The S&P 500 keeps climbing on days when stocks broadly struggle. Here's what's going on.

The article argues that concentrated investor focus on AI is amplifying moves in a small subset of mega-cap Big Tech stocks, which can swing a single trading session for the S&P 500. While it highlights potential volatility tied to these names, it provides no specific earnings, policy, or economic figures. Overall, it frames the dynamic as a sentiment/positioning factor rather than a clear fundamental catalyst.