NEW YORK (Reuters) - American International Group Inc said on Wednesday it is preparing to launch a new business through Lloyd's of London Ltd that will serve U.S. high net worth clients.The business, which will operate as part of the Lloyd's of London global insurance marketplace, will support AIG's Private Client Group and provide additional new coverages to those clients, AIG said.AIG expects the business, dubbed "Syndicate 2019," to generate up to $1 billion in gross premiums to the Lloyd's..