FamilyMart Co. and Uny Group Holdings Co. merged on Thursday to create the nation's second-largest convenience store chain after Seven-Eleven Japan Co.

The formation of FamilyMart Uny Holdings Co. marks consolidation in an industry where retailers face intense competition to boost sales in a sputtering economy with a declining population that is expected to shrink further.

Japan's three major retailers are Aeon Co., Seven & i Holdings Co., the parent of Seven-Eleven Japan, and FamilyMart Uny.

FamilyMart Uny will focus on the twin businesses of convenience stores and supermarkets. Uny has had a business stronghold in areas around Aichi Prefecture.

As most of the 6,250 Circle K Sunkus stores operated by Uny are set to be renamed FamilyMart, the total run by the holding company now stands at around 17,000 in Japan. Industry leader Seven-Eleven Japan has around 18,800 stores.

On Thursday, three Circle K Sunkus convenience stores in Tokyo, Nagoya, and Osaka were converted to FamilyMart.

FamilyMart and Uny struck an agreement in October last year to merge and set up the holding company, with FamilyMart as the surviving entity.