That is the daily short volume reported to FINRA as requested by the SEC by the market makers exclusive of T trades. The cumulative short sales are rarely known as they are hidden in ex clearing and CNS for the most part. The only way to find out the exact size of the short would be to have all shares distributed in certificate form and that just doesn't happen.. Virtually all OTC stocks are naked shorted. This shorting is not by retail rather it is by the investment banks, insurance companies, hedge funds and offshore entities. This site has lots more information and documentation for those who want to know more: