In June 2015, Taiwan's Nan Shan Life Insurance acquired a stake in AIG's subsidiary in Taiwan for a fee of $158 million. Later that year, activist investor Carl Icahn called for a breakup of AIG, describing the company as "too big to succeed". AIG announced plans for an initial public offering of 19.9 percent of United Guaranty Corp., a Greensboro, North Carolina-based provider of mortgage insurance for lenders in January 2016. Later that year, Icahn won a seat on the board of directors and continued to pressure the company to split up its major divisions. AIG also began a joint venture with Hamilton Insurance Group and Two Sigma Investments to serve the insurance needs of small- to medium-sized enterprises. Industry veteran Brian Duperreault became the chairman of the new entity, and Richard Friesenhahn, the executive vice president of U.S. casualty lines at AIG, became CEO. In August 2016, AIG sold off United Guaranty, its mortgage-guarantee unit, to Arch Capital Group, a Bermuda-based insurer, for $3.4 billion.