Plug Power Inc (NASDAQ:PLUG) remains a highly speculative play. That’s clearly reflected in the stock’s volatility. Shares of the fuel cell company have risen from the lows of $1.55 to as high as $11 before falling to around $4.75. Many are shorting the stock, believing that the stock is extremely overvalued and the fuel cell technology has no long-term future. Another group of investors believes that the company has a bright future as demand for the renewable energy grows.

Plug Power

Whitney Tilson, Kerrisdale shorting Plug Power

Amid one after another positive catalysts, Plug Power has seen a significant decline in short interest in June. According to Nasdaq, short interest has declined from 35.14 million on May 30 to 30.92 million on June 13, the latest settlement date for which data is available. That reflects a 12% decline in short interest in just two weeks. The average daily trading volume has also fallen considerably from 16.1 million to 7.96 million in the same period. Based on the daily trading volume of 7.96 million, it would take short sellers 3.88 days to cover their positions.

About 19.2% of the Latham, New York-based company’s shares are held short. Some of the most prominent firms shorting the stock are Kerrisdale Capital and Whitney Tilson’s Kase Capital. Tilson says valuations in the fuel cell industry are foolish. Kase Capital is also shorting Plug Power peers such as FuelCell Energy Inc (NASDAQ:FCEL) and Ballard Power Systems Inc. (NASDAQ:BLDP). Whitney Tilson believes these stocks are worth no more than a dollar.

Plug Power successfully demonstrates GSE fuel cells

On Friday, Plug Power shares rallied about 5% amid speculations that FedEx Corporation (NYSE:FDX) could purchase its fuel cells. Plug Power is trying to go beyond forklifts, and power ground support equipment at airports. Last week, the company successfully demonstrated its hydrogen fuel cell beta units that would power GSEs at airports such as baggage loaders, aircraft tuggers and auxiliary power units.

Plug Power has already signed a deal with FedEx to make fuel cell range extenders for 20 FedEx Express delivery trucks. Now Plug Power also aims to supply 15 GSE fuel cells to FedEx by the end of this year.

Plug Power shares fell 1.06% to $4.68 on Monday close.