China has for the first time revealed the estimated size of its copper inventories, shedding light on one of the commodity market’s biggest mysteries. Chinese copper inventories stood at 1.9 million tons at the end of 2010, more than the U.S. consumes in a year, according to estimates by the state-backed China Non-Ferrous Metals Industry Association (CNIA). The estimate is significantly higher than the 1.0 million to 1.5 million tons range that foreign executives have assumed in the past. The estimates were announced at a meeting of the International Copper Study Group (ICSG) in Lisbon at the end of September, but they have not been made public. Movements in Chinese inventories are one of the most important price drivers for the global copper market. A buying spree in early 2009 by the country, which now accounts for about 40% of global copper demand, helped trigger a price rally from the lows of the financial crisis to new records this year above USD10,000 a ton. The CNIA estimated that Chinese copper stocks, not including those kept at Shanghai Futures Exchange (SHFE) warehouses, stood at 1.768 million tons at the end of 2010, up from 1.218 million in 2009 and 282,000 in 2008. SHFE inventories were 132,000 tons in 2010, putting China’s total stocks at 1.9 million tons. Analysts say China has an interest in inflating the size of its stockpiles to push prices down. They say China releases only sketchy information about its supply, demand and inventories, creating a statistical vacuum that is contributing to price volatility, the Financial Times reports.