At least $1 billion of customer funds have vanished from collapsed crypto exchange FTX, according to two people familiar with the matter. The exchange's founder Sam Bankman-Fried secretly transferred $10 billion of customer funds from FTX to Bankman-Fried's trading company Alameda Research, the people told Reuters. A large portion of that total has since disappeared, they said. One source put the missing amount at about $1.7 billion. The other said the gap was between $1 billion and $2 billion. In a subsequent examination, FTX legal and finance teams also learned that Bankman-Fried implemented a "backdoor" in FTX's book-keeping system, which was built using bespoke software. They said the "backdoor" allowed Bankman-Fried to execute commands that could alter the company's financial records without alerting other people, including external auditors. This set-up meant that the movement of the $10 billion in funds to Alameda did not trigger internal compliance or accounting red flags at FTX, they said.