The price of Wright Express stock dipped more than 20 percent in morning trading on Wednesday after the company released third-quarter earnings.

"We met the low end of our guidance for revenue and adjusted net income this quarter, but the challenges were greater than we expected," Wright Express President Michael Dubyak said in a statement. "The ongoing slowdown in fleet fueling activity accelerated as economic conditions deteriorated in August and September."

Wright Express is a South Portland company that provides payment processing and information management to the vehicle-fleet industry.

On an adjusted basis, the company reported a third-quarter profit of $21.8 million, compared with $22.3 million for the same period last year.

On a per-share basis, adjusted earnings were 55 cents a share for the three months ending Sept. 30, the same as last year.

Total revenue increased 24 percent to $108.5 million from $87.7 million for the third quarter of 2007.

Wright Express is one of the area's largest employers with more than 700 workers.

Adjusted earnings exclude some one-time items, such as paper losses or gains on fuel-price derivatives that Wright Express uses to offset the earnings impact of wide swings in gasoline prices.

Looking forward, company officials announced that they now expect adjusted profit for the entire year in the range of $74 million to $76 milion, or $1.86 to $1.91 per share. Annual revenue is expected in the range of $394 million to $400 million, based on the assumption of an average retail fuel price of $3.54 per gallon.

The volatile gas prices this year have been a double-edged sword for the company. The company benefits from higher fuel prices because it gets more revenue per transaction through its percentage-based payment processing fee, which accounts for about 70 percent of the company's revenue. But high prices mean customers are employing fewer drivers and limiting fuel consumption.