I'd be shocked if they had any solid claim at even $1B using honest numbers. The crypto world loves to make valuations like “I just sold one to my buddy at $500, the other tokens are worth $45 trillion” but at the end of the day there just wasn't that much liquidity since most people aren't interested in the product. For a company like FTX which is getting fees from their customer's holdings that doesn't leave a lot of room for billions unless they could have cashed out at the peak of the bubble.