But that's not the same as putting small businesses out of business...
"Critics of Wal-Mart and some academic studies, particularly out of the University of Iowa, claim that Wal-Mart displaces locally-owned stores resulting in the reduction of locally-owned corporate assets and real estate, and the destruction or displacement of higher paying jobs. Other studies, including several recently from the University of Missouri, have claimed that Wal-Mart stores either do not have negative impacts or have been found to positively impact a community by effecting lower prices, increased employment, and increased establishment counts." http://en.wikipedia.org/wiki/Wal-Mart
Obviously this topic is so controversial that one may question the accuracy of the Wikipedia article...
"In September 1992, Wal-Mart founder Sam Walton contributed $3 million in scholarships to the. University of Missouri-Columbia." (www.centerforethics.org/Walmart.PDF)
And if you think that large friendly donations to educational institutions couldn't possibly result in nice warm fuzzy publications about the donor's family and interests, then you ain't been around academia (in the US anyway) for long :-) The difference between theory and practise in practise ...