SPX Cumulative AD Line Indicator

The Other ADLines online are trash. Use this one.

This indicator, written in Pine Script version 6, is designed to track market breadth for the S&P 500 by constructing and analyzing a cumulative Advance-Decline (AD) Line. It begins by allowing the user to set two parameters: a smoothing length for the AD line itself and a moving-average length (defaulted to 50 weeks) that will later be applied to the smoothed line. These inputs let traders tailor the sensitivity of the indicator to their preferred timeframe and trading style.

To build the AD line, the script pulls real-time S&P 500 index prices as well as the number of advancing and declining stocks using dedicated market breadth tickers. It calculates the daily AD difference by subtracting declines from advances, a classic method for measuring participation across the index. This difference is fed into a cumulative calculation, which produces a running total that tracks whether market participation is strengthening or weakening over time.

The cumulative AD line is then smoothed with a simple moving average based on the user’s specified smoothing length. At the same time, the script dynamically converts the 50-week moving-average period into an equivalent value for whatever chart timeframe is being used—intraday, daily, weekly, or monthly. This ensures that the moving average of the AD line reflects a consistent long-term trend regardless of the chart’s resolution.

Next, the smoothed AD line is compared to its converted 50-week moving average to determine the market’s directional bias. When the AD line rises above its long-term average, the script labels the environment as bullish; when it falls below, it flags a bearish environment. It also detects crossovers between the two lines, generating discrete buy signals when the AD line crosses upward and sell signals when it crosses downward.

Finally, the indicator visualizes all elements on the chart: the smoothed AD line, its long-term moving average, a zero reference line, and the buy/sell markers. It also colors the line and background to reflect bullish or bearish conditions, making shifts in market breadth easy to spot at a glance. This provides traders with a comprehensive breadth-based tool for identifying trend strength and potential reversals in the S&P 500.