It would be fine if it were only an exchange. If the only assets are those of the customers deposited, then everyone can withdraw at the same time without issu

It would be fine if it were only an exchange. If the only assets are those of the customers deposited, then everyone can withdraw at the same time without issue. The problem is that they are also lending on margin, which means they are lending customers money to use to buy more crypto. Each customer has their margin loan secured by the crypto in their account, but in a steep drop in crypto valuations, the value of the crypto can drop below the loan principal. And if individuals don't cough up the cash to pay the balance, the exchange is on the hook for it. And it gets worse. Where does the exchange get the cash to lend in the first place? They borrow it, of course. And like the individual traders use the securities in their account as collateral for their loans, the brokerage uses all of the securities they hold as collateral for their loan. Problem is that they don't own these securities, but rather hold them on behalf of customers. So in a situation where the exchange as a whole is undercolateralized, the brokerage as a whole can get a margin call. And then they will have to liquidate securities they hold (your crypto). This means that even if you are a customer with a low risk portfolio, you can lose your securities because the exchange took on risk to finance someone else's risky trade. This exact process happened at MF Global back in the financial crisis, and would have happened to a lot more firms if the government hadn't bailed them out. Margin lending in the stock market is heavily regulated, and I'm sure you can see why. Crypto is the wild west. A lot of lessons were learned about this in the crash of 1929, and the crypto market is learning them now.