EXHIBIT (21)--SUBSIDIARIES OF THE REGISTRANT Name State of Incorporation Mainsource Bank Indiana Regional Bank Indiana Kentucky United Bancorp, Inc. Kentucky IUB Illinois Holdings, Inc. Indiana MainSource Bank of Illinois Illinois IUB Reinsurance Co., Ltd. Turks and Caicos MainSource Insurance, Inc. Indiana MSB Investments of Nevada, Inc. Nevada RB Investments, Inc. Nevada MainSource Statutory Trust I Connecticut MainSource Statutory Trust II Connecticut MainSource Statutory Trust III Delaware RB Holdings, Inc. Nevada MSB Holdings of Nevada, Inc. Nevada MSB of Nevada, LLC Nevada MSB Realty, Inc. Maryland RB of Nevada, LLC Nevada MainSource Title, LLC Indiana First Community Real Estate Management, Inc. Indiana Peoples Trust Company Indiana MainSource Mortgage, LLC Indiana