Key Takeaways
- Measures market momentum via new 52-week highs vs lows.
- Above 50 signals bullish trend; below 50 bearish.
- Uses 10-day SMA for smoother trend analysis.
What is High-Low Index?
The High-Low Index is a technical market breadth indicator that measures overall momentum by comparing the number of stocks hitting new 52-week highs against those reaching new 52-week lows. It provides insight into market strength by focusing on extremes rather than just price movements.
This index is often smoothed using a 10-day simple moving average, which reduces volatility and highlights sustained trends in the market.
Key Characteristics
The High-Low Index captures market breadth and momentum with several key features:
- Range: Values range from 0 to 100, where readings above 50 suggest bullish conditions and below 50 indicate bearish momentum.
- Smoothed Data: The use of data smoothing via a 10-day moving average helps filter noise from daily fluctuations.
- Market Breadth Focus: Unlike price-only indicators, it reflects the number of stocks participating in uptrends or downtrends.
- Trend Confirmation: Sustained readings above 70 signal strong bull markets, while readings below 30 warn of severe downtrends.
- Complementary Tool: Often combined with other indicators like RSI or MACD to improve trading decisions.
How It Works
The High-Low Index is calculated by first determining the daily Record High Percent, which is the ratio of stocks hitting new highs to the total of new highs plus new lows, expressed as a percentage.
Next, a 10-day simple moving average of this percentage is computed to create the High-Low Index, smoothing short-term volatility and emphasizing overall market trends. Traders watch for the index to cross above or below key thresholds, such as 50, to identify potential buy or sell signals.
Examples and Use Cases
Traders and analysts use the High-Low Index to assess market conditions and confirm trend strength. For example:
- Large-cap ETFs: Monitoring the SPY ETF’s High-Low Index can help confirm broad market rallies or warnings of weakness.
- Blue-chip stocks: Investors tracking best large-cap stocks use this indicator to gauge participation across major equity components.
- Sector leaders: Airlines such as Delta may experience shifts in momentum reflected in the High-Low Index, signaling changes in sector health.
Important Considerations
While the High-Low Index provides valuable insight into market breadth, it is less reliable in sideways or choppy markets where new highs and lows balance out frequently. Be cautious relying solely on this indicator without supporting analysis.
Incorporating the High-Low Index alongside fundamental approaches like factor investing and managing idiosyncratic risk can enhance your overall market assessment and trading strategy.
Final Words
The High-Low Index offers a clear snapshot of market momentum by comparing new highs to new lows. Monitor readings above or below 50 to confirm trends and adjust your portfolio accordingly. Consider integrating this indicator with other tools to enhance your market timing decisions.
Frequently Asked Questions
The High-Low Index is a technical indicator that measures market momentum by comparing the number of stocks hitting new 52-week highs to those hitting new 52-week lows. It helps gauge overall market health by revealing whether advancing stocks outnumber declining ones.
It is calculated by first finding the Record High Percent, which is the ratio of new highs to the total of new highs plus new lows, expressed as a percentage. Then, this value is smoothed using a 10-day simple moving average to produce the High-Low Index.
A value above 50 indicates bullish market conditions where more stocks are reaching new highs than lows, confirming an uptrend. Sustained readings above 70 signal a strong bull market with broad participation.
When the index falls below 50, it suggests bearish market momentum with more stocks hitting new lows than highs, confirming a downtrend. Values below 30 indicate a strong bearish market.
Traders often look for the High-Low Index crossing above 50 or its 20-day SMA as a buy signal and crossing below as a sell signal. It can also help identify trend reversals when the index diverges from price movements.
Smoothing with a 10-day simple moving average reduces volatility in daily data, making it easier to identify sustained trends and avoid false signals caused by short-term fluctuations.
Yes, divergences between the High-Low Index and price action — such as prices rising while the index falls — can warn of potential market reversals, helping traders anticipate changes in trend direction.


