STEVENSON, Md.--(BUSINESS WIRE)--The securities litigation law firm of Brower Piven, A Professional Corporation, has commenced an investigation into possible breaches of fiduciary duty and other violations of state law by the Board of Directors of OM Group, Inc. (“OM Group” or the “Company”) (NYSE: OMG) relating to the proposed buyout of the Company by funds managed by affiliates of Apollo Global Management, LLC. Under the terms of the transaction, OM Group shareholders are anticipated to recei