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iShares Biotechnology ETF (IBB) Short Interest Ratio & Short Volume

iShares Biotechnology ETF logo
$210.53 -0.51 (-0.24%)
Closing price 04:00 PM Eastern
Extended Trading
$210.25 -0.28 (-0.13%)
As of 07:40 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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iShares Biotechnology ETF Short Interest Overview

As of September 15, 2026, iShares Biotechnology ETF (IBB) had a short interest of 12.27 million shares sold short, representing 24.17% of the public float. This marks a 11.67% increase in short interest since the prior report. The short interest ratio (days to cover) is 7.9, meaning it would take 7.9 days of the average trading volume of 1.42 million shares to cover all short positions.

Current Short Interest
12,267,170 shares
Previous Short Interest
10,985,379 shares
Change Vs. Previous Month
11.67%
Dollar Volume Sold Short
$2.48 billion
Short Interest Ratio
7.9 Days to Cover
Last Record Date
September 15, 2026
Outstanding Shares
50,650,000 shares
Short Percent of Float
24.17%
Today's Trading Volume
1,939,160 shares
Average Trading Volume
1,423,179 shares
Today's Volume Vs. Average
136%
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Short Interest ChartDays to Cover ChartShort Percent of Float Chart

IBB Short Interest Over Time

IBB Days to Cover Over Time

IBB Percentage of Float Shorted Over Time

iShares Biotechnology ETF 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
9/15/202612,267,170 shares $2.48 billion +11.7%24.2%7.85 $202.00
8/31/202610,985,379 shares $2.30 billion +5.2%21.7%6.63 $209.05
8/14/202610,440,435 shares $2.07 billion +4.0%21.1%7.36 $198.26
7/31/202610,042,470 shares $1.87 billion -15.7%20.5%7.06 $186.41
7/15/202611,909,708 shares $2.26 billion -1.6%23.8%6.42 $189.90
6/30/202612,108,341 shares $2.30 billion -2.6%25.0%7.08 $190.19
6/15/202612,435,411 shares $2.14 billion -6.1%26.6%8.73 $172.17
5/29/202613,243,596 shares $2.28 billion +1.8%27.9%8.78 $172.18
5/15/202613,009,363 shares $2.17 billion -1.9%27.8%9.67 $166.83
4/30/202613,267,269 shares $2.24 billion +5.4%28.2%9.08 $168.69
4/15/202612,584,040 shares $2.21 billion -5.4%26.5%9.39 $175.99
3/31/202613,298,650 shares $2.25 billion -7.1%26.5%7.84 $168.85
3/13/202614,315,391 shares $2.37 billion -3.9%29.4%7.65 $165.51
2/27/202614,892,958 shares $2.61 billion -1.1%30.1%9.32 $175.37
2/13/202615,059,984 shares $2.60 billion +18.4%32.2%6.94 $172.57
1/30/202612,721,468 shares $2.19 billion +0.2%25.8%7.48 $172.43
1/15/202612,700,561 shares $2.17 billion +0.8%25.7%6.17 $170.56
12/31/202512,595,742 shares $2.13 billion -5.9%25.2%8.52 $168.77
12/15/202513,378,601 shares $2.27 billion +9.5%26.8%8.09 $169.38
11/28/202512,218,668 shares $2.12 billion -1.2%24.2%4.09 $173.63
11/14/202512,364,326 shares $2.03 billion +4.8%25.1%4.81 $164.19
10/31/202511,794,089 shares $1.88 billion +0.8%27.4%6.03 $159.38
10/15/202511,700,000 shares $1.79 billion -6.8%28.1%6.4 $153.39
9/30/202512,550,000 shares $1.81 billion +15.9%N/A7.4 $144.37
9/15/202510,830,000 shares $1.52 billion +3.8%N/A6.8 $140.72
8/31/202510,430,000 shares $1.44 billion No Change25.9%6.3 $138.22
5/15/202512,860,000 shares $1.53 billion +15.7%29.4%7.7 $119.24
4/30/202511,120,000 shares $1.41 billion +6.8%N/A6.9 $126.58
4/15/202510,410,000 shares $1.25 billion +7.1%23.6%7.1 $119.85
3/31/20259,720,000 shares $1.24 billion -1.0%21.2%6.7 $127.90
3/15/20259,820,000 shares $1.32 billion +4.8%20.8%7.4 $134.19
2/28/20259,370,000 shares $1.28 billion +2.5%19.8%6.7 $137.03
2/15/20259,140,000 shares $1.25 billion -9.4%19.3%6.4 $136.55
1/31/202510,090,000 shares $1.40 billion -9.2%N/A6.7 $138.66
1/15/202511,110,000 shares $1.48 billion -1.1%N/A7.7 $133.42
12/31/202411,230,000 shares $1.48 billion -3.8%N/A8.4 $132.21
12/15/202411,670,000 shares $1.59 billion +3.6%N/A9 $136.61
11/30/202411,260,000 shares $1.59 billion +9.5%N/A9.1 $141.55
11/15/202410,280,000 shares $1.37 billion +1.4%N/A8.6 $133.38
10/31/202410,140,000 shares $1.42 billion +3.3%N/A9.8 $140.29
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10/15/20249,820,000 shares $1.43 billion +1.5%N/A8.8 $145.82
9/30/20249,680,000 shares $1.41 billion +4.1%N/A8 $145.60
9/15/20249,300,000 shares $1.37 billion -8.6%N/A7.4 $147.81
8/31/202410,180,000 shares $1.51 billion +0.4%N/A8.3 $148.17
8/15/202410,140,000 shares $1.47 billion -7.2%N/A7.7 $144.95
7/31/202410,930,000 shares $1.62 billion -10.5%N/A8 $147.97
7/15/202412,210,000 shares $1.77 billion No ChangeN/A8.7 $145.15
1/15/20248,740,000 shares $1.20 billion +4.3%N/A4.6 $137.13
12/31/20238,380,000 shares $1.14 billion -14.1%N/A4.2 $135.85
12/15/20239,760,000 shares $1.29 billion -8.9%N/A4.7 $131.78
11/30/202310,710,000 shares $1.30 billion +5.6%N/A5.5 $120.93
11/15/202310,140,000 shares $1.20 billion -3.9%N/A5.2 $118.03
10/31/202310,550,000 shares $1.20 billion +6.5%N/A5.7 $113.68
10/15/20239,910,000 shares $1.21 billion -2.5%N/A6 $121.63
9/30/202310,160,000 shares $1.24 billion +7.7%N/A6.7 $122.29
9/15/20239,430,000 shares $1.19 billion -7.0%N/A6.6 $126.61
8/31/202310,140,000 shares $1.31 billion -0.4%N/A6.6 $128.71
8/15/202310,180,000 shares $1.30 billion +1.9%N/A6.6 $128.01
7/31/20239,990,000 shares $1.29 billion +2.7%N/A6.3 $129.31
7/15/20239,730,000 shares $1.25 billion -7.3%N/A6 $128.24
6/30/202310,500,000 shares $1.33 billion +0.4%N/A6.5 $126.96
6/15/202310,460,000 shares $1.38 billion +10.2%N/A6.7 $131.81
5/31/20239,490,000 shares $1.20 billion +1.3%N/A6 $126.28
5/15/20239,370,000 shares $1.23 billion -6.4%N/A6 $131.74
4/30/202310,010,000 shares $1.31 billion +2.5%N/A6.4 $130.51
4/15/20239,770,000 shares $1.29 billion -0.8%N/A6.3 $132.43
3/31/20239,850,000 shares $1.27 billion -6.5%N/A6.4 $129.16
3/15/202310,530,000 shares $1.33 billion +12.4%N/A6.7 $126.06
2/28/20239,370,000 shares $1.19 billion -7.0%N/A6.2 $127.18
2/15/202310,070,000 shares $1.35 billion +6.7%N/A6.4 $133.77
1/31/20239,440,000 shares $1.29 billion -4.4%N/A5.6 $136.55
1/15/20239,870,000 shares $1.34 billion -5.5%N/A5.6 $136.23
12/30/202210,440,000 shares $1.37 billion +4.7%N/A5.7 $131.29
12/15/20229,970,000 shares $1.34 billion -8.8%N/A5.2 $134.24
11/30/202210,930,000 shares $1.49 billion +5.0%N/A5.5 $136.53
11/15/202210,410,000 shares $1.41 billion +6.9%N/A5.3 $135.11
10/31/20229,740,000 shares $1.25 billion -15.4%N/A5.1 $128.59
10/15/202211,510,000 shares $1.38 billion No ChangeN/A6.2 $119.58
9/30/20229,180,000 shares $1.07 billion +16.8%N/A4.9 $116.96
9/15/20227,860,000 shares $975.03 million +12.8%N/A4.1 $124.05
8/31/20226,970,000 shares $846.58 million -19.6%N/A3.5 $121.46
8/15/20228,670,000 shares $1.17 billion +14.4%N/A4.3 $134.82
7/31/20227,580,000 shares $940.53 million -2.3%N/A3.2 $124.08
7/15/20227,760,000 shares $956.42 million -12.7%N/A3 $123.25
6/30/20228,890,000 shares $1.05 billion +1.1%N/A3.3 $117.63
6/15/20228,790,000 shares $955.12 million +12.7%N/A3.2 $108.66
5/31/20227,800,000 shares $910.03 million -6.0%N/A2.9 $116.67
5/15/20228,300,000 shares $939.06 million +3.2%N/A3 $113.14
4/30/20228,040,000 shares $937.87 million -6.9%N/A3 $116.65
4/15/20228,640,000 shares $1.13 billion -9.5%N/A3.2 $130.86
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3/31/20229,550,000 shares $1.24 billion -20.2%N/A3.5 $130.30
3/15/202211,970,000 shares $1.45 billion +6.2%N/A4.4 $121.13
2/28/202211,270,000 shares $1.42 billion +10.5%N/A4.1 $126.07
2/15/202210,200,000 shares $1.33 billion -4.5%N/A3.6 $129.98
1/31/202210,680,000 shares $1.41 billion +4.3%N/A4 $131.86
1/15/202210,240,000 shares $1.42 billion +9.6%N/A4.1 $138.95
12/31/20219,340,000 shares $1.43 billion -9.3%N/A4.3 $152.62
12/15/202110,300,000 shares $1.56 billion -1.4%N/A4.7 $151.90
11/30/202110,450,000 shares $1.61 billion -11.3%N/A5 $154.22
11/15/202111,780,000 shares $1.80 billion +6.9%N/A6 $153.18
10/29/202111,020,000 shares $1.76 billion -0.1%N/A5.2 $159.60
10/15/202111,030,000 shares $1.73 billion -14.6%N/A4.9 $157.06
9/30/202112,920,000 shares $2.09 billion +10.6%N/A5.1 $161.68

IBB Short Interest - Frequently Asked Questions

Short interest is the volume of iShares Biotechnology ETF shares that have been sold short but have not yet been closed out or covered. As of September 15th, investors have sold 12,267,170 shares of IBB short. 24.17% of iShares Biotechnology ETF's shares are currently sold short. Learn More on iShares Biotechnology ETF's 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. IBB shares currently have a short interest ratio of 7.9. Learn More on iShares Biotechnology ETF'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. 24.17% of iShares Biotechnology ETF's floating shares are currently sold short.

iShares Biotechnology ETF saw a increase in short interest in September. As of September 15th, there was short interest totaling 12,267,170 shares, an increase of 11.7% from the previous total of 10,985,379 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.

24.17% of iShares Biotechnology ETF's shares are currently sold short. Here is how the short interest of companies compare to iShares Biotechnology ETF: VanEck Pharmaceutical ETF (26.56%), VanEck Biotech ETF (1.03%), Invesco Dorsey Wright Healthcare Momentum ETF (0.53%), Invesco S&P SmallCap Health Care ETF (0.19%), F/m Emerald Life Sciences Innovation ETF (0.89%), and First Trust Nasdaq Pharmaceuticals ETF (0.07%).

As of the most recent reporting period, the following stocks had the largest short interest positions: SPDR S&P 500 ETF Trust ($75.21 billion), Invesco QQQ ($46.31 billion), iShares Russell 2000 ETF ($27.98 billion), SPDR S&P Biotech ETF ($11.59 billion), Nebius Group N.V. ($9.70 billion), Canadian Natural Resources Limited ($9.42 billion), iShares 20+ Year Treasury Bond ETF ($8.70 billion), iShares iBoxx $ High Yield Corporate Bond ETF ($8.53 billion), iShares iBoxx $ Investment Grade Corporate Bond ETF ($7.79 billion), and Financial Select Sector SPDR Fund ($7.74 billion). View all of the most shorted stocks.

Short selling IBB is an investing strategy that aims to generate trading profit from iShares Biotechnology ETF as its price is falling. IBB shares are trading down $0.51 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 iShares Biotechnology ETF 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 IBB, 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 IBB, twice per month. The most recent reporting period available is September, 15 2026.

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

  • 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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Short Interest Tools

Short interest data for NASDAQ:IBB is sourced from the Financial Industry Regulatory Authority (FINRA), with the most recent report published on 9/24/2026. FINRA publishes updated short interest twice a month.
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