What happened

Shares of fuel cell pioneer Plug Power (NASDAQ:PLUG) closed 4.7% higher in Tuesday trading, and just like yesterday, this appears to be a case of "pin action" -- Plug Power stock benefiting from good news that actually relates more directly to an entirely different fuel cell company.

So what

Yesterday, it was a positive analyst note concerning Ballard Power and its ability to benefit from "green energy" stimulus programs that seemed to lift Plug stock. Today, it's a big insider buy at Bloom Energy (NYSE:BE) -- former GE CEO Jeffrey Immelt laying out $1 million-plus for Bloom shares -- that seems to be getting investors optimistic about Plug stock.

Arrow angles up on a green stock chart

Image source: Getty Images.

Now what

As my fellow Fool Travis Hoium observed, Immelt sits on the Bloom Energy board of directors, and so presumably has "insider information about the company's direction" -- and perhaps about trends in the fuel cell industry as well. The fact that Immelt just spent $1 million to buy shares of Bloom therefore might not necessarily be auspicious news for Plug -- but it also might.

And today, Plug investors seem to be betting that it is.