NEW YORK, July 31 (Reuters) - General Motors Corp's GM.N benchmark long bonds hit a record low below 50 cents on the dollar on Thursday after finance company GMAC reported a $2.48 billion second-quarter loss.

GM's 8.375 percent bonds due in 2033 traded as low as 49.5 cents on the dollar, a record low in the institutional market, before bouncing to 50.9 cents, according to MarketAxess. They had closed on Wednesday at 51.5 cents on the dollar. (Reporting by Dena Aubin; Editing by Tom Hals) (dena.aubin@thomsonreuters.com; +1-646-223-6325; Reuters Messaging: dena.aubin.reuters.com@reuters.net))