Trustmark Corporation and BancTrust Financial Group, Inc. Announce Definitive Merger Agreement

Trustmark Corporation

and BancTrust Financial Group, Inc.

announced today the signing of a definitive agreement pursuant to which BancTrust will merge into Trustmark. BancTrust has 49 offices throughout Alabama and the Florida Panhandle with $1.3 billion in loans and $1.8 billion in deposits as of March 31, 2012. Under the terms of the definitive agreement, which has been approved unanimously by the Boards of Directors of both companies, holders of BancTrust common stock will receive 0.125 shares of Trustmark common stock for each share of BancTrust common stock in a tax-free exchange. Trustmark will issue approximately 2,245,923 shares of its common stock for all issued and outstanding shares of BancTrust common stock. Based upon a price of $24.66 per share of Trustmark common stock, the transaction is valued at approximately $55.4 million, or $3.08 per share of BancTrust common stock. Trustmark intends to repurchase the $50.0 million of BancTrust preferred stock and associated warrant issued to the U. S. Department of Treasury under the Capital Purchase Program. Daniel A. Grafton, Chairman of Trustmark, said, “BancTrust is a respected financial institution with long-standing customer relationships. This transaction provides an excellent opportunity for Trustmark to enhance its franchise by expanding into attractive Alabama markets, including Mobile and Montgomery, as well as increase scale in our existing Florida Panhandle markets.”