Major discount store operator Trial Holdings Inc. said on March 5 it will acquire supermarket company Seiyu Co. for about 380 billion yen ($2.5 billion) and make it a wholly owned subsidiary.

KKR and Walmart have agreed to sell Seiyu for about $2.5 billion, ending foreign ownership of one of Japan’s most well-known supermarket operators. The U.S. investment company plans to sell its ...