But as Mt. Gox remained closed on Tuesday morning, one of Bitcoin’s most vocal cheerleaders portrayed the turmoil as an isolated problem.
The venture capitalist Marc Andreessen, whose firm has invested millions of dollars in Bitcoin-related start-ups, drew a comparison to MF Global, the brokerage firm that filed for bankruptcy in 2011.
“This is like MF Global, not some huge breakdown of the underlying technology or other exchanges,” Mr. Andreessen said in comments aired by CNBC on Tuesday morning. “Bitcoin protocol is unchanged and other Bitcoin exchanges and companies are doing fine.”
The price of Bitcoin extended its decline on Tuesday, hitting a low of about $419 before recovering somewhat to around $510, according to CoinDesk, news provider for virtual currencies. On Monday, it dipped below $500 for the first time since November, when it began a rally that it took it above $1,200.
A number of leading Bitcoin companies said on Monday that Mt. Gox, which handles about 6 percent of all Bitcoins in circulation, planned to file for bankruptcy after months of problems. A document circling widely in the Bitcoin world pointed to a theft of nearly all of Mt. Gox’s 744,000 Bitcoins, although the legitimacy of the document or its claim has not yet been verified.
“In the event of recent news reports and the potential repercussions on Mt. Gox’s operations and the market, a decision was taken to close all transactions for the time being in order to protect the site and our users,” said a statement on the Mt. Gox website on Tuesday. “We will be closely monitoring the situation and will react accordingly.”
Technology issues forced Mt. Gox to suspend withdrawals earlier this month, and many investors took to the online message board Reddit on Monday night to share how much they thought they had lost. “As much as I kick myself for not getting it out, I’m also patting myself on the back for getting most of my holdings out in time, when the writing on the wall became clearer,” said one user, whose claims could not be confirmed.
In his comments on television, Mr. Andreessen said Mt. Gox “has been obviously broken and possibly outright crooked for months.”
But his comparison to MF Global struck some observers as less than comforting. The saga surrounding MF Global, which collapsed when investors and ratings agencies became unnerved by its large position in European sovereign debt, raised broader questions about the safety of customer funds.
In MF Global’s case, $1.6 billion of customer money went missing, and clients questioned the oversight of the firm.