Convenience store chain FamilyMart Co. and its top shareholder, Itochu Corp., are in the final stages of negotiations over acquiring smaller rival am/pm Japan Co., sources said Thursday.

The deal would give No. 3 FamilyMart and No. 7 am/pm Japan a combined 8,700 stores in Japan, compared with about 9,700 for second-ranked Lawson Inc. Industry leader Seven-Eleven Japan Co. has nearly 12,500 outlets.

Under the plan, FamilyMart and Itochu would acquire all shares from am/pm's parent company, Rex Holdings Co., in a transaction expected to be worth around ¥10 billion, with all am/pm stores likely to be rebranded FamilyMart, the sources said.