Westport Innovations (Nasdaq: WPRT) probably wouldn't make any sane person's short list of stocks to own in an economic downturn. And for good reason: Westport is an alternative energy company and -- more important -- a chronic money loser. Nonetheless, as the Dow hovers near a 52-week low, Westport is near not only a 52-week high, but an all-time high. So what gives?

Recently, Westport and Royal Dutch Shell (NYSE: RDS-B) announced a joint marketing agreement intended to tout liquefied natural gas as a viable alternative transportation fuel. Westport's stock spiked roughly 20% on the news, which was not a big surprise considering the agreement signals big oil may be ready to jump on the natural gas bandwagon.

However, there was no significant "sell the news" moment. Westport surged an additional 10% since the announcement nearly three weeks ago. This is especially surprising considering the Dow just experienced its worst week since 2008. Could something else be driving shares higher?

A Congressional committee recently held hearings regarding the NATGAS Act. Congressional action on the nat-gas-friendly legislation has served as the main catalyst for Westport in the past.

Upon introduction of the bill last spring, shares of Westport Innovations surged nearly 60%. The other nat-gas vehicle stocks, Clean Energy Fuels (Nasdaq: CLNE) and Fuel Systems Solutions (Nasdaq: FSYS), surged as well.

But if the recent Congressional action is driving Westport's shares higher, one would expect the other nat-gas transportation stocks to participate as well. This has not been the case. Fuels Systems Solutions and Clean Energy Fuels have been clobbered during the recent market downturn. This leads to another possible culprit for Westport's surprising share price ascent: a buyout.

Westport is an attractive takeover target for many reasons. The company is a major player with proprietary technology in a growth industry. Westport has also signed some lucrative contracts with some big names in the transportation industry. Furthermore, Westport has made major strides in cleaning up its balance sheet over the last year, an exercise common for a company seeking a buyer.

The bottom line
There may be more than meets the eye in Westport's recent market-defying move higher. The market could be sniffing out a potential takeover, making Westport an attractive speculation stock.