Chemical Financial, the holding company of Chemical Bank, has completed the previously announced acquisition of OAK Financial, the holding company of Byron Bank.

Subsequent to the closing, Chemical has $5.1bn in assets, $3.6bn in loans and $4.2bn in deposits in 144 banking offices across 32 counties in Michigan’s Lower Peninsula.

Byron Bank operates 14 banking offices in Kent, Ottawa and Allegan counties in Michigan, and at March 31, 2010 had $812m in assets, $687m in loans and $691m in deposits.

Current Byron Bank locations will continue to operate under the Byron Bank name until late July 2010, at which time the conversion to Chemical Bank’s data processing platform will be completed. After the conversion, all locations will operate under the Chemical Bank name.

Chemical was advised by the investment banking firm of Keefe, Bruyette & Woods and the law firm of Warner Norcross & Judd. OAK was advised by the investment banking firm of Donnelly Penman & Partners and the law firm of Varnum.

David Ramaker, chairman, CEO and president of Chemical, said: “This merger clearly enhances our competitive position, branch distribution system and overall capabilities in the important grand rapids market. Customers of both institutions across Michigan will benefit from access to new product and service offerings as a result of the merger.”