First Solar (NASDAQ:FSLR) +3.5% in Thursday's trading but most solar shares trade lower after President Trump unveiled sweeping tariffs on imports to the U.S., including heavy levies on countries that are major manufacturers of solar products.

Tariffs on southeast Asia countries, as well as further action against Chinese products, could have the most obvious impact on the U.S. solar industry, with Vietnam slapped with a 46% tariff, Thailand suffers a 36% hit, Malaysia gets 24% and Cambodia is hit with a 49% tariff, as well as a further 34% levy on Chinese goods.

First Solar (NASDAQ:FSLR) rises as the only U.S.-headquartered company among the world's largest solar manufacturers, but other leading solar and alternative energy stocks are posting big losses, including Enphase Energy (ENPH) -7.9%, Solaredge Technologies (SEDG) -8.8%, Sunrun (RUN) -10.7%, Array Technologies (ARRY) -10%, Canadian Solar (CSIQ) -5.2%, Shoals Technologies (SHLS) -7%, Sunnova Energy (NOVA) -5.5%, JinkoSolar (JKS) -4.9%, Daqo New Energy (DQ) -9.9%, Bloom Energy (BE) -8.2%, Plug Power (PLUG) -6.4%.

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The current anti-dumping and countervailing duty tariffs which have raised the price of solar cells entering the country from the southeast Asian countries already have reduced the volume of imports compared with 2024, according to the U.S. Department of Commerce.

Southeast Asian countries and South Korea still account for the overwhelming majority of solar cells entering the U.S. to supply its growing module manufacturing industry, which may now become more expensive, PV-Tech.org reports.

While the U.S. has established ~50 GW of PV module manufacturing capacity, according to the Solar Energy Industries Association, the components needed to supply domestic factories are still mostly imported from Southeast Asia, with cell production lagging significantly behind module manufacturing capacity.