LONDON--(BUSINESS WIRE)--OM Asset Management plc (NYSE: OMAM) announced today the closing of an underwritten public offering of 15,295,000 of its ordinary shares, including 1,995,000 shares sold pursuant to the full exercise of the underwriters’ previously granted option to purchase additional shares. The shares were sold at a public offering price of $17.50 per share. The shares were sold by Old Mutual plc, through its wholly owned subsidiary, OM Group (UK) Limited. OMAM did not sell any share