What happened

Investors appear to be rethinking how happy they are with Plug Power's (PLUG -5.17%) Q1 "earnings update" today -- to the detriment of not only Plug's stock price but also those of other fuel cell stocks, such as Bloom Energy (BE -1.23%) and Nikola (NKLA -2.44%).

As of 11 a.m. EDT, shares of Plug stock are down 3.2%, while Bloom and Nikola are losing 4.5% each.

Cartoon character sliding down a red arrow

Image source: Getty Images.

So what

That's not entirely surprising. If you recall, investors sold off Plug stock steeply in early trading yesterday as well, only to rethink their position later in the day. After initially falling 8%, Plug's stock price quickly pulled a U-turn, ultimately closing the day up 17.6%! (Bloom and Nikola also ended Tuesday higher.)  

But it's not as if investors decided to sell Plug stock in the first place for no reason.

Sure, in the end, it seems investors were won over by Plug's assurances that it grew both sales and "gross billings" more than 60% in Q1, that both sales and gross billings will grow another 50% in Q2, and that the company is on track to fulfill its promises of generating annual gross billings of "$475 million in 2021, $750 million in 2022 and $1.7 billion in 2024," en route to capturing "a meaningful share of the $10T+ hydrogen economy."

But before reaching that conclusion, investors were surely shaken by the realization that they're going to have to wait through at least another three months to see Plug's trailing 12-month numbers show any kind of positive revenue at all. (Because Plug's trailing revenue is currently negative $100 million, even the promise of $67 million in positive Q1 revenue will leave the company showing negative trailing-12-month revenue until Q2 at the earliest. Once Q2 arrives, that number should turn positive if management succeeds in delivering the $102 million in positive revenue that it has promised.)

Now what

Today, investors must still be weighing the risk of holding a stock that shows the anomaly of negative revenue on its books for three more months. And they must weigh that risk against the hope for a positive catalyst next week, when Plug says it will restate and publish not only its 10-Q filing for Q1 2021 but also its 10-K filing for last year, containing its restated and updated earnings for the past three years.

If all goes as planned, this restatement will contain no negative news on "the Company's cash position, business operations or economics of commercial arrangements, [nor anything that might] change the fundamentals of the Company's business or growth trends" -- good news for Plug, and for everyone else involved in the fuel cell sector. On the other hand, when you consider the big price spike Plug stock got yesterday, that positive catalyst may already be baked into the stock price, leaving Plug -- and its peers -- little room to run after it materializes.