First Solar Inc. ( FSLR ) led a surge in U.S.-based solar companies Tuesday after the Trump administration finalized steep new tariffs stemming from a trade investigation initiated during the Biden presidency. The Commerce Department finalized duties that could reach as high as 3,521%, targeting manufacturers in Cambodia, Vietnam, Thailand, and Malaysia for dumping subsidized products in the American market. First Solar, which helped spearhead the complaint, saw its shares climb over 10% in early trading. The move represents a significant victory for domestic manufacturers, long embattled by low-cost competition supported by foreign subsidies. Other U.S.-based solar names, including Hanwha Q Cells and smaller players like T1 Energy, also posted notable gains. “This is a decisive victory for American manufacturing,” said Tim Brightbill, counsel for the coalition of U.S. producers that initiated the probe. The ruling underscores years-long allegations that Chinese solar firms used Southe...