SEOUL, June 20 (UPI) -- Michael Byungju Kim, who worked at Goldman Sachs and the Carlyle Group, founded MBK Partners in 2005. Over the next two decades, he built it into one of Asia's leading private equity funds through aggressive mergers and acquisitions. It now manages up to $30 billion in assets. However, Chairman Kim and MBK face challenges, because of its major investments in Home Plus, South Korea's No. 2 discount chain, and Lotte Card, the country's fifth-largest card issuer. This