According to a sworn declaration in Mt. Gox’s U.S. bankruptcy filing, the company may have collected a large sum in trading fees in the weeks before its closure, even though it was already aware that a vast number of Bitcoins had gone missing. Even though Mt Gox told customers it was investigating possible fraud on Feb 7, due to a security issue called transaction malleability, buying and selling on the exchange continued until Feb. 25.
According to Bitcoincharts.com, an average of 49,912 bitcoins were traded daily on Mt. Gox between Feb. 7 and Feb. 25, at an average weighted price of $380.54 per bitcoin.