$GME Short-sellers lost $818 mln on Gamestop bets on Wednesday - Ortex LONDON, Feb 25 (Reuters) - Short-sellers are estimated to have lost $818 million on Wednesday from their bearish bets on videogame maker Gamestop , data from financial analytics firm Ortex showed. GameStop's shares shot up higher again on Thursday a day after doubling in value, sparking a fresh retail trading frenzy in the stock that had been at the center of a historic short squeeze in January.