Shares of Clean Energy Fuels Corp. continued to slide Tuesday, a day after the Seal Beach-based company reported mixed first-quarter financial results.

Investors sent shares down 9.5% in early afternoon trading, giving the stock a market value of about $1.38 billion.

The natural gas station builder and operator reported quarterly revenue of $76.3 million, up nearly 13% and missing Wall Street expectations.

Analysts on average had expected sales of $81.6 million.

The company reported an adjusted loss of $13.7 million, better than Wall Street’s consensus of an adjusted loss of $15.4 million.

Clean Energy delivered 43.7 million gallons of natural gas in the March quarter, up 23% from a year earlier.

The company has yet to clear earnings hurdles amid a push to build and expand what Clean Energy is calling “America’s Natural Gas Highway.”

Major transportation arteries in California, Texas and the Midwest are expected to have natural gas stations spread out every 250 miles or so when the multiyear project concludes.

It is targeting the largest segment of the market: heavy-duty haulers that consume some $30 billion of fuel annually.

That dwarfs the public sector and waste management industries combined.

Legendary oilman and corporate raider T. Boone Pickens started Clean Energy as a tiny part of his Dallas-based Mesa Petroleum in the late 1980s. He split it off in the late 1990s.

Clean Energy shares often see wide fluctuations based on macroeconomic affects and may have dropped further Tuesday as part of the down trading session today.