That's not how futures work. I am short from 9600 with my future expiring in a few weeks, every tick is 5 dollars deposited or 5 dollars removed on settlement time(daily). There is no "investment" besides linking it to a margin account. For example, it looks like it will close around 9100. I will have credited to my account $2500 dollars since I am short exactly 1 future, with zero "investment" besides the $10 bucks or whatever the contract cost.