Of course the actual stock or bond you are buying cannot be FDIC insured, nor any other investment. But the deposit and balance in your account can and should be FDIC insured. My TD Ameritrade cash and margin accounts are FDIC insured. Most legitimate brokerage accounts are FDIC insured. Any account that you deposit money into should be FDIC insured. Ameritrade is FDIC insured, E-Trade, Charles Shwab, etc. If you are putting money in a deposit to play prop firm, you should make sure they are FDIC insured to protect your despot, because they disappear as fast as they are made up. I've personally lost $5K to a prop firm that shut down and was not FDIC insured. If they've been around for years like you say, then that may not be an issue, but it's still a worth the extra assurance that your deposit is safe.