 CHARLOTTE, N.C.--BUSINESS WIRE--National investor fraud law firm, KlaymanToskes KT, has commenced an investigation of potential FINRA arbitration claims on behalf of former and current Oppenheimer Co., Inc. Oppenheimer NYSE: OPY customers who invested in the alleged Horizon Private Equity III Horizon Ponzi scheme. Investors are suing Oppenheimer for its role in enabling a massive Ponzi scheme devised by Marietta, Georgia resident and former Oppenheimer registered represent 