Whenever I come across the market breadth argument, it reminds me of the old-school traders around 2015 who began realizing that you couldn’t simply use bond-equity correlations from the 1970s to identify current market regimes. Over time, market structure changes, relationships evolve, and historically reliable signals can become far less useful. I think we are seeing something similar with market breadth today. The massive growth in single-stock options has introduced another layer of reflexivity and price discovery into equity markets, driven by both end-user positioning and the dealers hedging that risk. Naturally, that means the relationship between individual stocks and the broader index today is meaningfully different from what it was even six years ago. The increasing crowding of dispersion trading has amplified this dynamic even further. One consequence is that, over the last few years, traditional long-only equity investors have often increased exposure as market breadth improves. Yet, contrary to what historically worked, those periods have frequently turned out to be precisely the wrong time to add exposure. The broader point is simple: market breadth is not a static signal. Its behavior has changed materially as the underlying microstructure of equity and options markets has evolved. If you continue relying on older breadth metrics without accounting for those structural changes, you risk applying yesterday’s framework to today’s market.