European AI-related semiconductor companies saw significant share price drops on Monday (September 14), with ASML falling by approximately 5.2%, French semiconductor materials company Soitec by about 12.6%, ASM International by 8.7%, and Infineon by 7.6%. The sell-off was primarily driven by investors questioning the pace of future AI infrastructure spending, as well as calls from some prominent figures in the AI field to slow down the development of frontier AI models.