Dec 21 (Bloomberg) --  Copper rose the most in a week in New York amid speculation that the U.S. economy is recovering and after hedge funds increased bets the metal will gain.

The U.S. Commerce Department on Dec. 22 may revise its estimate for third-quarter growth to an annualized 2.8 percent, according to a Bloomberg News survey of economists, up from a previous estimate of 2.5 percent. Hedge funds have the biggest net-long position, or bets on higher New York prices, in five years, government data show.

"The market is just firm going into year-end,” said David Thurtell, an analyst at Citigroup Inc. in London. "Hedge funds want to keep them high in order to have good performance figures and they probably also anticipate good New Year inflows.”

Copper futures for delivery in March added 4.7 cents, or 1.1 percent, to close at $4.206 a pound at 1:01 p.m. on the Comex in New York. That’s the biggest one-day gain for a most- active contract since Dec. 13. The metal has surged 46 percent since July 1, partly on demand from emerging markets.

Speculative long positions, or bets copper prices will rise, outnumbered short positions by 30,268 contracts on the Comex division of the New York Mercantile Exchange in the week ended Dec. 14, the Washington-based Commodity Futures Trading Commission said on Dec. 17. That was the highest net-long since March 2005.

On the London Metal Exchange, copper for delivery in three months climbed $131, or 1.4 percent, to $9,201 a metric ton ($4.17 a pound).

Tin, aluminum, zinc and lead also gained in London. Nickel fell.