US Retail Investors Buy AI Stocks Again, Log Biggest Weekly Net Purchases in 15 Weeks

US retail investors ramped up purchases of artificial intelligence-related stocks and exchange-traded funds, lifting weekly net buying to the highest level in 15 weeks.

Bloomberg reported on October 13 that Scott Rubner, Citadel Securities’ head of equity and equity derivatives strategy, wrote in a recent note that US retail investors were net buyers of $9.1 billion of stocks through the firm’s platform last week. Overall trading activity remained below average, but money was concentrated in AI-related names, driving net buying to its strongest level in the past 15 weeks.

Buying was especially pronounced in semiconductor stocks. Retail investors were net buyers of $2.6 billion of chip shares last week, marking the third-largest weekly net purchase in the past year. Demand for semiconductor investments continued despite concerns over the sustainability of AI industry growth, increasing the likelihood that October could become a record month for net retail buying of semiconductor stocks on Citadel Securities’ platform.

AI infrastructure-related names also drew about $2.4 billion in net inflows. Even as warnings persist that the AI industry is in a bubble, retail investors continue to bet on the growth prospects of related companies. Amid the buying, both the tech-heavy Nasdaq 100 and the S&P 500 reached fresh record highs last week.

Rubner had previously forecast that money would flow back into US equities in October after retail buying slowed sharply in September. With companies set to report earnings and resume share buybacks, October could provide investors with an opportunity to raise their equity allocations again.

Still, the latest increase in buying appears to reflect stronger investor conviction about the market’s direction rather than a surge in trading volume. Retail investors’ purchases last week were 2.7% higher than their sales, while a buy-sell directional gauge ranked in the top 10% of readings over the past year. By contrast, overall trading activity stood at the 42nd percentile of its one-year range. For Rubner, that suggests trading itself has not become more active and that investors are buying with greater confidence in a specific direction.