Amid the fallout of the implosion of FTX, once the second-largest cryptocurrency exchange, at least $1bn in investor assets appears to be missing, according to multiple reports. On Saturday morning, Reuters reported that FTX was missing at least $1bn in client funds, according to two anonymous sources who held senior positions at FTX and said they had been briefed on the company’s finances. The sources claimed the funds were part of $10bn in client funds that the FTX founder, Sam Bankman-Fried, secretly transferred to Alameda Research, the hedge fund he owns. A later report from the Wall Street Journal added that it appeared hackers had actually taken $370m. The moving of FTX funds to Alameda was one of a series of crises that led to FTX filing for bankruptcy and Bankman-Fried’s resignation on Friday. Bankman-Fried told Reuters that he “disagreed with the characterization” of the transfer, saying: “We had confusing internal labeling and misread it.” When asked about the missing customer funds over text message by Reuters, Bankman-Fried replied with: “???” Separately, in a tweet on Saturday, FTX’s US general counsel, Ryne Miller, said that the company had detected “unauthorized transactions” and that it had moved all digital assets to cold storage, or offline, as a precaution. Elliptic, a cryptocurrency analytics and compliance firm, estimates that $473m in crypto assets were stolen from FTX last Friday night, though the specific amount has not been confirmed. Bankman-Fried, 30, was hailed as a crypto titan until the descent of FTX over the last week. He was a major donor to the Democratic party, with a net worth that was once $17bn, and had goals of shaping how the world, especially policymakers in Washington DC, saw cryptocurrency. But FTX’s digital currency, FTT, collapsed within a matter of days. Investors, particularly Binance, the largest cryptocurrency exchange, learned that much of Alameda’s assets were held in FTT, making the company vulnerable to the currency’s fluctuating value. Binance’s Changpeng Zhao, a crypto star in his own right, announced that his company would be liquidizing its FTT, a move that would ultimately cause a run on the asset and collapse its value. FTX announced on Friday that it declared bankruptcy and Bankman-Fried had resigned. “I’m deeply sorry that we got into this place and for my role in it,” Bankman-Fried told employees on Tuesday morning, days before his resignation. “I fucked up.” In an interview published by Bloomberg on Saturday, the US treasury secretary, Janet Yellen, said that the fiasco confirmed her view that cryptocurrency needs “very careful regulation”. “It shows the weakness of this entire sector,” Yellen said. She noted that in regulated exchanges, customer assets are segregated, saying: “The notion that you could use the deposits of customers of an exchange and lend them to a separate enterprise that you control to do leveraged, risky investments – that wouldn’t be something that’s allowed.” Yellen also said: “At least it’s not deeply integrated with our banking sector and, at this point, doesn’t pose broader threats to financial stability.”