Short interest is reported twice monthly. It is MM's that use shorting to facilitate trades. Not those of us using brokerages. MM's function by shorting on a daily basis. I've read that up to 90% of trades on a given day may be short. That's because Mm's 'borrow' the shares to sell to buyers, then cover shortly thereafter. If they don't cover by the close, it is called 'short interest', and is reported BY MM's twice a month. It has nothing to do with shareholders.