Net bullish bets on copper rose to the highest level on record in CFTC data going back to 2006 for the week ended Tuesday. Bets on a higher copper price outnumbered those on a lower price by 91,191 contracts, exceeding the previous record set in December of 87,015. Copper prices have climbed on an improving outlook for demand, as well as potential supply disruptions amid contract negotiations at key copper mines. The threat of a worker strike has supported copper prices, and analysts expect global copper mine supply to decline in 2017. Prices closed up 0.6% at $2.6895 a pound on the Comex division of the New York Mercantile Exchange, and hit a new 52-week high on Wednesday.