 At the time of the merger, the new company had 720 full-service banking offices in Ohio, Wisconsin, Kentucky, Illinois, Indiana, Iowa, Minnesota, Tennessee and Arizona.Just five months later the newly combined Firstar announced in May 1999 the pending acquisition of St. Louis-based Mercantile Bancorporation for $10.6 billion in stock.At the time of the announcement, Mercantile had nearly 500 banking locations throughout Missouri, Iowa, Kansas, Illinois, Arkansas and Kentucky while Firstar had approximately 715 full-service banking offices in Ohio, Wisconsin, Kentucky, Illinois, Indiana, Iowa, Minnesota, Tennessee and Arizona.