What happened 

Shares of Clean Energy Fuels Corp (CLNE 6.15%) jumped 18.7% in March, according to data provided by S&P Global Market Intelligence, after the company reported earnings that showed some signs of improvement in the business. 

So what 

Revenue in the fourth quarter dropped 12.3% to $89.3 million, but gallons delivered increased 2.7% to 86.4 million gallons. It's the deliveries that investors were watching, partially because revenue was impacted by a lack of advanced fuel tax credits and lower revenue per gallon. 

Fuel truck driving on a highway.

Image source: Getty Images.

The fact that gallons delivered was up slightly even as management began closing 42 fueling stations was an incremental positive for the company. And with shares trading near a 52-week low to start the month, investors didn't need much positive news to push the stock higher. 

Now what 

Clean Energy Fuels may be generating slightly higher natural gas sales on a volume basis, but it's still losing money at a rapid rate. Net loss in the quarter was $28.3 million, and even on a non-GAAP basis, the loss was $9.8 million. Until those losses stop, I'll be skeptical of a turnaround for Clean Energy Fuels, but investors saw enough in the company's volume growth to take a bullish stand last month.