This is how the FTX-Alameda perpetual motion machine worked. Alameda was a bad/failing prop trading firm. FTX appeared to be valuable because smarter firms were attracted to the exchange by the opportunity to take money from Alameda. In order to perpetuate the appearance, FTX had to inject money into Alameda, so Alameda could continue their negative strategies, so the exchange appeared to be busy. The more Alameda lost, the more smarter people showed up to take their money, and the faster FTX had to shovel funds into the hole. This abruptly stopped working as soon as inflows to FTX stopped arriving.

The whole scheme has now entered the "whoopsie we got hacked" phase that inevitably concludes every crypto scam, in which the insiders are liquidating and laundering depositor's coins, and buying real estate in non-extradition countries.