How do futures contracts work? Consider the example of a farmer hedging by entering into a futures contract to sell October corn at $3 a bushel. The first day the price rises by $0.02 so that the value of the position loses $100 (the two cents times the size of the contract, which is 5000 bushels). The clearing house debits $100 from the farmer’s margin account. If the new amount in the account does not fall below the maintenance level, then no further action is required. If the loss were to reduce the level in the account to below the maintenance level, then the farmer would be required to add resources to the account (cash or Treasury securities) until it reached the higher initial margin level. If the price moves in favor of the farmer, then the clearing house credits the farmer’s margin account and the farmer is allowed to withdraw excess funds from the margin account. This process of adjusting the margin account to the daily changes in futures prices is known as marking the position to the market value, or “mark to market” for short.