The deal is the biggest in the electronic payments industry, underlining the growing popularity of digital payments for online and store sales versus cash.

U.S. financial services provider FIS produces software for banks and asset managers as well as its financial services outsourcing business. Worldpay is a major player in card payments. FIS sought EU clearance on May 28.

The EU competition enforcer can either clear the deal with or without conditions after its preliminary review or it can open a full-scale investigation if it has serious concerns.

(Reporting by Foo Yun Chee; editing by Jason Neely)