Scott Rubner, Head of Equity and Derivatives Strategy at Citadel Securities, noted in his latest research report that retail investors net bought $9.1 billion in US equities through the firm's platform last week, marking the largest single-week net purchase in nearly 15 years. Funds were highly concentrated in AI-related stocks and ETFs, with semiconductor stocks seeing approximately $2.6 billion in net purchases and AI infrastructure-related stocks seeing approximately $2.4 billion in net purchases. Rubner emphasized that this round of buying primarily stemmed from "stronger directional conviction rather than an increase in overall trading volume," indicating that retail investors are actively and concentratedly betting on the AI sector.