Alcoa shares tumble after cyclone cuts into alumina output

Alcoa Corp. cut its production forecast for alumina after operational problems at an Australian refinery weighed on output, overshadowing a quarter in which higher aluminum prices helped lift the metal producer’s revenue. 

The Pittsburgh-based company lowered its 2026 guidance for alumina production — the refined material needed to make aluminum metal — to between 9.5 million and 9.6 million metric tons, down from a previous outlook of 9.7 million to 9.9 million tons, according to a statement Thursday. It also reduced its forecast for alumina shipments, while leaving its outlook for aluminum production and shipments unchanged.

Alcoa shares fell more than 7% in after-market trading before paring losses. 

The weaker outlook reflects lower production at Alcoa’s Pinjarra refinery in Western Australia after instability that began in late March was worsened by gas supply disruptions linked to Cyclone Narelle, the company said. The refinery is one of Alcoa’s largest sources of alumina, a critical intermediate product between bauxite mining and aluminum smelting. 

The guidance overshadowed a stronger quarter for Alcoa’s aluminum business, which has benefitted from a rally in metal prices and the restart of idled smelters. The firm’s aluminum segment increased to $1.07 billion in adjusted Ebitda, exceeding analysts’ estimates. 

Aluminum prices have climbed about 20% over the past 12 months, buoyed by supply disruptions out of the Middle East and expectations that demand from power grids, data centers and the energy transition will outpace new production. The higher prices helped drive Alcoa’s quarterly revenue to a record of about $4 billion. 

The results come weeks after Alcoa agreed to acquire South32 Ltd.’s alumina, aluminum and bauxite business for as much as $5.6 billion, betting that demand for the lightweight metal will continue to grow.