Copper sustained its largest one-day decline in nearly three weeks on Thursday as losses piled up late alongside an accelerated downturn in equities and on a bearish technical break that could keep prices under pressure in the near term. In New York, the key December COMEX contract fell 10.20 cents or nearly 3 percent to settle at $3.3825 per lb, near the bottom end of its $3.3625 to $3.4920 range.
Technical selling kicked in after the price broke to the downside of an ascending triangle formation, a move that could kick-start another leg lower, analysts said. As the selling accelerated, so too did trading volume. More than 65,000 lots traded late in New York, up nearly 12 percent from the 30-day norm, according to preliminary Thomson Reuters data.