Jiangxi Copper, China's largest copper smelter, warns copper faces more downside price pressure, as it posted a 52 per cent year-on-year fall in interim profit due to lower prices of the metal. "With a new round of release of copper mining capacity globally, and China's economic restructuring and slowdown, the copper market faces a change in demand and supply relationship," the firm said in a statement to the Shanghai stock exchange. Amid expectation that the United States will cut or end its bond-buying programme and continued economic weakness in Europe and Japan, copper price would be "further pressured", it added. Net profit for the year's first six months was 1.28 billion yuan (HK$1.61 billion) under international accounting standards, compared with 2.67 billion yuan in the year-earlier period. The profit amounts to a third of the 3.84 billion yuan full-year net profit forecast based on the average estimate of 19 analysts polled by Bloomberg. Gross profit margin fell to 4 per cent from 6.3 per cent. Apart from a squeeze on profit margin, lower copper prices also saw the company book a 572.8 million yuan inventory valuation loss in the first half, up from 86.4 million yuan in the year-earlier period. It also booked a loss of 109.4 million yuan "fair value changes" on derivatives contracts, which are related to its metal price hedging activities. This compares with a gain of 175.7 million yuan in last year's first half. Investment gains in the first six months of this year also shrank, to 47.6 million yuan from 290.2 million yuan, largely caused by a 142.9 million yuan loss on gold futures contracts. Revenue rose 31 per cent year on year to 88 billion yuan, as higher sales volume more than offset a fall in average selling price. It did not provide details on its sales by volume and price. Refined copper output grew 11.7 per cent to 558,800 tonnes, while that of copper wires surged 75 per cent to 353,000 tonnes. The average London Metal Exchange spot-market copper price in the year's first six months slid 6.9 per cent to US$7,546 a tonne. The benchmark has fallen 11 per cent this year, fetching around US$7,287 a tonne. Jiangxi Copper posted in late April a first-quarter net profit of 970.6 million yuan, based on mainland accounting standards, down 32.3 per cent year on year.