Vodafone’s agreement to merge its U.K. business with rival operator Three raises competition concerns, the U.K.’s antitrust authority said, creating uncertainty on a deal poised to shake up the country’s telecommunications market.

​Vodafone’s agreement to merge its U.K. business with rival operator Three raises competition concerns, the U.K.’s antitrust authority said, creating uncertainty on a deal poised to shake up the country’s telecommunications market. WSJ.com: US Business