As natural gas becomes a more and more viable energy option  for the U.S., companies associated with gas have been the subject of much  discussion . One of those companies at the forefront of the movement is Westport Innovations (NASDAQ:WPRT).

The Canadian company is a leader in designing engines that can run solely on natural gas. Westport has teamed up with car, truck, railroad, and even heavy-machinery companies to form joint ventures to provide engines that can run on cheaper, cleaner natural gas.

A big spike
Over the past two trading days, shares of Westport have risen by as much as 12.5%,  despite no substantial news from the company.  

Instead, it seems that some within the industry are hearing whispers that Westport may be a buyout candidate . The name mentioned more than any other as a potential buyer is engine maker Cummins (NYSE:CMI).

A purchase by Cummins would actually make quite a lot of sense, as the two companies have been working together for years on their Cummins Westport joint venture, which focuses on designing and manufacturing natural gas engines for long-haul trucks.

One of the biggest threats that Westport faces is the fact that it only designs -- and does not manufacture -- the engines used by customers. If any manufacturer were to develop its own method of building natural gas engines, Westport could be left out in the cold.

Cummins has made no secret of the fact that it will be designing its own separate 15-liter natural gas engine for truckers while maintaining its joint venture with Westport. A purchase of Westport could accelerate Cummins' ambitions.

That being said, speculation is just that: speculation. JPMorgan has already come out and said that any takeover by Cummins is "highly unlikely."