What happened

While the Dow Jones Industrial Average was up marginally on Tuesday afternoon and the S&P 500 was close to flat, shares of fuel cell specialist Plug Power (PLUG 10.20%) were moving lower. After having been down by as much as 5% earlier in the session, Plug Power was off by 2.7% as of 1:49 p.m. ET.

While some might have expected that the company's shares would rise in response to news that it had secured a deal with an international oil company, it seems that investors have questions about that agreement. In addition, news from a renewable energy sector peer may also have had investors looking to trim or close their positions in Plug Power on Tuesday.

So what

Plug Power announced Tuesday that it had received an order from Irving Oil, an energy company with downstream assets in North America and Europe, for a 5-megawatt electrolyzer. Irving Oil will use the electrolyzer to produce and distribute hydrogen at its refinery in Saint John, New Brunswick, Canada.

While management lauded the deal as an indication of how its hydrogen products are in demand, investors appeared skeptical about how significantly it will benefit the company. Financial details were missing from the company's press release, likely leading investors to surmise that the deal will do little to move the needle for Plug Power.

In addition, Plug Power bears may be active Tuesday in response to Canoo's (GOEV -0.28%) announcement of an order from Walmart (WMT 0.26%) for 4,500 electric delivery vans, with an option to buy more. Plug Power has been a longtime partner of Walmart, and investors may be interpreting Canoo's deal as a sign that Plug Power's chances for success in the electric vehicle delivery market are lower than management believes.

Now what

Plug Power often publicizes the new orders it receives for its fuel cell products, yet it rarely provides financial terms of those deals when it does so. This, unsurprisingly, leaves investors suspicious. Compound that with the fact that Canoo received a notably large order from Walmart, and it's little wonder that Plug Power's stock is in the red Tuesday.