# Margin accounts and futures delivery

I'm trying to understand the market mechanics of futures with delivery. For sake of example, assume 0 interest rates and no cost of carry, and that I bought a futures contract on Jan 1 with Feb 1 expiry for \$100, on some fictional commodity. On Feb 1 the spot price proves to be \$150. I put in \$20 in the margin account. So, am I correct in saying that

• my margin account will have increased by \$50
• I pay \$100 to the clearing house and am delivered the commodity
• I can sell the commodity in the spot market for \$150, thus pocketing \$150-\$100 = \$50 off of this transaction and the last
• I made \$100 on this trade, 50 from the margin acct and 50 from the previous bullet point??

Basically to me it seems like I made 50 dollars twice, once through the margin account, and once via the spot market and futures expiry. Obviously something is wrong here. My question is:

Does the futures price moving from 100 to 150 mean I can make 50+50=100? Or is my logic wrong somewhere?

• If you buy something for \$100 and sell it for \$150, you make \$50 which is a 50% profit. If you put up less then \$100 to buy it (margin), your ROI is higher. Mar 26, 2018 at 11:58