What happened 

Shares of fuel cell company Bloom Energy (BE 6.04%) jumped as much as 22.7% in trading on Friday after getting a big upgrade from an analyst. The pop faded in the afternoon, but shares were still up 18% at 1:40 p.m. EDT today. 

So what

Morgan Stanley was the cause of today's jump, giving the renewable energy stock an overweight rating and a $21 to $23 price target. That represents a nearly 30% upside at the midpoint, even after today's move in the stock. 

Dice flipping to spelling hydrogen fuel.

Image source: Getty Images.

Analyst upgrades and downgrades can move stocks in the short term, but it's the fundamentals that will ultimately be more important for long-term investors. I like where Bloom Energy's business is going with a transition to renewable hydrogen, from natural gas, and an industrial electrolyzer hitting the market. But it'll be a few years before we know if the strategy works, and that's what investors will want to be watching. 

Now what

At the end of the day, this isn't a time to change your investment thesis on a stock like Bloom Energy. If you liked the company yesterday, that shouldn't change. But it is nice to get validation from analysts, and that's really all bullish investors are getting today. Once the euphoria from today fades, I'll be focused on third-quarter results when they're released this fall. That's where the rubber really meets the road.