ASML Holding NV's stock experienced a significant intraday decline of 8.44% on Tuesday, reflecting heightened investor anxiety over regulatory challenges and broader pressures within the semiconductor equipment sector.

The sharp drop followed allegations by U.S. Commerce Secretary Howard Lutnick that ASML may have allowed an advanced EUV lithography system to reach China in violation of existing export controls. ASML firmly denied these accusations, stating it has never exported any EUV system or EUV-specific components to China and emphasized the comprehensive tracking of each machine. The controversy comes as ASML reported a 56% quarter-over-quarter plunge in China mainland system sales in the first quarter, with the region's share of group system revenue dropping from 36% to 19%.

The sell-off occurred alongside broad weakness in semiconductor equipment stocks and a global rout of technology shares, as investors reassessed sky-high valuations in AI-related names. European tech stocks joined an accelerating global selloff, with ASML—Europe's most valuable company—losing substantial market value. The broader semiconductor equipment sector declined sharply, with peers like Applied Materials, Lam Research, and KLA-Tencor also posting notable losses, reflecting heightened concerns over potential further tightening of chip equipment export controls.