It was a T trade 500K after hours Definition Form T is an electronic form that FINRA requires brokers to use for reporting equity trades executed outside of normal market hours. Form T trades occur during extended hours — before the market opens and after it closes. ... In the OTC market, Form T trades are mostly the result of accumulated buys or sells handled on a not held basis by block desks, otherwise known as 'late prints.' They have nothing to do with short-selling.