Japan Bitcoin Mt_Cham640A major bitcoin exchange has gone bust after secretly racking up catastrophic losses, other virtual currency companies said Tuesday — a potentially fatal blow for the exotic new form of money. The website of Tokyo-based Mt. Gox was returning a blank page Tuesday. The disappearance of the site follows the resignation Sunday of Mt. Gox CEO Mark Karpeles from the board of the Bitcoin Foundation, a group seeking legitimacy for the currency, and a withdrawal ban imposed at the exchange earlier this month. Prominent members of the Bitcoin community — including San Francisco-based wallet service Coinbase and Chinese exchange BTC China — sought to shore up confidence in the currency by saying Mt. Gox’s collapse was an isolated case of mismanagement. They said it had abused users’ trust, but did not offer details on how. More