(ShareCast News) - Old Mutual will float two thirds of its asset management business on the London Stock Exchange for what is expected to be around $1.1bn and then continue to reduce it holdings, using the proceeds for "general corporate purposes".Some 13m shares will be sold in the public offering by Old Mutual, brokered by Bank of America Merrill Lynch, Morgan Stanley, Citi, Credit Suisse and Evercore. The underwriters have a 30-day option to buy an additional 1.95m shares.The bank said it will continue to reduce its holdings in the asset management business in a way that balances "value, cost, time and risk".The public offering is subject to a registration statement from the US Securities and Exchange Commission and a preliminary prospectus supplement has been filed with the SEC.