharmaceutical Services, Inc. (3.25%), Align Technology, Inc. (6.92%), The Cooper Companies, Inc. (2.68%),

As of the most recent reporting period, the following stocks had the largest short interest positions: SPDR S&P 500 ETF Trust ($80.71 billion), Invesco QQQ ($47.96 billion), iShares Russell 2000 ETF ($22.13 billion), Western Digital Corporation ($14.35 billion), Sandisk Corporation ($12.86 billion), Salesforce Inc. ($10.89 billion), Nebius Group N.V. ($9.92 billion), SPDR S&P Biotech ETF ($9.72 billion), Lumentum Holdings Inc. ($8.89 billion), and iShares 20+ Year Treasury Bond ETF ($8.18 billion). View all of the most shorted stocks.

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 $0.08 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.

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.

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, 15 2026.

Understanding short interest metrics can help you assess how traders are positioning around a stock like CERS:

  • Shares Sold Short: The total number of shares that have been sold by short sellers but have not yet been covered or closed out. A high number may indicate bearish sentiment.
  • Short Float: The percentage of a company’s publicly available shares (or "float") that are sold short. A higher short float suggests a greater portion of the stock is being bet against.
  • Days to Cover (Short Interest Ratio): This estimates how many days it would take short sellers to cover their positions, based on average daily trading volume. Higher values can signal potential for a short squeeze if buying pressure increases.

These metrics are often used by traders to gauge sentiment, volatility risk, and the potential for price movements based on short covering activity.


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This page (NASDAQ:CERS) was last updated on 6/6/2026 by MarketBeat.com Staff.
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