You bought index futures contract at 1,000 and were required to put up initial margin of $8,000. The value of the contract is 1,000 times the $100 multiple, or $100,000. The next three days, the contract's settlement price was at theses levels:

day 1: 990

day 2: 965

day 3: 940

Calculate the value of your margin account on each day.

If the maintenance for the contract is $4,000, how much variation margin did the exchange require you to put up at the end of the thurd day?