Aeon Co., Japan's second-biggest retailer, increased second-quarter profit 55 percent as net income rose to ¥15.8 billion in the three months to Aug. 20, from ¥10.2 billion a year earlier.

Second-quarter figures were calculated by subtracting first-quarter earnings from the ¥23.8 billion first-half profit the retailer reported Thursday.

The company, based in Chiba Prefecture, said it plans to spend up to ¥70 billion buying back its stock.

Aeon, which owns chains including Jusco discount outlets and Ministop convenience stores, is buying stakes in rivals in Japan to lower costs and expanding overseas as it seeks growth outside a market where retail sales have fallen for nine of the past 11 months.

The company last month increased its stake in supermarket rival Maruetsu Inc. to 31.9 percent. The investment, which may lead to a takeover, will make it easier for the companies to negotiate lower prices with suppliers for food, clothing and other goods.

Revenue in the half rose 7.7 percent to ¥2.53 trillion on rising sales at its supermarkets and specialty stores.

Aeon, which bought Carrefour SA's Japanese stores in 2005, operates more than 1,300 supermarkets and general merchandise stores.

It competes with Wal-Mart Stores Inc.'s Seiyu Ltd., which is projecting its fifth consecutive annual loss this year, in a grocery market whose sales have fallen 19 months in a row.