Distinguishing Daily Short Volume from Reported Short Interest
Summary
The document explains how retail investors can find public data about short selling and why daily short volume is different from short interest. Short volume counts reported short-sale activity over a period; short interest estimates open short positions and is generally reported twice monthly. It describes sources including FINRA, Nasdaq, and NYSE, with examples of downloading daily files and looking up reported figures for a symbol.
The central caveat is that daily short-volume data is incomplete: FINRA says it excludes some trades, is not consolidated with exchange data, and is not intended to represent outstanding short positions. Exchange coverage also varies, and some short-interest data may require payment. The sample ranking and ticker records illustrate how the figures are presented, but do not establish that high short volume means a stock has high short interest or predicts price direction.
Key ideas
- Daily short volume measures reported short-sale transactions, while short interest measures positions that remain open.
- FINRA publishes daily short-sale volume files and periodic short-interest reports.
- Nasdaq provides short-interest information for its listed stocks, while coverage differs across venues.
- Daily short-volume records omit some trades and should not be treated as a measure of outstanding short positions.
- Comparing short data with shares outstanding or float requires a separate source for those share counts.
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Full text
# Without Bloomberg, how can retail investors know how many shares have been shorted daily? # Without Bloomberg, how can retail investors know how many shares have been shorted daily? Many friends can't afford a Bloomberg terminal, particularly when the pandemic has unemployed some of them. This answer can't assist them. How else can amateur investors determine the number of shorted shares for a corporation? This Investopedia article suggests that they must pay their discount brokerage for this data? But do discount brokers even list daily short interest? I'm assuming any brokerage costs are less than a Bloomberg terminal. > The free data is updated just twice a month. Short interest tables will show information for the last two reporting dates. Daily short interest data is available but can only be purchased through a subscription. ## Answer by Sergei Rodionov (score 5, accepted) https://quant.stackexchange.com/a/60814 FINRA reports short volume and total volume on a subset of trades reported to its reporting facilities. Quoting FINRA, the data: ``` (1) does not include any trades that are not publicly disseminated, (2) is not consolidated with exchange data, and (3) does not—and is not intended to—equate to short interest position information. ``` You can view historical data on GME and other symbols in this visualization To download archives from NYSE: ``` wget -vvv --no-parent --recursive --level=2 --accept=.txt \ --no-directories ftp://ftp.nyxdata.com/ShortData/NYSEshvol/current ``` Top-50 by Short Volume on Jan-29. GME is ranked 43: ``` | dt | symbol | short_vol | total_vol | short_vol_% | |------------|--------|----------:|----------:|------------:| | 2021-01-29 | SNDL | 255689121 | 475322606 | 53.8 | | 2021-01-29 | AMC | 147053814 | 285512338 | 51.5 | | 2021-01-29 | NAKD | 130376400 | 250377016 | 52.1 | | 2021-01-29 | CATB | 88019172 | 186209530 | 47.3 | | 2021-01-29 | CTRM | 66297030 | 133717565 | 49.6 | | 2021-01-29 | NOK | 53711194 | 152948886 | 35.1 | | 2021-01-29 | GTE | 27725882 | 50123103 | 55.3 | | 2021-01-29 | AAPL | 27354158 | 79187985 | 34.5 | | 2021-01-29 | NAK | 24833606 | 46842197 | 53.0 | | 2021-01-29 | ZOM | 24376676 | 45657956 | 53.4 | | 2021-01-29 | LMFA | 21944109 | 40080570 | 54.7 | | 2021-01-29 | GNUS | 21644515 | 41826558 | 51.7 | | 2021-01-29 | UVXY | 20743744 | 79407556 | 26.1 | | 2021-01-29 | SOS | 16088533 | 46631095 | 34.5 | | 2021-01-29 | SPY | 15698791 | 25795811 | 60.9 | | 2021-01-29 | AAL | 15665027 | 45389480 | 34.5 | | 2021-01-29 | VXRT | 15637860 | 36938038 | 42.3 | | 2021-01-29 | NIO | 14792052 | 40733405 | 36.3 | | 2021-01-29 | TRX | 14687288 | 41716348 | 35.2 | | 2021-01-29 | BB | 14683994 | 38688694 | 38.0 | | 2021-01-29 | SQQQ | 14666607 | 48865446 | 30.0 | | 2021-01-29 | NMTR | 13979629 | 25901939 | 54.0 | | 2021-01-29 | SHIP | 13733182 | 28301043 | 48.5 | | 2021-01-29 | TOPS | 13541423 | 23691414 | 57.2 | | 2021-01-29 | EXPR | 13433628 | 25304445 | 53.1 | | 2021-01-29 | SLV | 13402058 | 31189141 | 43.0 | | 2021-01-29 | JAGX | 12784280 | 25936977 | 49.3 | | 2021-01-29 | GE | 11856734 | 43054245 | 27.5 | | 2021-01-29 | HYG | 11657915 | 16485402 | 70.7 | | 2021-01-29 | AIKI | 11297734 | 20401543 | 55.4 | | 2021-01-29 | MARA | 11140822 | 20035757 | 55.6 | | 2021-01-29 | BNGO | 10550275 | 20531616 | 51.4 | | 2021-01-29 | SENS | 10492468 | 20885436 | 50.2 | | 2021-01-29 | TNXP | 10416933 | 19741409 | 52.8 | | 2021-01-29 | PLTR | 10293959 | 18942966 | 54.3 | | 2021-01-29 | AAU | 9652743 | 18314149 | 52.7 | | 2021-01-29 | PHUN | 9605440 | 19311343 | 49.7 | | 2021-01-29 | MUX | 9174288 | 18127181 | 50.6 | | 2021-01-29 | TLRY | 9156301 | 15952683 | 57.4 | | 2021-01-29 | VXX | 9059395 | 27222555 | 33.3 | | 2021-01-29 | F | 9030503 | 25513486 | 35.4 | | 2021-01-29 | TZA | 8841975 | 26090511 | 33.9 | | 2021-01-29 | GME | 8814229 | 16327706 | 54.0 | | 2021-01-29 | XLF | 8779758 | 17878233 | 49.1 | | 2021-01-29 | AMD | 8353421 | 22133293 | 37.7 | | 2021-01-29 | NXTD | 8295327 | 19064715 | 43.5 | | 2021-01-29 | SH | 8287847 | 13130806 | 63.1 | | 2021-01-29 | TSLA | 7821075 | 13801262 | 56.7 | | 2021-01-29 | CCL | 7785300 | 19885426 | 39.2 | | 2021-01-29 | DD | 7471890 | 13022699 | 57.4 | ``` ## Answer by Dimitri Vulis (score 15) https://quant.stackexchange.com/a/60795 There are two different data items. "Short volume" (generally available daily) measures the number of shares that have been shorted in the given period of time, while "short interest" (generally available twice a month) is the number of shorted shares that have yet to be closed out or covered by the investors. The SI function on Bloomberg stands for short interest, but shows the short volume too. NASDAQ: Go to https://www.nasdaq.com/. Search for a ticker symbol, for example AAPL. This will take you to Apple's page. Click on "short interest" on the left. This will take you to https://www.nasdaq.com/market-activity/stocks/aapl/short-interest , which looks like a page designed with the ease of scraping in mind. Edit: thanks to Kirk Woll for pointing out that instead of scraping, you can go directly to https://api.nasdaq.com/api/quote/AAPL/short-interest?assetClass=stocks and parse that. Of course you can replace appl by any nasdaq ticker you like in the URL. But NASDAQ only shows this data for NASDAQ-listed stocks, not, for example, NYSE. FINRA (a U.S. self-regulatory organization) requires its members to report short interest twice a month. You can also see the reported data here: https://otce.finra.org/otce/equityShortInterest FINRA also has daily short sale volume files (not short interest) here: http://regsho.finra.org/regsho-Index.html For example, if you wanted to see how many shares of GME were shorted on January 28, 2021, you'd go to the link , download http://regsho.finra.org/CNMSshvol20210128.txt , and see a pipe-delimited text file containing the entire universe. You find the GME record: `Date|Symbol|ShortVolume|ShortExemptVolume|TotalVolume|Market 20210128|GME|9606123|455032|18899860|B,Q,N` If you wan to compare these volumes with the number of GME shares outstanding, you'll need to find the number of shares outstanding from a recently filed quarterly or annual report. There are many easy ways to find that. For example, you can go to Morningstar (again, you can change the exchange/ticker in the URL for another stock) and click on "short interest", and you will see figures labeled - Shares Outstanding - Float (the number of shares that are publicly owned, unrestricted and available on the open market) - Shares Short For the ICE / New York Stock Exchange (which includes Arca), according to https://www.nyse.com/market-data/reference/nyse-group-short-interest they want to be paid for their short sale interest data, which is also twice a month. However NYSE makes short sale volume data available for free via FTP. I think all of their volume data is also on the FINRA page above.
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