Copper ended afternoon kerb trading at the London Metal Exchange down 7.3 percent to $7,550 per tonne as investors, spooked by fear of rising inflation, pulled some money out of risky assets including commodities.
The metal's three-months futures contract, which under the steam of heavy buying from hedge funds and pension funds hit an all-time high of $8,800 last week, was down at $7,500 in electronic trading on Friday, its lowest for two weeks.
Fund sources said there was evidence that today's sell-off in commodities was part of an overall flight from risk in the financial markets as the spectre of higher inflation raised its head, but it did not mean buying was over for good.
"Some hot sectors have been sold off...a lot of hot money went into commodities, and the question is whether this is a considered retraction or a rout," said Sean Corrigan, chief investment strategist at Diapason Commodities Management, a commodities fund.
"At some point we will find the speculative selling is finished as people will go the other side (and buy long positions)...to say that this is the peak of the current wave of speculative buying is possible, but to say we've seen the peak of copper is more difficult," he said.
Copper has been extremely volatile recently, lurching by several hundred dollars within a day's trading, which has discouraged speculators taking either long or short positions.
"Some stops were triggered and a couple of funds trimmed their positions, but today was an order-driven market where nobody took any positions," a trader said.
"The sentiment is that it should stay firm until June and then be softer."
Copper's relative strength index (RSI) lost 19 points to 41 on Friday, and by comparison it was 91 on May 11, the same day it hit $8,800.
An RSI of 70-80 normally indicates that a market is overbought, and 20-30 that it is oversold.
Base metals, with copper foremost among them, were seen as the first movers that dragged the rest of the commodities complex with them.
Aluminium ended the kerb at $2,720, down $150, and zinc at $3,230, down $190.
Nickel was $950 lower at $20,500, lead down $60 at $1,150 and tin down $700 at $8,100.