Can you explain why BUYS are FTD.
I believe you mean, why a buy would show up as a short sale. Well, if you take into consideration that whether a trade takes place on the bid or the ask, there's still two sides to every trade, it might help. Not unlike on the bid, the MM's can see how many shares are up for sale on the ask. So, if someone wants to buy at the ask, they fill that buy order, then turn around and execute someones sell order to cover those shares. I find that normally the short sale percentage is higher on trades executed on the ask, most likely because MM's are less likely to be holding inventory of higher priced shares.