Merger USA 03-04-2018 First Financial Bancorp. and MainSource Financial Group, Inc. complete merger First Financial Bancorp. (First Financial) announced that it has completed its previously-announced merger with MainSource Financial Group, Inc. (MainSource)… First Financial Bancorp. (First Financial) announced that it has completed its… Sign in or Upgrade to Continue Reading This news article is over 10 days old. Subscribe today to access all articles with an annual subscription. Become a member Learn more Already a subscriber? Log in here #commercial finance