U.S. stocks advanced, driving the Standard & Poor’s 500 Index toward the biggest increase in almost a month, after China signaled it would support the economy and German and French officials met before a summit.

Stocks rebounded from a four-month low as Chinese Premier Wen Jiabao pledged to focus more on bolstering growth. Germany and France agree that they will do “everything necessary” to ensure Greece remains in Europe’s single currency, Finance Minister Wolfgang Schaeuble said today in Berlin after a meeting with French Finance Minister Pierre Moscovici. European Union leaders are preparing for a summit in Brussels on May 23.

Greece may have to exit the 17-nation euro and the monetary union should plan for it to ensure

Cooper Industries jumped 26 percent, the most in the S&P 500, to $70.58. Each Cooper share will be exchanged for $39.15 in cash and 0.77479 Eaton share. That offer is valued at $72 a share based on Eaton’s May 18 closing price, 29 percent more than Cooper’s price that day, according to the statement.

Financial shares in the S&P 500 rallied, following last week’s 7 percent tumble, even as JPMorgan Chase & Co. (JPM) retreated. The lender, which lost 3.7 percent earlier today, fell 1.7 percent to $32.92. JPMorgan suspended its daily stock repurchase program because the bank needs the money to meet international capital rules, not because of trading losses, Chief Executive Officer Jamie Dimon said.

Facebook tumbled 11 percent to $34.05. It rose 0.6 percent in its first day of trading on May 18. The offering valued Facebook at 107 times trailing 12-month earnings, more than every S&P 500 member except Amazon.com Inc. and Equity Residential. Facebook is trying to attract more marketers to boost sales as competition increases. General Motors Co. last week announced plans to cut Facebook advertising.

Lowe’s Cos. slumped 9.7 percent, the most in the S&P 500, to $25.73. The second-largest U.S. home-improvement retailer reduced its forecast for full-year earnings to a range of $1.73 to $1.83 from $1.75 to $1.85 because of a smaller increase in profit margins than it had previously expected.