* CME will adjust orders
By Josephine Mason
NEW YORK, Dec 24 (Reuters) - New York copper futures jumped over 2 percent on Tuesday after an erroneous buy order sent prices to their highest levels since April, triggering buy stops and roiling quiet pre-holiday trade, traders and sources said.
The big buy order placed in the most-active March futures contract shortly before midday in New York sent prices up over 11 cents to $3.4475/lb, its loftiest level since April, in a matter of minutes.
"There was an error trade," a spokesman for the CME exchange said.
The CME Group Inc will adjust any orders above $3.42 per lb placed after 11:49 a.m. EST (1549 GMT) back to that level, it said in a notice to members seen by Reuters.
"Anytime you have a light trade such as a holiday market, this is a possibility. Someone was probably filling in and put in a bad trade or a fat finger trade," Art Liming, futures specialist for Citigroup said.
The timing coming just an hour before the market closed for the Christmas holiday may have increased the impact on prices. Trading on COMEX will resume on Thursday.
Almost a third of March contract's turnover for the day went across traders' screens in a 15-minute period from 11:50 a.m. EST, according to Reuters data.
Before the order, prices were a touch higher underpinned by tightness in near-term supplies and increasing confidence about the U.S. economic recovery.
The market sustained the gains by the close, which was earlier than usual for the holidays, after prices hit pre-determined buy-stops above the market.
COMEX March copper prices settled at $3.374, up 2 percent, with over 3,100 lots traded on the day.
Orders for long-lasting U.S. manufactured goods surged in November and a gauge of planned business spending on capital goods recorded its largest increase in nearly a year.
Trading across commodity and financial markets was stable ahead of the Christmas holiday.