SHANGHAI - Stocks on the Chinese mainland jumped the most in seven weeks on Tuesday. The advance came after a report on manufacturing eased investor concerns that the economic slowdown is deepening and as speculation intensified that the United States will announce a plan to boost growth.

A preliminary report from HSBC Holdings Plc and Markit Economics showed the purchasing managers' index (PMI) rose to 49.8 in August from the previous month.

"The August PMI is much better than market expectations that had been overly pessimistic," said Wu Kan, a fund manager at Dazhong Insurance Co, which oversees $285 million. "The market had priced in a possible negative impact."

The benchmark Shanghai Composite Index, rose 1.5 percent to 2554.02 at the close, the biggest increase since July 4. The gauge had lost 4.2 percent during a five-day slump. The CSI 300 Index gained 1.56 percent to 2821.

The Shanghai index has declined 9 percent this year as the central bank raised interest rates five times and ordered lenders to set aside more cash as deposit reserves 12 times since the start of 2010 to contain inflation that quickened to the fastest pace in three years last month. The measure is valued at 11.8 times estimated earnings, compared with a four-year low of 11.57 set on Monday, according to data compiled by Bloomberg.

Jiangxi Copper Co Ltd added 2.2 percent to 31.89 yuan ($4.98). Tongling Nonferrous Metals Group Co gained 2.6 percent to 23.51 yuan. Three-month copper on the London Metal Exchange climbed as much as 1 percent to $8,806.75 a ton. PetroChina Co Ltd, China's largest oil producer, climbed 1.2 percent to 9.89 yuan. China Petroleum & Chemical Corp advanced 2.4 percent to 7.15 yuan, the most since June 14.

The August PMI was 49.8 after a final reading of 49.3 for July, HSBC Holdings and Markit Economics said in a statement on Tuesday. A number below 50 indicates a contraction.

The figure was better than "rumored" and could provide relief to the market, according to Bank of America Merrill Lynch. The official PMI index for August to be released on Sept 1 by the National Bureau of Statistics could be higher than 50, Ting Lu, a Hong Kong-based economist at Merrill Lynch, wrote in a note on Tuesday.

The property developer China Vanke Co Ltd gained 1.7 percent to 8.22 yuan. China Minsheng Banking Corp rose 3.2 percent to 5.77 yuan, its highest close since July 15.

The chairman of the US Federal Reserve Board, Ben Bernanke, is scheduled to speak on Friday at a meeting of central bankers at Jackson Hole, Wyoming. The Standard & Poor's 500 Index rose 28 percent between Aug 26, 2010, and Feb 18 after Bernanke foreshadowed a $600-billion bond-purchase program a year ago in Jackson Hole.

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