Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Leading a broader rally in fuel cell stocks, shares of Plug Power Inc. (PLUG -7.34%) rose nearly 18% Wednesday on heavy volume after analysts initiated positive coverage on two related companies. 

So what: Specifically, analysts at Jennings Capital initiated coverage on both Ballard Power Systems (BLDP -3.06%) and its Canadian peer, Hydrogenics Corp. (HYGS). Jennings rated both stocks a buy, causing shares of Hydrogenics and Ballard Power to also jump more than 13% and 16%, respectively.
 
Ballard Power, for its part, supplies fuel cell stacks for use in Plug Power's popular GenDrive hydrogen fuel cell system, which is part of its comprehensive GenKey solution and marketed as a "superior alternative" for lead-acid batteries in all major OEM electric lift trucks.
 
Now what: First, keep in mind Plug Power isn't profitable on a trailing 12-month basis. Shares also don't look cheap, trading around 28 times last year's sales and 253 times next year's estimated earnings. However, expectations are high for growth in Plug Power's GenKey solution, with bookings doubling year over year to $80 million as of Plug Power's first-quarter report last month. Plug Power CEO Andy Marsh also stated at the time while they're targeting over $70 million in revenue this year, they expect recent investments in the business to even further "accelerate growth in the coming years." If that happens, I see no reason Plug Power won't continue rewarding patient long-term investors from here.