The biggest names in American banking are urging the White House and Congress to stop lollygagging and cut a debt ceiling deal already. Chief executives Lloyd Blankfein of Goldman Sachs, Brian Moynihan of Bank of America, Jamie Dimon of JPMorgan (who's hounded Congress on this before), and others signed a letter requesting a deal by the end of the week. "A default on our nation's obligations, or a downgrade of America's credit rating, would be a tremendous blow to business and investor confidence--raising interest rates for everyone who borrows, undermining the value of the dollar, and roiling stock and bond markets--and, therefore, dramatically worsening our nation's already difficult economic circumstances," the letter read. According to MSNBC, "the letter joins the drumbeat from corporate America urging Washington to come to an agreement before the August 2 deadline to raise the nation's borrowing authority." Yesterday, executives at Wal-Mart and other big companies also entered the debt ceiling debate, bargaining for a drop in America's 35 percent corporate tax rate in exchange for giving up tax breaks. Others who signed today's letter included Citigroup's Vikram Pandit, Metlife's Steven Kandarian, and Morgan Stanley's James Gorman.