Core Insights - Factor strategies that adjust the weighting of stocks in the S&P 500 have outperformed traditional market capitalization-weighted index funds in 2026 [1] Group 1: Performance of Alternative Strategies - Several index funds utilizing alternative strategies to track subsets of the S&P 500 or modify the index's weighting have shown strong performance so far in 2026 [1] - The traditional S&P 500 index is weighted by market capitalization, which has historically benefited large companies [1] Group 2: Concentration of the Index - The S&P 500 is currently 39.1% concentrated in its largest 10 companies by market capitalization, a decrease from 41.3% in October, which was the highest concentration level since at least 1972 [1]