Funny how the replies are full of people explaining how bank deposits work. An exchange is not a bank. They're a custodian that holds something on the customer's behalf and facilitates trades. That crypto "exchanges" act like banks, but without any of the banking regulation we spent the last 100 years learning the hard way is why they keep failing.
My stock broker and the NYSE can't secretly sell my shares and loan out the proceeds. They just hold the stock.
That Crypto "exchanges" think of deposits as assets makes it clear they're more like a hedge fund than a bank or exchange.