A federal appeals court has rebuffed the bid by American International Group’s mortgage insurance unit to overturn a lower court’s order to pay more than $45 million to SunTrust Banks for insured losses related to mortgage defaults. The Fourth Circuit Court of Appeals last week upheld a Virginia federal judge’s ruling that AIG’s United Guaranty breached an insurance agreement by refusing to pay claims on 1,305 defaulted “combo” loans – which is a first-lien loan with a smaller, second-lien “piggyback” loan. At issue were mortgage defaults that SunTrust claimed should have been covered under a ...