BENTONVILLE, Ark. -- At Wal-Mart Stores here, small may be preferable to large when it comes to supercenters. Wal-Mart plans to concentrate more on expanding its 136,000-square-foot supercenter prototype in 1997 and 1998 than on the 188,000- or
167,000-square-foot models that make up most of its existing 239 supercenters, according to Nick White, executive vice president for supercenters.
Only 25 of those stores fall into the 136,000-square-foot size. White said Wal-Mart execu