An FTX user wrote to the host interviewing Sam Bankman-Fried at a New York Times summit.
He said he lost $2 million and accused SBF of stealing it.
"I am deeply sorry about what happened," Bankman-Fried said.
Sam Bankman-Fried apologized to an FTX user who said he lost $2 million after the crypto exchange went bankrupt.
The controversial "Crypto King" was interviewed at the New York Times DealBook Summit on Wednesday evening, and one of his previous customers wrote in to demand answers.
Andrew Ross Sorkin - the journalist hosting the summit - shared the email "from a gentleman who said he lost his life savings." It had the subject line: "Sam Bankman-Fried stole $2 million from me."
"Please ask him if he thinks what happened was fraud."
Sorkin added that he had gotten several similar letters, before asking Bankman-Fried: "What do you tell this man?"
"I am deeply sorry about what happened," he replied.
Bankman-Fried added that the FTX.US platform was still "fully funded" and he believed withdrawals "could be opened up today."
He then went on a long explanation of Alameda's risky trade positions, before blaming an "all-out PR assault, which led to a total market collapse in a pretty short period of time."
But Sorkin then raised the question of money being mixed between Alameda and FTX.
On November 11, The Wall Street Journal reported that FTX lent $10 billion of customer assets to Alameda for its high-risk bets.
The customer had also referenced the FTX terms of service in his email, which said: "None of the digital assets in your account are the property of, or shall or may be loaned to, FTX Trading."
Under further questioning from Sorkin about the close-ties between his companies, Bankman-Fried eventually said: "I didn't knowingly commingle funds."
Later on in the DealBook interview, SBF also said he doesn't think he's "criminally liable" for FTX's implosion.
Recent bankruptcy documents have shown that FTX didn't have an accounting department, while company expenses were approved by emojis on online chats.
One former employee told the Financial Times: "It just kinda went crazy. If Sam said OK, it was good to go. Regardless of the amount."