Final answer:
The futures markets use a process called mark-to-the-market to calculate daily gains and losses, which are then adjusted in the trader's account.
Step-by-step explanation:
In the futures markets, the process by which gains and losses in a contract's value are calculated daily and added to or subtracted from the trader's account is called mark-to-the-market. This mechanism is essential to the futures trading system, ensuring that all positions are revaluated at the end of each trading day to reflect current market values. It is different from a time deposit, where money is left in a bank for a certain period to earn interest, or a T-account, which is a type of balance sheet. Also, it should not be confused with transaction costs, which are expenses associated with finding a lender or borrower.