Aug. 23 (Bloomberg) –Copper gained after data showed Chinese imports rebounded to the highest level since January and on speculation that the U.S. will announce additional measures to shore up the recovery. Zinc and lead also advanced.

Three-month copper on the London Metal Exchange climbed as much as 1.5 percent to $8,850 a metric ton and traded at $8,839 as of 3:03 p.m. Shanghai time. The contract declined 1.2 percent yesterday, after losing 10 percent in the past three weeks. The November-delivery contract on the Shanghai Futures Exchange closed 1.1 percent higher at 66,650 yuan ($10,418) a ton.

Both scrap and refined copper imports in July rose from the previous month and were above the year-to-date average, Chinese customs data showed yesterday. Inbound shipments of refined metal gained for a second month to 194,280 tons and scrap imports rose to 432,317 tons, the highest level since December.

"This, together with strong growth in domestic refined output paints a robust picture of metal demand in China," Gayle Berry, an analyst at Barclays Capital, said in a research report yesterday. "This buying is all the more impressive since it comes at a seasonally slower period of end-user activity."

China's refined copper production climbed 18 percent from a year earlier to a record of 478,000 tons in July, said the National Bureau of Statistics on Aug. 9.

Metals were also boosted after the country's August HSBC flash Purchasing Managers' Index stood at 49.8 after a final reading of 49.3 for July, HSBC Holdings Plc and Markit Economics said in a statement today. The final August reading is due Sept. 1. A reading below 50 indicates a contraction.

Better Than Rumored
The preliminary manufacturing gauge of 49.8 was better than the "rumored" number of 45, and could provide some relief to the market, according to Ting Lu, a Hong Kong-based economist at Bank of America Merrill Lynch. The official PMI index for August to be released by the National Bureau of Statistics may be above the 50-threshold for expansion, he wrote in a note.

The U.S. Federal Reserve is holding its annual symposium in Jackson Hole, Wyoming, this weekend. This time last year Chairman Ben S. Bernanke hinted that the central bank might embark on a second round of asset purchases, kicking off a 28 percent rally in the S&P 500 that ended in a three-year high on April 29.

"The chance for additional stimulus is quite big," Wang Jingjing, an analyst at Founder Futures Co., said by phone from Changsha city in Hunan province. "If it comes out as expected, at least in the short-run, it will help to boost market confidence."

Aluminum in London rose 0.3 percent to $2,344.25 a ton, zinc gained 1.4 percent to $2,183 a ton, and lead climbed 1.2 percent to $2,287 a ton. Nickel climbed 1.1 percent to $21,075 a ton, and tin advanced 2 percent to $23,300 a ton.