Right, but irresponsible banks have done that before and, at the very least, that is self-liquidating on the way down (the same with companies issuing stock to employees).
And whether they are gambling with your money or not, they were a mix of a bank and an exchange...so the comparison with a bank isn't complete. They were booking derivatives trades so your money is 100% at-risk, irregardless of what they do with customer deposits. This is what prime brokers do (as Levine says in that article).
The reason you don't lend against your own shares is because you won't be able to get financing and are exposed to runs. It is unrelated to the point about customers who were already at risk because they were trading derivatives issued by FTX.
And whether they are gambling with your money or not, they were a mix of a bank and an exchange...so the comparison with a bank isn't complete. They were booking derivatives trades so your money is 100% at-risk, irregardless of what they do with customer deposits. This is what prime brokers do (as Levine says in that article).
The reason you don't lend against your own shares is because you won't be able to get financing and are exposed to runs. It is unrelated to the point about customers who were already at risk because they were trading derivatives issued by FTX.