American International Group has announced the completion of the sale of its private mortgage insurance subsidiary United Guaranty Corp. (UGC) to Arch Capital Group Ltd. (ACGL), creating what could be the largest private mortgage insurance company in the world. On paper, the combined entity would account for 26.9 percent of the market, based on traditional flow business during the first nine months of last year. But lenders are expected to re-calibrate how they distribute their MI business and not all current UGC business will go to the merged unit. In fact, UGC saw...