Berdy, welcome back!
From a security standpoint I would put the money in a bank.
Here is an answer to your question from the FDIC website:
"Does the FDIC insure an unpaid cashier's check, interest check, money order, or expense check issued by an insured bank?
If a depositor holds one or more of these items from an insured bank, and the insured bank fails before the item is cleared, the FDIC will add the item to any other deposits held in the same ownership category at the same insured bank. For example, an outstanding interest check payable to a depositor will be added to the depositor's other single ownership accounts, if any, and the total insured up to $250,000."