Plug Power (NASDAQ: PLUG) spent months building up momentum, only to watch the entire move unravel in a matter of weeks. Continue »Aug. 10 is a crucial day for Plug Power as it announces its second-quarter numbers. Why Plug Power stock is falling againInvestors were buying hard into Plug Power management's turnaround promises, improving gross margins, and expanding product sales. In recent years, Plug Power has relied heavily on share sales to raise capital to keep its operations running. It was an awkward mood shift considering that Plug Power reported a bumper first quarter, with revenue rising 22 % and gross margin climbing from a negative 55% to a negative 13%.