What's Really Motivating Plug Power Inc. (PLUG) Call Buyers?

Plug Power Inc (NASDAQ:PLUG) is bucking the broad-market trend lower, up 12.3% at $2.51. The energy stock is getting a boost from the company's impressive current-quarter shipments of fuel cells and hydrogen infrastructure equipment, which have paved the way for record single-quarter revenue. This could be good news for option bulls, who have been buying to open calls at a breakneck pace of late.

Specifically, during the past 10 weeks at the International Securities Exchange (ISE), Chicago Board Options Exchange (CBOE), and NASDAQ OMX PHLX (PHLX), speculators have bought to open nearly 11 PLUG calls for every put. The corresponding call/put volume ratio of 10.87 sits a mere 2 percentage points from a 12-month high. Today, in fact, buy-to-open activity is detected at the July and weekly 7/24 2.50-strike calls.

Echoing this, the stock's Schaeffer's put/call open interest ratio (SOIR) checks in at 0.50. In other words, call open interest doubles put open interest, among PLUG options set to expire in the next three months.

However, recent call buyers -- especially at out-of-the-money strikes -- aren't necessarily bullish. After all, 18.4% of PLUG's float is sold short, representing nearly three weeks' worth of trading activity, at typical volumes. In other words, some of the recent call buyers may simply be short sellers hedging their downside bets.

Adding credence to this theory is Plug Power Inc's (NASDAQ:PLUG) long-term technical track record. Heading into today's session, the stock had lost half of its value year-over-year, touching an annual low of $2.17 just yesterday.