The new highs vs. new lows count is a direct, intuitive breadth read: how many stocks are making new highs versus new lows. It cuts through the index-level noise to tell you whether the average stock is strong or weak — a useful confirmation tell for SPY trend days.
How to read it
When SPY is rising, you want to see new highs expanding and new lows minimal — that confirms broad strength and a healthy trend. If SPY is climbing but new highs are shrinking (or new lows are creeping up), that's a breadth divergence warning the rally is narrowing. On a selloff, expanding new lows confirm real weakness; contracting new lows into a decline can hint at exhaustion (fewer stocks making fresh lows even as the index falls).
Why it works
New highs/lows measure participation at the extremes — the stocks actually leading or breaking down. A trend supported by expanding new highs has real, broad power behind it; one where the new-high count is dwindling is running on a shrinking group of leaders and is vulnerable. The tell is especially valuable at potential turning points, where the internals often shift before the index does.
The index can lie; the new-highs count can't. It counts the actual leaders — and when their number shrinks under a rising market, the trend is living on borrowed time.
Using it as a scalper
Treat new highs/lows as a trend-quality gauge, not a precise timing tool. On a trend day, confirming breadth (expanding highs with an up-move) supports trading with the trend and trusting continuation; diverging breadth argues for caution and skepticism about follow-through. It's context for your live map read, working alongside the equal-weight comparison and the advance-decline line to reveal whether the market's move is broad and durable or narrow and fragile.