"Westport is a subject of intense debate around Fooldom. On one hand, many are fans of the company's key role in natural gas vehicle conversions. On the other, it's hard to deny that Westport has grown so much that its future profitability (which isn't here yet) may already be baked in. We do have different Foolish opinions, and while I like the idea of transforming our transportation fleets to run on natural gas, Westport's ramp-up to profitability leaves it open to assault on several fronts.
While the company's partnership with Cummins (NYSE: CMI ) gives it a foot in the door in the trucking industry, Westport's engine conversions have yet to sell 1,000 units per year. Compare that to electric cars, which have broad government support, are being built by multiple automakers, and are already selling in the tens of thousands annually. Westport's scale is so small that it's difficult to award it the nat gas vehicle crown before any vehicle manufacturer makes a concerted push toward mass adoption. Most analysts already feel that Westport's meteoric rise is reaching its apex, and the company is years away from profitability.
Few stocks can keep growing as fast as Westport with no hope of profit. The stock has mocked the bears for years as it's kept making gains. But it's gone a decade without profit or positive free cash flow. By the time the red ink turns black, there may be no more gains left before competition finally gets into the game."