All it takes to make a penny stock double in price is a good, shotgun, bit of spam. "One month ago, our firm listed XYZ as a 'Strong Buy'. Last week it went from $0.03 to $0.07. We are are forecasting it will reach $0.75, a ten fold increase by the end of the month." A bunch of suckers buy, and the price hits a quarter, and the spammer sells his 832,715,025 shares and triples his money.