The S&P 500 rose 20.74% (+1,285 pts) over the past year on a mixed tape; AAPL, NVDA, MU did most of the lifting, with 36% of the gain between them.
NVIDIA CORP and OLD DOMINION FREIGHT LINE moved almost identically (+27.26% vs +30.03%), yet NVDA moved the S&P 500 11,985.3× as much. In a cap-weighted index, the bigger company's weight turns the same percentage move into far more points.