A steep decline in fuel prices cut into quarterly operating profits for WEX Inc., despite an increase in the volume of its payment transactions, the company reported Wednesday.

Still, the South Portland-based company’s successful efforts to hedge against those losses through investments resulted in adjusted net income for the first quarter that beat analyst expectations by a considerable margin.

WEX, which provides fuel, travel and health care payment-processing services, reported total revenue of $202.3 million for the first quarter, up 11 percent from $182.1 million for the first quarter of 2014.

Its net operating income was down considerably from the same period a year earlier. WEX reported quarterly net income of $22.3 million or $0.57 per share, a 39 percent drop from $36.5 million or $0.93 per share in the first quarter of 2014.

But after adjusting for one-time gains and losses associated with the company’s strategy of hedging against fluctuations in fuel prices, net income was much higher at $1.10 per share. That figure is a slight improvement over its $1.06 per share adjusted net income for the first quarter of 2014, and about 10 percent higher than most analysts expected, according to a survey by Zacks Investment Research.

“We actually did increase earnings growth” after the adjustments, said company President and CEO Melissa Smith.

The average number of vehicles serviced by WEX worldwide was roughly 9.3 million for the quarter, an increase of 19 percent from a year earlier, and total fuel transactions processed increased 6 percent from the year-ago quarter to 98.1 million. Payment-processing transactions also increased 12 percent to 81.9 million.

However, the average U.S. retail fuel price decreased 29 percent to $2.57 per gallon, compared with $3.64 per gallon a year earlier, WEX said.

Smith said the company’s revenue would have increased about 26 percent, rather than 11 percent, had fuel prices remained at $3.64 per gallon.

Still, she said WEX has dramatically reduced its exposure to fluctuating fuel prices by diversifying into the travel and health care industries. Only about 40 percent of the company’s business is sensitive to fuel price fluctuations, Smith said.

WEX also hedges against losses related to fuel prices by buying “put options” – the equivalent of insurance policies for investors – against declines in the price of fuel.

“I am pleased with the growth we demonstrated across our geographies and verticals this quarter, despite the backdrop of ongoing fuel price headwinds,” Smith said. “We delivered top- and bottom-line results that exceeded our expectations.”

WEX is a publicly held company that trades on the New York Stock Exchange under the symbol WEX.