S&P stood for surprise and provocation last week, after Standard & Poor's revised the outlook on its triple-A rating of U.S. debt to negative from stable.

The credit-rating agency questioned whether President Barack Obama, a Democrat, and the Republican-controlled House of Representatives could strike a deal to rein in yawning federal budget deficits before the 2012 presidential election.

The bond and stock markets initially swooned on S&P's announcement, but soon recovered on optimism that the bombshell might force both sides to work together. The yield on the benchmark 10-year Treasury note ended the week at 3.41%, little changed from 3.40% the week before.