SOUTH PORTLAND – WEX Inc. posted higher first-quarter profits Wednesday and announced a successor for Chairman and CEO Michael Dubyak.

Melissa Smith, 44, has been appointed president of WEX, a credit-card processing company. She will become CEO and president on Jan. 1 and take a seat on the company’s board of directors.

Smith joined WEX in 1997 and most recently was the company’s president for the Americas.

Dubyak, 62, will remain chairman and CEO during the transition, then move to the new position of executive chairman of the board, the company said.

For the first quarter of this year, the company posted adjusted net income of $38.3 million, 98 cents a share, compared with $35.6 million, 91 cents a share, in the same period a year ago.

First-quarter revenues increased 18 percent, to $165.4 million, from $140.1 million a year ago.

For the full year 2013, the company cut its outlook, citing a decline in fuel prices, which affects its fleet card division. Foreign exchange rates and the potential impact from an industry-wide payment card settlement also affected the forecast.

For the full year, the company expects revenues to be in the range of $716 million to $736 million, compared with previous estimates in the range of $721 million to $741 million.

Adjusted net income will be in the range of $4.20 to $4.35 a share, compared with a previous projection of $4.30 to $4.50 a share.

WEX’s stock fell sharply because the company cut its outlook. The stock closed Wednesday at $67.91 per share, down $7.87, 10.4 percent.

“We feel very confident about our accomplishments of the first quarter,” Dubyak said in a telephone interview. “Unfortunately, we have to take down guidance, which no one likes to do, but we can’t control factors like the credit card settlement and fuel prices.”

Dubyak said the company will continue to seek acquisitions to supplement its business. WEX has $1.4 billion available from a bond offering that it can use to expand the business.

WEX said it had no update on the potential move from South Portland to another Maine site.

Jessica Hall can be contacted at 791-6316 or at:

jhall@pressherald.com