What happened

After an incredible run higher over the past six months, fuel cell stocks came crashing to earth today along with the rest of the stock market. FuelCell Energy (FCEL -7.60%) shares fell as much as 18.7%, Ballard Power Systems (BLDP -4.80%) dropped 17%, and Plug Power (PLUG -4.93%) plunged 12.6% at its low. Shares of the stocks were down 7.1%, 12.4%, and 5.7% respectively at 2:55 p.m. EST, and it doesn't seem like any sort of recovery is in the cards today.

So what

When markets are going up, volatility can work in fuel cell investors' favor. But when markets go down, volatility can hit stocks hard. And that's exactly what's happening with fuel cell stocks today. These three stocks have run up fast and furiously over the past few months, and with the market down between 2% and 3%, they're outpacing the market in falling back to earth.

FCEL Chart

FCEL data by YCharts.

Fundamentally, nothing has changed today, but investors worried about SARS-CoV-2, the coronavirus causing the COVID-19 outbreak, think it may take a bite out of economic growth worldwide. And that could put a damper on fuel cell demand if the downturn lasts for a while.

Let's take these growth stocks one by one and see where their risk lies. FuelCell Energy supplies commercial buildings and utilities with fuel cells, and a short-term virus-driven economic hiccup isn't likely to hurt its demand. Ballard makes fuel cell technology for industries like materials handling, trucks, and rail operations; if the economy goes into recession, orders may be impacted, but that'll be the case for any company. Plug Power is another material-handling company, and with customers like distributors and warehouse operators, there would be a pretty big lag before any fundamental slump takes place.

Ultimately, the core business of building and selling fuel cells shouldn't be impacted too heavily, given what we know today.

The outline of a battery made of leaves, with the symbol for hydrogen in the background

Image source: Getty Images.

Now what

The bigger question for investors today is whether or not these fuel cell stocks are worth buying on the dip. And I'm more skeptical when it comes to that question. All three companies are reporting large annual losses, and they're also using shares to fund operations, constantly diluting shareholders.

FCEL Net Income (TTM) Chart

FCEL Net Income (TTM) data by YCharts.

Until these companies are on solid financial footing, I won't see this as a buying opportunity. I think the risk investors are seeing may be overblown short-term, but that doesn't make any of these stocks a buy today.