COMEX copper trimmed its losses by the close but traders said the market may see more selling next week as it will still need to digest the unexpectedly large number of delivery notices issued and the array of mixed economic data released on Friday.
Friday was first notice day for the March contract and one broker pointed out that the more than 10,000 notices issued for 125,000 tonnes of copper "took everybody by surprise."
The raft of US data also pressured prices, but some of the more positive reports offered support, traders said.
"I think the move today was mostly technical, but it did put things in the back of people's mind. The GDP was better today," said one trader.
Most-active May copper closed down 0.80 cent at $1.3460 a lb., in a $1.3295 to $1.3555 range.
The high formed a double-top with Thursday's high. May copper reached a peak dating back eight years at $1.3600 a lb. on Wednesday.
Spot March fell 0.50 to $1.3430 a lb. The rest settled 0.30 to 0.70 lower.
COMEX estimated final copper volume at 17,000 lots, less than the 24,772 lots traded on Thursday. Open interest rose on Thursday by 1,136 contracts to 93,018.
The US economic data released on Friday were mixed in terms of implications for copper demand.
Copper was sold on the declining University of Michigan consumer sentiment index. For February, it came in at 94.4 versus January's 103.8.
Copper's downside was limited, however, by a better reading in business activity in the US Midwest. The Chicago area business barometer fell to 63.6 in February from 65.9, but indicated business in the region continued to expand for the 10th consecutive month.
With copper volatility increasing with the market at eight-year highs, many players are becoming wary of staying in the market.
In London, LME 3-months copper finished on Friday with modest gains at $2,938 a tonne, up $16.
The session range was $2,912 to $2,977, nearly forming a triple top at the 8-1/2 year peak of $2,980 per tonne.