FleetCor Technologies Inc., the global provider of fuel cards and workforce payment products, has agreed to buy the electronic payment processing company Comdata Inc. from Ceridian LLC and Thomas H. Lee Partners for $3.45 billion. The deal—the biggest in FleetCor’s history—would help the company boost its expansion into virtual payment market.

Ceridian, a portfolio company of funds affiliated with Thomas H. Lee and Fidelity National Financial Inc., is the parent company of Comdata.

Georgia-based FleetCor said it would finance the acquisition by paying approximately $2.4 billion in cash to refinance Comdata’s debt and issuing about 7.3 million shares of FleetCor common stock to Ceridian.

Alston & Bird advised FleetCor on the deal while Weil, Gotshal & Manges acted as legal counsel to Comdata, Ceridian, Thomas H. Lee Partners and Fidelity National Financial Inc.

The deal is subject to customary closing conditions, including antitrust and other government approvals related to Comdata’s money transmitter license business. The transaction is expected to be completed in the end of December 2014.

Comdata, specializing in business-to-business e-payment services, provides fleet, virtual card and gift card solutions to over 20,000 customers and facilitates over $54 billion in payments annually.

“Comdata’s virtual payments business will add a completely new growth leg to FleetCor,” said Ron Clarke, chairman and chief executive officer of FleetCor, in a statement. “We believe that the combination will result in significant synergies as we implement our operating disciplines to their portfolio of businesses.”

Acquired by Ceridian for $900 million in 2005, Comdata was taken over by Thomas H. Lee and Fidelity National Financial as part of their $5.3 billion buy of Ceridian in 2007. Ceridian and Comdata were separated last year.

FleetCor, with a market capitalization of about $11 billion, has been growing quickly through its active acquisitions. It has completed four deals in the past 12 months, acquiring VB Servicos Comercio Administracao Ltd. and DB Trans S/A together—both of which provide transportation cards and prepaid toll, fuel and payroll card programs for transportation in Brazil—for $300 million. It also acquired NexTraq, which offers telematics solutions to small and medium-sized businesses, and U.K.-based cloud business Epyx for an undisclosed sum.

According to FleetCor’s second-quarter financial results issued on July 31, the company has witnessed strong organic growth benefiting from previous acquisitions.

Alston & Bird provided legal counsel to FleetCor. The team was led by corporate partner Chris Baugher, with assistance from corporate partner Justin Howard, tax partners Sam Kaywood and Blake MacKay and litigation partner Valarie Williams. Senior associates Scott Kitchens and Spencer Robinson were also on the team.

Weil advised Comdata Inc., Ceridian, Thomas H. Lee Partners and Fidelity National Financial Inc. on the transaction. The team consisted of corporate partner Michael Aiello, tax partners Kenneth Heitner and Chayim Neubort, benefits partner Paul Wessel, capital markets partners Todd Chandler and Alexander Lynch, banking and finance partner Allison Liff, structured finance partner John Dedyo, technology and IP transactions partner Michael Epstein, antitrust partners Steven Newborn and Laura Wilkinson and litigation partner Randi Singer.

Counsel Steven Margolis and associates Matthew Goulding, Benton Lewis, Cheri Bessellieu, Barbra Broudy, Garrett Charon, Caroline Geige, Joshua Gelfand, Joey Juhn, Suzanne Lee, Eugene Ng, Sanil Padiyedathu, Kaj Rozga, Joseph Santo and Janell Wise also advised.

Thomas H. Lee Partners and Fidelity National Financial Inc. are both long-standing clients of Weil. In July, Weil advised Acosta Sales & Marketing, a portfolio company of Thomas H. Lee, in the $5 billion sale of Thomas H. Lee’s equity investment in Acosta to The Carlyle Group.