MC S&P 500 Heatmap, 5/1/26: Narrow leadership, weak breadth

The heatmap pointed to a market being held up by selective leadership rather than broad participation. The tape leaned narrow, with strength concentrated in pockets while large parts of the map lagged, giving the index a more stable appearance than the underlying breadth justified.

This was a fragile grind supported by a few leaders, with rotation failing to fully broaden out. Mega-cap influence remained important, but not cohesive enough to signal a unified growth push, leaving the overall tone closer to cautious than expansionary.