Answer:
The Walmart Effect is a term used to refer to the economic impact felt by local businesses when a large company like Walmart (WMT) opens a location in the area. The Walmart Effect usually manifests itself by forcing smaller retail firms out of business and reducing wages for competitors' employees.
or in book way:
The Wal-Mart Effect is a 2006 book by business journalist Charles Fishman, a senior editor at Fast Company magazine, which describes local and global economic effects attributable to the retail chain Walmart.