Bank statements. One sort of financial record is a bank statement. Your bank will regularly send a statement containing information showing income (credits) and outgoings (debits) on your bank account.
They're synonyms. Gain is the most general. Attain usually means to reach a goal or milestone (he attained the rank of captain). Obtain usually implies careful planning or some effort to get to the thing or goal. But they have probably something like 80% overlap in meaning.
The difference between holder and holder in due course are: Holder means any person entitled in his own name to the possession of the negotiable instrument and to recover or receive the amount due thereon from the parties thereto.