How To Tell A Pump is onthe fastest way to know if a stock is being pumped is watch the daily trading volumes. A pump will have on average 3 to 5 trading days of heavy trading volume then a sharp drop in volume happens when they run out of people to pump to until they build up more unsuspecting buyers then it starts again. Remember this the pumpers will sell into the heavy volume and buy it back when it drifts lower then sell again when the next round of pumping happens. This is a standard micro cap pump.