Glencore has reduced its stake in Century Aluminum from 43% to 33%, capitalizing on a sharp rise in Century’s share price following the U.S. decision to double aluminum import tariffs to 50% on June 4. The tariff move aimed to spur domestic investment and boost profits for U.S. aluminum smelters.

Glencore, Century’s largest shareholder and key supplier of alumina, sold nine million shares on November 10 for US$272.25 million and converted its Series A Convertible Preferred Stock into 4.95 million ordinary shares, according to a U.S. regulatory filing.

Century’s stock has risen 80% since June, supported by higher U.S. aluminum prices. Glencore now holds about 36 million shares and said it remains confident in Century’s management while monetizing part of its investment.

Century is the largest primary aluminum producer in the United States, with nearly 700,000 tons of annual capacity, while U.S. aluminum imports reached 3.94 million tons last year.