12. On September 1, you sold 100 S&P 500 futures contracts at 1,800 with multiples of $250, expiration date in three months, and an initial margin of 10%. After that date, the index fell steadily, and you were not required to post any additional margin, but you also did not withdraw any of the cash profits you were earning. On November 1, the futures price of the contract was 1,620, and you reversed your position by buying 100 contracts.

a. How much money did you make (ignoring taxes and commissions)?

b. What was the rate of return on your invested funds?

c. In those two months, the S&P 500 futures price fell 10%. Explain why your rate of return is so much higher than this level.