AI stocks experienced a remarkable year: 3 of the S&P 500's top 4 performers in 2025 were data storage companies, benefiting from massive AI-driven spending. Sandisk, $SNDK, topped the list with a +559% return, followed by Western Digital, $WDC, and Seagate, $STX, at +284% and +225%, respectively. Meanwhile, Palantir, $PLTR, was the 9th best-performing stock in the index, posting a +135% return last year. This marked the 3rd-consecutive year of triple-digit gains for the stock. AI-related stocks dominated equity performance in 2025.