Tin traders probably added to wagers that the metal will gain as the number of outstanding contracts climbed to a three-month high at the same time as prices rose.
Open interest in London Metal Exchange tin futures climbed by 2,138 lots, or 8.9 percent, to 26,200 contracts in the week ended Feb. 1, the highest level since Oct. 13, according to LME figures. Each lot represents 5 metric tons of the metal used in packaging or to join metals together. The benchmark contract for three-month delivery advanced 7.6 percent in the period.
An increase in open interest as prices rise suggests new long positions, or bets on higher prices, according to Macquarie Group Ltd. Open interest in LME tin climbed 15 percent last month, the biggest increase since July 2009.
Following are changes to market open interest for both LME members and their clients for the six biggest industrial-metals futures traded on the exchange. The figures were compiled by the LME.
Change in Price Change Open Interest (%) Aluminum -12,088 0.6 Copper 7,188 0.7 Zinc 9,996 -2 Lead 11,236 -2.1 Nickel 4,262 0.2 Tin 2,138 7.6