State Street Boston Corp. is about to gain a foothold in the Midwest with a deal to buy the corporate trust business of Mercantile Bancorp.

The purchase price was not disclosed in the Wednesday deal for Mercantile's 830 accounts and $6.9 billion bond portfolio, although the St. Louis-based bank said it would post a gain worth about 8 cents a share in the fourth quarter.

Subscribe Now

Access to authoritative analysis and perspective and our data-driven report series.

14-Day Free Trial

No credit card required. Complete access to articles, breaking news and industry data.