ASML Holding and shares of other companies in the semiconductor sector were dropping Monday. The prospect of a trade war between the European Union and the U.S. is hurting chip stocks.

Dutch company ASML was down 3.3% in trading in the Netherlands. Germany's automotive chip company Infineon Technologies was falling 3% and STMicroelectronics -- which supplies Tesla and other auto makers -- was dropping 4.8%.

President Donald Trump on Saturday threatened to hit eight NATO member states, including the Netherlands, Germany and France, with 10% tariffs from Feb. 1 unless they agree to the U.S.'s acquisition of the Danish territory of Greenland, rising to 25% from June 1.

ASML is arguably Europe's single most important exporter to the U.S., as it holds a near-monopoly on the lithography machines which are crucial for manufacturing the most advanced semiconductors. The U.S. accounted for 16% of ASML's revenue in 2024, according to FactSet, although the large price tag for the company's individual machines mean numbers can vary widely by year.

An increased tariff on ASML's products would potentially be painful for American chip companies such as Intel and memory-chip maker Micron Technology, as well as foreign companies investing in U.S.-based facilities such as Taiwan Semiconductor Manufacturing.