S&P 500 up 12%, but typical stock up under 5%

The S&P 500, the index tracking 500 large U.S. companies, was up about 12% in 2026 as of Oct. 16, Reuters reported, driven largely by AI-related tech stocks. The median stock, half above and half below, was up under 5% as of Oct. 13, Reuters reported. I read that as narrow leadership propping up your index fund.