Copper advanced for a sixth straight session to an all-time high close to $12,300 on Wednesday as robust U.S. economic growth boosted demand prospects and a weaker dollar supported prices. Benchmark three-month copper on the London Metal Exchange was up 1.1% to $12,195 a metric ton as of 1010 GMT, having earlier hit a record $12,282. The metal has gained 2.6% this week, is up 9% in December and on track for a 39% leap in 2025 as supply constraints lead to bullish copper bets. On the Shanghai Futures Exchange, copper also hit an all-time peak of 96,750 yuan ($13,793) a ton on Wednesday. “It wouldn’t surprise me if the Chinese are buying physical copper in the market - bringing in as much as they can get while no one is looking,” SP Angel analyst John Meyer said. The Yangshan premium, an indicator of Chinese appetite for copper imports, has shot up to $55 a ton, the highest since September 24. The U.S. economy grew at its fastest pace in two years in the third quarter, while the dollar was headed for its worst annual performance in more than two decades as investors bet on further rate cuts next year. A weaker greenback makes metals more affordable for holders of other currencies. Large amounts of copper have flowed to the United States in recent months, including more than 50,000 tons from China in November, as the prospect of a U.S. tariff on the metal lingers. Among other LME metals, aluminium was up 0.6% at $2,956 a ton, after hitting its highest since May 2022. Zinc nudged up 0.2% to $3,098, lead added 0.6% to $1,994.50, while tin climbed 1% to $43,005. Nickel rose for a sixth day on expectations Indonesia will cut ore output next year, and was up 0.6% at $15,835. The LME ring, the open-outcry trading floor, will close early, at 1440 GMT, on Wednesday, before the exchange shuts on Thursday and Friday for the Christmas holiday.