Even though it dropped by half, it's still super impressive. SNDK is the best-performing stock in the S&P 500 for 2025, way ahead of the pack. SNDK is also the best-performing stock in the S&P 500 for 2026, still way ahead. SNDK has fallen 50% from its all-time high a few months ago, but it's still up over 400% year-to-date.