Plug Power Inc. Officials explained Monday that the 39 million shares of the fuel cell manufacturer’s common stock, registered last week by Plug’s Russian investors, Smart Hydrogen Inc., can’t just be sold “willy nilly.”

“For 24 months they can’t sell it. They aren’t pulling out. Nothing has changed. There is no impact on the company,” Plug Power Director of Product Marketing Eoin Connolly said.

Connolly said some readers of Plug Power’s document filing with the U.S. Securities and Exchange Commission last week, detailing the changes to Smart Hydrogen’s stock holdings, may not have noticed the restrictions placed on the future sale of the stock. He said Smart Hydrogen’s investment in Plug Power in 2006 was contingent upon the company holding preferred stock for a period before it converted to common stock last week, 18 months after the initial investment.

“Part of us agreeing to them investing in the company [was that] lock-up period,” he said.

Prior to the conversion of the preferred stock into common stock last week, Smart Hydrogen was restricted from selling any of its equity in the company. Going forward for the next two years, Smart Hydrogen can’t sell to any person who would then become a 5 percent owner of Plug Power and Plug Power itself has the right of first offer on any sale of Smart Hydrogen’s stock. For the next 5 years Smart Hydrogen is also restricted from selling its stock to a Plug Power competitor.