Fast-growing Wex Inc. in South Portland boosted its revenue by 41 percent and net income by 26 percent in the first quarter, thanks in part to a rise in fuel prices, the company reported Thursday.

Wex, a provider of corporate payment services, reported revenue of $291.4 million for the quarter, compared with $205.9 million for the first quarter of 2016. The company reported net income of $52.9 million, or $1.23 per share, up from 98 cents per share a year earlier.

“It was a really good start to the year,” Wex President and CEO Melissa Smith said in an interview Thursday.

Wex provides fuel payment cards and payment-processing services to companies and government organizations that operate fleets of trucks and other vehicles. It also provides payment processing to online travel-booking services and health care providers.

During the quarter, higher fuel prices positively affected Wex revenue by $15.4 million when compared with the first quarter of 2016, the company said in a news release.

Total fuel transactions processed by Wex increased 24 percent from the first quarter of 2016 to 123.9 million, and the average customer expenditure per payment-processing transaction increased by 42 percent. Wex generates revenue by taking a small percentage of the total fuel transaction cost.

Growth by acquisition also helped Wex boost its revenue for the quarter.

Wex has grown significantly in recent years by acquiring competitors, signing new contracts and expanding its business into new areas.

In July 2016, the company closed on its largest acquisition to date, the purchase of Nashville, Tennessee-based competitor Electronic Funds Source LLC for nearly $1.5 billion. The increased revenue from that transaction helped push Wex’s 2016 revenue up to $1.02 billion, a 19.2 percent increase from $854.6 million in 2015. It was the first time the company’s annual revenue topped $1 billion.

Smith said about 13 percent of the company’s year-over-year growth in the first quarter was “organic” growth not attributable to fuel price increases or acquisitions. That growth came from new and existing customers.

“We’re not standing still,” she said. “We’re a billion and growing.”

Wex has a workforce of more than 2,700 employees worldwide, including more than 800 in South Portland. A publicly held company, it trades on the New York Stock Exchange under the symbol WEX.