The Louisville Arena Authority is postponing the sale of $360 million in construction bonds until next week because of concerns about the financial health of the company backing the debt.Assured Guaranty is the company that will insure the bonds. Moody's Investors Service has signaled that it may downgrade its opinion of the company. A number of bond insurers have been downgraded because of the troubled credit markets.Arena Authority chair Jim Host says he expects the bond deal will now close next Wednesday, July 30. He didn't say how construction plans for the new arena might be affected if Moody's downgrades the insurer.