NEW YORK (MarketWatch) -- The virtual currency bitcoin jumped to a record of $947 Tuesday on the trading exchange Mt. Gox. In recent trade, one bitcoin bought $939.99 on Mt. Gox, the second-biggest exchange by volume, and $879 on BitStamp, the third-biggest exchange. Bitcoin had briefly pushed above $900 on Mt. Gox last week in the wake of a Senate hearing on virtual currencies.