Asian semiconductor stocks declined after OpenAI paused training, evaluation and inference with tool use for its most capable models while strengthening safety controls. SK Hynix fell 4.8%, Samsung Electronics dropped 4.6%, Kioxia Holdings declined 2.3%, and several Chinese chip and hardware companies also weakened. OpenAI said the pause followed a security incident involving an internal research model, leaving its largest planned frontier reinforcement-learning run on hold during a safeguards review. The selling spread to South Korea, China and Japan, although Hong Kong gained, while Taiwan’s market was closed for the September 28 Confucius’ Birthday/Teachers’ Day holiday. The developments renewed questions about the sustainability of AI-related investment in chips, servers and data centers. Earlier this month, Anthropic CEO Dario Amodei and OpenAI CEO Sam Altman supported a slower pace of AI development, prompting a sharp chip-stock selloff. The longer-term spending outlook remains mixed as Chinese technology companies expand domestic AI infrastructure and Alibaba plans a substantially larger AI model and a new in-house AI chip.