Market Structure · Breadth-of-Breadth
How broad is the bull? We read it two ways. First the absolute tape — of the ~500 S&P 500 names, how many are above their moving averages, making new highs vs lows, positive on the year. Then a relative-ratio diffusion index across 17 structural proxies for the rotation underneath. Together they catch a narrow bull while the index still looks fine.
Updated daily · data as of 2026-09-15 · 17 ratios live
Related Beta Instability — the up/down-beta read on the same pairs →
The relative ratios further down read rotation; this reads the tape directly — of the ~500 S&P 500 names, how many actually participate. A bull can be narrow even with the index near highs.
MA chips = price above its 20/50/200-day average. Green-200 but red-20 = a leader rolling over; green across = a laggard firming — that's the rotation. Our full universe (3624 names, incl. international + AI): 54% above 200d, median +5.9% YTD.
Headline check — S&P 500 not above a rising 50-day average, Nasdaq-100 not above a rising 50-day average. Participation broadly tracks the indices.
Participation is contracting across multiple breadth proxies — the market may be shifting from broad advance to narrow leadership or distribution.
Every structural proxy, decomposed. State classifies each ratio's participation trend; the diffusion index weights them by importance. Core ratios (★) drive the confirmation score.
| Ratio | State | 21d | 63d | 252d | z-252 | %ile-252 | DD-252 | d/high |
|---|---|---|---|---|---|---|---|---|
| RSP/SPY★S&P 500 Equal-Weight Breadth | moderate narrowing | -1.6% | +0.3% | -1.2% | -0.34 | 37 | -5.2% | 137 |
| QQQE/QQQ★Nasdaq-100 Equal-Weight Breadth | failed recovery | -2.8% | +0.5% | -1.6% | -0.47 | 31 | -5.1% | 33 |
| QNXT/QTOP★Nasdaq Ex-Top-30 Breadth | strong narrowing | -5.2% | -1.3% | -7.3% | -1.51 | 8 | -10.8% | 237 |
| XMAG/SPY★Ex-Mag-7 Breadth | failed recovery | -1.9% | -1.8% | -0.3% | -0.21 | 49 | -4.7% | 55 |
| SPXT/SPYEx-Tech S&P Breadth | moderate narrowing | -0.0% | +0.8% | -5.0% | -1.31 | 9 | -7.7% | 137 |
| QQXT/QQQNasdaq Ex-Tech Breadth | moderate narrowing | -2.4% | +4.5% | -16.6% | -1.27 | 18 | -19.6% | 116 |
| IWM/SPY★Small-Cap Breadth | moderate narrowing | -4.2% | -3.8% | +3.8% | -0.21 | 39 | -8.5% | 55 |
| MDY/SPYMid-Cap Breadth | strong narrowing | -4.2% | -4.2% | -3.2% | -1.23 | 11 | -7.8% | 136 |
| VXF/SPYExtended-Market Breadth | failed recovery | -3.8% | -2.9% | -2.2% | -0.84 | 19 | -6.4% | 55 |
| IWC/IWMMicro-Cap Breadth | strong broadening | +0.4% | +1.9% | +8.2% | +1.29 | 94 | -1.3% | 52 |
| HYG/LQD★Credit Breadth | strong broadening | +0.2% | +2.6% | +5.4% | +2.08 | 98 | -0.2% | 2 |
| SPHB/SPLV★High-Beta Breadth | moderate narrowing | -2.8% | -7.4% | +29.9% | +1.04 | 77 | -10.0% | 59 |
| XLY/XLPConsumer Risk Breadth | strong narrowing | -3.5% | -5.0% | -12.6% | -1.30 | 7 | -18.4% | 216 |
| XLI/XLUCyclical Breadth | moderate broadening | -2.9% | +1.9% | +13.6% | +1.28 | 91 | -4.5% | 25 |
| KBE/XLUFinancial Risk Breadth | strong broadening | +1.7% | +11.2% | +14.8% | +1.92 | 100 | +0.0% | 0 |
| IWO/IWNSmall Growth Breadth | strong narrowing | -4.6% | -6.6% | -8.0% | -1.70 | 3 | -11.9% | 217 |
| IWF/IWDLarge Growth vs Value | strong narrowing | -1.8% | -6.8% | -17.3% | -1.46 | 7 | -21.5% | 219 |
| Ratio | State | 21d | 63d | 252d | z-252 | %ile-252 |
|---|---|---|---|---|---|---|
| QTEC/QQXTNasdaq Tech vs Ex-Tech | moderate narrowing | -1.1% | -8.3% | +38.5% | +1.22 | 82 |
| SMH/XLKSemiconductor Leadership | moderate narrowing | -4.6% | -12.7% | +31.0% | +0.35 | 55 |
| IGV/XLKSoftware Participation | moderate broadening | +4.9% | +18.7% | -30.7% | -0.44 | 43 |
| FDN/XLKInternet Participation | moderate broadening | +2.9% | +11.4% | -24.0% | -0.74 | 33 |
| AIQ/XLKAI Participation | moderate broadening | +1.4% | -1.4% | -2.4% | -1.12 | 14 |
Each ratio (numerator ÷ denominator, adjusted close) gets a full work-up — trend vs its 20/50/100/200-day averages, momentum over 5/21/63/126/252 days, a log z-score, percentile rank and relative drawdown — and is classified into a participation state. The diffusion index weights each ratio's state by importance; the composite score (0–100) blends the share above their 50-day average, the share with positive quarterly momentum, the diffusion, the median z and the core-ratio confirmation. Hidden breadth weakness fires when SPY/QQQ are positive but the score is weak — participation not confirming the tape.
For information and discussion only — a reading of market internals, not investment advice. Scores are relative and descriptive, on uncalibrated thresholds. Cross-read with Beta Instability, the Money Temperature regime and Cointegration.
FAQ · from the current data · as of 2026-09-15
It reads participation two ways: the absolute tape (of the roughly 500 S&P 500 names, how many are above their moving averages, making new highs vs lows, positive on the year) and a relative-ratio diffusion index across roughly 16 structural proxies for the rotation underneath. Together they catch a narrow bull even while the index looks fine.
As of 2026-09-15, the S&P 500 breadth verdict is "Narrow-to-mixed" — 57% of names are above their 200-day average and the median stock is +8.0% year-to-date.
As of 2026-09-15, the Breadth-of-Breadth Score is 31 out of 100, reading as "Breadth deterioration".
As of 2026-09-15, the diffusion index tracks 17 structural ratios (of which 7 are core, confirmation-weighted).