Shares of Advanced Micro Devices (AMD) fell approximately 2.5% in premarket trading on September 28, 2026. The decline followed OpenAI’s announcement that it had paused training and testing some of its most advanced AI models to improve safety measures. The news raised investor concerns about a potential slowdown in demand for high-performance AI chips from major developers.
The broader semiconductor sector also faced pressure from rising oil prices amid renewed U.S.-Iran tensions. Those tensions revived concerns about inflation and the potential impact on interest rates.
Despite the sell-off, some retail investors on platforms such as Stocktwits remained bullish on AMD’s long-term prospects. The news came a week after AMD’s market capitalization surpassed $1 trillion, driven by a strong AI-led rally.