What happened

Shares of hybrid-truck powertrain maker Hyliion Holdings (HYLN 2.20%) opened sharply lower on Monday, after a Wall Street analyst cut his bank's rating on the stock.

As of 10:00 a.m. EDT, Hyliion's shares were down about 13.1% from Friday's closing price.

So what

In a new note on Monday morning, UBS analyst Steven Fisher cut his bank's rating on Hyliion to sell, from neutral, and reduced its price target for the shares to $5 from $14.

Fisher wrote that he no longer expects the company to meet revenue expectations for 2022 through 2024, which had been a key driver of its valuation. The company has taken longer than expected to hit its go-to-market milestones, undermining confidence in the management team's execution. 

A Freightliner semi truck fitted with Hyliion's hybrid powertrain.

Hyliion's products -- hybrid powertrains that can be fitted to any heavy truck -- was a good one. But with the market moving toward zero-emissions alternatives, the company may have missed its opportunity. Image source: Hyliion Holdings.

More broadly, Fisher expects a "careful" customer adoption rate as the company brings its hybrid heavy-truck powertrains to market. He noted that the macro situation — including ongoing global supply chain issues and a labor-market squeeze — will add additional challenges and delays.

To sum up, Fisher said that Hyliion's recent valuation reflects "overly optimistic" expectations for its sales ramp.

Now what

When Hyliion first made its stock market debut last year, I was impressed with the company's astute management team, its asset-light manufacturing model, and its already-established partnerships with key players in the heavy-truck ecosystem. I felt that its hybrid products were well-positioned to earn sales as trucking fleets moved to "green up" their vehicles. 

Now, the state of play has changed. On the one hand, Hyliion hasn't brought its hybrid powertrains to market as quickly as electric-vehicle investors had expected. On the other, the attention of the trucking industry has turned more toward the fully electric zero-emissions solutions that are expected to come to market over the next couple of years from major truck makers as well as new entrants like Nikola (NKLA -1.65%) and Tesla (TSLA 0.38%). 

Simply put, the window of opportunity for Hyliion's hybrid truck drivetrains may now be closing. Until and unless the company revamps its business plan, I can't disagree with Fisher's assessment.