Omnicom Group Inc. has entered into a merger agreement with Interpublic Group of Companies Inc., where IPG will become a wholly owned subsidiary of Omnicom, with shareholders receiving 0.344 shares of Omnicom for each share of IPG they own, and the merger is expected to be tax-free. Additionally, amendments to executive agreements were made, extending expiration dates to December 31, 2027, and IPG's bylaws were amended to include an exclusive forum provision.