Absolute Breadth Index

In the world of finance and investing, there are numerous indicators and indices used to gauge the health and direction of the stock market. One such tool that has gained popularity among traders and analysts is the “Absolute Breadth Index” (ABI). Market breadth is a crucial concept in assessing the overall strength of a market, and the ABI provides valuable insights into the participation and momentum of stocks in a given market. In this article, we will delve into the concept of market breadth, explain what the Absolute Breadth Index is, how it’s calculated, and its significance in making informed investment decisions.

Absolute Breadth Index
Absolute Breadth Index

Market Breadth: The Pulse of the Market

Before delving into the Absolute Breadth Index, it’s essential to understand the concept of market breadth. Market breadth refers to the extent to which stocks are participating in a market’s movement. It provides a broad view of the overall market by measuring the number of advancing and declining stocks and comparing them to the total number of stocks traded.

Market breadth indicators offer a different perspective from traditional price-based indicators, such as the Dow Jones Industrial Average (DJIA) or the S&P 500 Index. While these price-based indicators focus on the performance of a specific group of stocks, market breadth considers the collective strength of all stocks traded on a given exchange.

Introduction to the Absolute Breadth Index (ABI)

The Absolute Breadth Index is one of the essential tools used to measure market breadth. It was developed by Norman G. Fosback and introduced in his book “Stock Market Logic” in 1976. The ABI is a simple yet powerful indicator that quantifies the volatility and momentum of the market.

At its core, the Absolute Breadth Index calculates the absolute difference between the number of advancing and declining stocks. It is essentially the net number of stocks moving up or down on a particular trading day.

Calculating the Absolute Breadth Index

The calculation of the Absolute Breadth Index involves four primary steps:

Step 1: Measure Advancing and Declining Stocks On any given trading day, the number of stocks that closed higher (advancing) and the number of stocks that closed lower (declining) are recorded.

Step 2: Calculate the Difference Subtract the number of declining stocks from the number of advancing stocks. The result will be a positive or negative number.

Step 3: Take the Absolute Value Regardless of whether the result from Step 2 is positive or negative, take the absolute value of that number (i.e., remove the negative sign if present).

Step 4: Sum the Absolute Differences Repeat this process for each trading day over a specific period (e.g., 10 days, 50 days, or 200 days), and then sum up all the absolute differences to get the Absolute Breadth Index value for that period.

Interpreting the Absolute Breadth Index

The Absolute Breadth Index provides traders and analysts with valuable insights into the market’s internal strength and momentum. Here’s how to interpret the ABI:

a. High ABI Values A high Absolute Breadth Index value indicates a robust and healthy market. It suggests that a large number of stocks are actively participating in the market’s upward movement. In such conditions, the overall market trend is considered to be strong, and traders may find more opportunities to capitalize on bullish trends.

b. Low or Negative ABI Values Conversely, a low or negative Absolute Breadth Index value suggests a market with weak internal participation. It means that the majority of stocks are not moving in unison, and the market’s trend may be losing momentum. In such situations, caution is advised as the market could be prone to increased volatility and potential reversals.

c. Divergence with Price-based Indicators One of the most significant advantages of the Absolute Breadth Index is its ability to identify divergences with traditional price-based indicators. If the market is reaching new highs, but the ABI is showing a declining trend, it could be a sign of weakening market breadth, which may precede a market correction or bearish reversal. Conversely, if the market is declining, but the ABI is rising, it might indicate that the overall market sentiment is not as bearish as the price-based indicators suggest, potentially signaling a bullish reversal.

Using the Absolute Breadth Index in Trading Strategies

The Absolute Breadth Index can be a valuable tool in developing trading strategies. Here are some ways traders and analysts incorporate ABI into their decision-making process:

a. Confirming Trends When the ABI is in agreement with the direction of the market’s major indices, it confirms the strength of the prevailing trend. This alignment can provide traders with added confidence in their positions.

b. Identifying Reversals As mentioned earlier, divergences between the ABI and price-based indicators can be powerful signals for potential market reversals. Traders may use this information to adjust their positions or implement contra-trend strategies.

c. Assessing Market Health By monitoring the Absolute Breadth Index regularly, traders and investors can gauge the overall health of the market. A consistently high ABI suggests a robust and vibrant market, while a declining ABI may indicate a weakening market.

d. Setting Stop-loss Levels The ABI can also assist in setting stop-loss levels. During periods of low ABI values, it may be prudent to set tighter stop-loss orders to protect against increased volatility and sudden price swings.

Limitations of the Absolute Breadth Index

While the Absolute Breadth Index is a valuable tool, it is essential to recognize its limitations to avoid misinterpretation and erroneous conclusions:

a. Lack of Context The ABI only measures the net difference between advancing and declining stocks without considering the total number of stocks traded or their individual market capitalizations. As a result, it may not provide a comprehensive view of the entire market.

b. Short-term Volatility The Absolute Breadth Index can be sensitive to short-term fluctuations in the market, potentially generating false signals. Traders should consider using longer time frames or combining the ABI with other indicators to filter out noise and improve accuracy.

c. Not a Standalone Indicator While the ABI offers valuable insights, it is not meant to be used in isolation. Traders and analysts should consider using it in conjunction with other technical and fundamental analysis tools for a well-rounded assessment.


The Absolute Breadth Index is a powerful tool that provides valuable insights into market breadth and momentum. By measuring the net difference between advancing and declining stocks, the ABI helps traders and analysts gauge the overall health of the market and identify potential reversals.

When used in conjunction with other indicators and analysis techniques, the Absolute Breadth Index can significantly enhance the decision-making process for traders and investors. However, like any financial indicator, it is essential to understand its limitations and avoid relying solely on its signals.

As with all investment-related decisions, traders should conduct thorough research, use a disciplined approach, and consider their risk tolerance before incorporating the Absolute Breadth Index into their trading strategies. By doing so, they can harness the power of market breadth analysis and make more informed investment choices.

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