Wal-Mart Stores, Inc. (NYSE: WMT), which has been on a share-buying rampage in the last month or so in procuring publish shares of struggling Japanese supermarket chain Seiyu, now has another collection of shares in its pocket.

Japanese trading house Sumitomo Corp. has announced that it will sell the 6.37% stake it has in Seiyu to Wal-Mart, as the world's largest retailer almost completely concludes its quest to own every public share of Seiyu. Wal-Mart needs an international market that it owns to work as U.S. growth slows and investors start clamoring for more from the retailer. Wal-Mart shares have staggered at near the same level for over five years.

While Japan is the world's second largest market after the U.S., perhaps Wal-Mart will put a whole load of new resources into that country to ignite growth there and pacify investors who have looked down on Wal-Mart's U.S. business model in the last few years. Seiyu, though, has done horribly in the last half-decade, losing money for six straight years. Wal-Mart has a lot of work to do to right those performance figures, and it won't be easy -- even for the world's largest retail chain.