Silver prices drifted lower by 0.43% to Rs.40,638/kg in futures market today, tracking a weak trend overseas. At the Multi Commodity Exchange, silver for delivery in December fell by Rs.176 or 0.43% to Rs.40,638/kg in business turnover of 1,259 lots. The white metal for delivery in March next year was trading lower by Rs.144 or 0.35% to Rs.41,239/kg in 53 lots.