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.
A purchase is secured when the seller finds the bid agreeable or the buyer adjusts the bid to match the ask price quoted by the current owner of the securities or stocks. The difference between the lowest price that the seller is willing to accept and the highest that buyer is willing to pay is known as the spread.