Market Breadth Dashboard

S&P 500 Stock Participation & Market Strength Analysis

This dashboard analyzes breadth data for the S&P 500 stocks. Market breadth measures the participation of stocks in a market move. While the S&P 500 index can be driven by a handful of large-cap stocks, breadth reveals the true health of the market by showing how many of the 500+ stocks are actually advancing. Track advance/decline ratios, moving average breadth, 52-week highs vs lows, and cumulative breadth indicators to understand market momentum and identify potential turning points.

Open Source & Transparent

All data is open source and verifiable on GitHub. We believe in transparency and welcome contributions to improve our tools.

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Understanding market breadth

Breadth answers a simple question: is the market move broad-based, or driven by a handful of names? Use these signals as context for risk and regime awareness, not as a standalone timing tool.

General overview: what breadth is measuring

This page measures participation across the ~500 S&P 500 constituents. Index prices can rise even when most stocks are falling, because the index is market-cap weighted. Breadth helps you see beyond that.

Stronger breadth (more advancers, more stocks above key moving averages, more new highs) typically supports a healthier uptrend. Weak breadth can flag fragility even if the index is near highs.

The best use is confirmation: does participation agree with the price trend, or are you seeing divergences?

Detailed breakdown: how to interpret the main signals

These cards summarize the most common breadth inputs and the practical takeaways they can support.

Breadth confirmation workflow

Price trend + Participation trend → Higher confidence regime read

Start with the index trend, then confirm whether participation is improving or deteriorating. If breadth diverges from price for an extended period, treat it as a risk flag and tighten risk management.

A/D

Advancers vs decliners

%>MA

Trend participation

52W

Leadership check

Tip: pair this with Market Snapshot for a broader cross-asset view.

Advance/decline ratio

Are more stocks rising than falling?

  • Above 2:1 is often read as strong breadth confirmation.
  • Below 1:1 means more decliners than advancers (risk-off participation).
  • Watch for: breadth weakening while index rises (divergence).

Percent above moving averages

Trend participation across timeframes

  • 20-day is short-term momentum; 50-day is intermediate; 200-day is long-term regime.
  • 70%+ indicates broad strength; 30%− can indicate oversold participation.
  • Use it for: confirming trend strength rather than calling tops/bottoms.

52-week highs vs lows

Leadership and breakdowns

  • More highs suggests stronger leadership and momentum; more lows suggests distribution.
  • A high/low ratio above ~2:1 is typically constructive.
  • Divergence watch: new index highs with few new highs can be a caution signal.

Cumulative A/D line

Participation over time

  • Rising A/D line confirms improving participation.
  • Falling A/D line while index rises can signal narrowing leadership.
  • Bullish divergence can appear when A/D improves before price bottoms.

Frequently asked questions

What is market breadth and why does it matter? ▼

Market breadth measures how many stocks are participating in a market move. While major indexes can be driven by a few large-cap stocks, breadth reveals the true health of the market by showing if most stocks are advancing or declining. Strong breadth (70%+ of stocks above moving averages) indicates a healthy, sustainable trend, while weak breadth (below 30%) suggests vulnerability even if indexes are rising.

How do I interpret the advance/decline ratio? ▼

The advance/decline ratio shows the number of advancing stocks divided by declining stocks. A ratio above 2:1 indicates strong bullish breadth with more than twice as many stocks rising as falling. Ratios between 1:1 and 2:1 show moderate strength, while ratios below 1:1 (more stocks declining than advancing) indicate bearish conditions. Sustained high ratios confirm rally strength.

What does it mean when stocks are above their moving averages? ▼

The percentage of stocks above moving averages measures trend strength. Above 70% indicates a strong uptrend with broad participation. 50-70% shows moderate bullish conditions. Below 50% means more stocks are in downtrends than uptrends. Below 30% indicates very weak market conditions and potential oversold levels. The 20-day MA tracks short-term trends, 50-day shows intermediate trends, and 200-day reflects long-term bull/bear market conditions.

How should I use 52-week highs and lows data? ▼

When over 10% of stocks are near 52-week highs, it indicates strong leadership and healthy market momentum. Over 10% near lows suggests broad weakness. The high/low ratio above 2:1 is bullish (more stocks leading higher than breaking down). Watch for divergences: if the index hits new highs but few stocks participate (low percentage near highs), it signals potential trend exhaustion.

What is the advance-decline line telling me? ▼

The cumulative advance-decline (A/D) line is a running total of daily net advances minus declines. A rising A/D line confirms that more stocks are participating in rallies - a healthy sign. A declining A/D line while indexes rise (bearish divergence) warns of narrowing leadership and potential reversal. When the A/D line rises while indexes fall (bullish divergence), it can signal an upcoming rally as breadth improves.

Important considerations

  • Breadth can stay extreme — overbought/oversold participation can persist in strong trends.
  • The index is cap-weighted — mega-caps can mask weak breadth for long stretches.
  • Not financial advice — use breadth as context alongside your own risk management.

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