Copper prices lost ground Wednesday as global events such as Japan's crisis renewed concerns about demand in the next few months.
Copper for May delivery fell 7.25 cents to settle at $4.274 a pound. The price has fallen nearly 5 percent since March 1.
Investors question whether copper demand will soften with Japan's recovery from the earthquake and tsunami, Europe's ongoing financial problems and rising oil prices, CPM Group analyst Carlos Sanchez said.
Copper is used in manufacturing a variety of consumer products, from construction materials to electronics and some auto parts.
Thousands of factories in Japan were idled by tsunami damage and power disruptions after the devastating earthquake earlier this month. That has left shortages of auto parts and technology components.
Meanwhile, Portugal's borrowing rates continued to rise, which could weaken market confidence in the region's ability to resolve the crisis. Europe already has arranged multi-billion dollar bailouts for Greece and Ireland.
There also are concerns that oil prices above $100 a barrel may cause consumers and businesses to cut back consumption, Sanchez said.
June palladium rose $5.15 to settle at $758.10 an ounce and July platinum gained $30 to settle at $1,774.10 an ounce. May gold added $7.60 to settle at $1,423.80 an ounce and silver gained 52.4 cents to $37.511 an ounce.
In other trading, oil prices slipped after the Energy Department said U.S. crude supplies rose more than expected last week.
Crude supplies increased 2.9 million barrels to 355.7 million barrels, which is 0.4 percent above year-ago levels, the Energy Information Administration said.
Analysts expected an increase of 2.2 million barrels, according to Platts, the energy information arm of McGraw-Hill Cos.
Benchmark crude for May delivery lost 52 cents to settle at $104.27 per barrel on the New York Mercantile Exchange.
In April Nymex contracts, heating oil fell 0.39 cent to settle at $3.0534 per gallon and gasoline rose 1.37 cents to $3.0573 per gallon. Natural gas for May delivery added 9.2 cents to settle at $4.355 per 1,000 cubic feet.
Wheat, corn and soybeans were mixed ahead of a government forecast due Thursday on what crops farmers will plant this year.
In May contracts, wheat prices fell 10 cents to settle at $7.2725 a bushel, corn lost 8.5 cents to $6.6325 a bushel and soybeans rose 10.5 cents to $13.72 a bushel.