Omnicom Group Inc. has entered into a merger agreement with The Interpublic Group of Companies, where IPG will become a wholly owned subsidiary of Omnicom, with an exchange ratio of 0.344 shares of Omnicom for each share of IPG. The merger is subject to various approvals and conditions, including stockholder votes and regulatory clearances, and is expected to be tax-free for U.S. federal income tax purposes.