On May 21, base metals prices on the London Metal Exchange traded mostly lower, with weakness in copper, nickel and zinc outweighing gains in lead and aluminium . Lead recorded the highest increase, rising 1.26% day-on-day to $2,005 per tonne, while aluminium edged higher by 0.40% to $3,637 per tonne . Meanwhile, nickel declined 1.07% to $18,727 per tonne, followed by copper and zinc, which fell 1.03% and 0.93% to $13,516 per tonne and $3,523 per tonne, respectively . LME inventory trends remained mixed: lead stocks recorded a sharp increase of 8.43%, while zinc, aluminium and copper stocks declined, indicating selective tightness across exchange-monitored warehouses . Market participants remained cautious over ongoing uncertainty surrounding US-Iran peace negotiations and potential supply disruptions in the Middle East .