Company size can shape investment returns as much as sector does. Through October 2, 2026, the S&P SmallCap 600 gained 16.30%, ahead of the S&P 500 at 13.79% and the S&P MidCap 400 at 12.08%. Small caps also beat their larger peers in eight of eleven sectors. Patrick Simpkins breaks down what the numbers show and what to watch next.