Math For Dummies. If a stock is 2.20 and goes down to 1.10 then that is a 100% drop. If a stock is 2.20 and goes up to 4.40 then that is a 100% increase. I'm my own trader, if I happen to agree with others who are short so be it. I believe that all the longs on here are individual's and also fools. Enjoy the ride down!