MidWestOne Financial Group is a bank holding company headquartered in Iowa City, Iowa. The bank operates 57 branches. It is the 3rd largest bank headquartered in Iowa. It operates in Iowa, Minnesota, Wisconsin, Colorado, and Florida. The bank was formed in 1934 as the Iowa State Bank & Trust Company in Iowa City, Iowa by Ben S. Summerwill. In 1984, ISB Financial Corp. was established as a closely held bank holding company for Iowa State Bank & Trust Company. In March 2008, ISB Financial Corp. merged with MidWestOne Financial Group, Inc. and took MidWestOne as the name of the company. In April 2011, then-chairman W. Richard Summerwill retired. In May 2015, the bank acquired Central Bancshares of Golden Valley, Minnesota for $134 million in cash and stock. In 2017, the bank opened its first branch in Denver, Colorado. In November 2017, Katie A. Lorenson, the chief financial officer of the company, resigned. In June 2018, Barry S. Ray was hired as the Chief Financial Officer.