Base metals on the London Metal Exchange closed mostly lower on Tuesday, with the downward trend driven by a combination of tightening macroeconomic expectations and divergent fundamentals across individual commodities.

The three-month copper contract settled at $14,232.50 per metric ton, down $92.00 from the prior session's close, representing a decline of 0.64%. Meanwhile, three-month aluminum finished at $3,229.50 per ton, dropping $14.50, or 0.45%, from the previous trading day.

Three-month nickel posted a loss of $130.00 to close at $16,920.00 per ton, a decrease of 0.76%. In contrast, three-month lead bucked the broader trend, edging up $9.50 to settle at $1,905.50 per ton, a gain of 0.50%.

Three-month tin saw the steepest decline among the major metals, falling $685.00 to close at $55,100.00 per ton, down 1.23% from the previous close. Three-month zinc was virtually flat, inching up just $1.00 to finish at $3,885.50 per ton, an increase of 0.03%.

The broad-based weakness across most base metals reflects growing expectations of tighter monetary policy. Stronger-than-expected U.S. July PCE inflation data has pushed the probability of a Federal Reserve rate hike in September to 42%, while a firmer U.S. dollar index has placed systematic downward pressure on metal valuations.

Additionally, reports of a potential U.S.-Iran ceasefire agreement have reduced geopolitical risk premiums, further eroding supply-side support for the complex. Against this backdrop, the varying supply-demand fundamentals of each metal ultimately dictated the divergent price movements seen in Tuesday's session.