THE SEIYU is one of Japan's top retailers, SEIYU runs about 370 stores, including supermarkets and general merchandise stores. Merchandise includes food, apparel, and household goods (under international brands or SEIYU's own brands).

Company flags include SEIYU, Sunny, and SSV. (supermarkets) and Livin (department stores).

According to BusinessWeek Online, Walmart, the giant American retailer, bought a 37 percent stake in Seiyu in 2002, and according to a company press release, in late 2005 Walmart acquired a majority stake in the company which it has since increased to 95% ownership,  and 100% ownership in 2008