US copper futures slumped almost 7 percent early on Friday, hitting limit-down after a flight of speculators from commodities for the second time in a week.
Copper for July fell 24.20 cents to $3.4690 a lb. on the New York Mercantile Exchange's COMEX division, swinging from a low $3.43 to a session high of $3.7180.
Spot May copper was down 22.65 cents at $3.6430, after bouncing off a morning low of $3.62. Still, it was well below last week's all-time COMEX record at $4.16, based on the spot continuation chart.
The maximum move allowed in a session is 20 cents and the market hit limit down within the first hour of trade.