Exclusive: S&P to deeply cut U.S. ratings if debt payment missed

(Reuters) - The United States would immediately have its top-notch credit rating slashed to "selective default" if it misses a debt payment on August 4, Standard & Poor's managing director John Chambers told Reuters.
Chambers, who is also the chairman of S&P's sovereign ratings committee, told Reuters on Tuesday that U.S. Treasury bills maturing on August 4 would be rated 'D' if the government fails to honor them. Unaffected Treasuries would be downgraded as well, but not as sharply, he said.
"If the U.S. government misses a payment, it goes to D," Chambers said. "That would happen right after August 4, when the bills mature, because they don't have a grace period."
Fears of a technical default have been rising after budget negotiations between Democrats and Republicans fell apart in Washington earlier this week. Even a brief default by the United States would immediately increase the country's borrowing costs, weighing on the fragile economic recovery and eroding the dollar's status as a reserve currency.
On August 4, the Treasury Department is due to pay off $30 billion in maturing short-term debt.

http://www.reuters.com/article/2011/06/29/us-usa-debt-sandp-idUSTRE75S5GV20110629