This merger should create the largest midcap bank in the Midwest, according to TCF.

WAYZATA, Minn. — Two Midwest-based banks plan to merge to create a bank with $45 billion in assets that will be based in Detroit.

Detroit-based Chemical Financial Corp. and Wayzata, Minnesota-based TCF Financial Corp. announced Monday the signing of an agreement under which the companies will combine in what they described as an all-stock "merger of equals."

Plans call for TCF to merge into Chemical Financial, and the combined holding company and bank will operate under the TCF name and brand. The company will have more than 500 branches in nine states, including "significant operation centers" in Minneapolis and Chicago.

This merger should create the largest midcap bank in the Midwest, according to TCF. The new bank will have more than 500 branches across nine states.

The deal is subject to regulatory approval.

Chemical Financial, the holding company for Chemical Bank, last year moved its headquarters from Midland, Michigan, to Detroit and announced plans for a 20-story building downtown.