Dow Jones industrial average has its second-worst May in history

The Dow Jones industrial average ended the month down the most for any May since 1940 as a downgrade of Spain's debt rating and escalating tensions on the Korean Peninsula triggered a flight from riskier assets.

The Dow retreated 56.76 points, or 0.6 percent, to 10,136.63 last week, capping a 7.9 percent loss for the month.

The Standard & Poor's 500-stock index rose for the week, climbing 0.2 percent to 1,089.41, as increasing consumer confidence and China's commitment to maintain investments in Europe eased concern that a debt crisis is spreading.

"The correction in the U.S. stock market is a little bit overdone," said David Joy, chief market strategist at Columbia Management in Boston. "I've looked at this more or less as a buying opportunity."

Sprint Nextel Corp. led the S&P 500's weekly advance after Goldman Sachs boosted the stock's rating. Consumer companies and material producers increased more than 1 percent, while Apple surpassed Microsoft Corp. as the world's most valuable technology company.

The rise in confidence among U.S. consumers exceeded estimates, with the Conference Board's index rising to 63.3, the highest level in two years. The median economist forecast was 58.5 in a Bloomberg survey. Sales of previously owned American homes increased last month to the highest level in five months, according to the National Association of Realtors.

The Treasury will sell $27 billion in three-month and six-month bills Tuesday. They yielded 0.16 percent and 0.22 percent, respectively, in when-issued trading. The government also plans to auction $25 billion in one-year bills Wednesday. They yielded 0.36 percent in when-issued trading.

-- Bloomberg News