Relative Strength (Stock vs Index)
A measure of a stock's price performance relative to a benchmark index such as Nifty 50, used to identify securities that are outperforming or underperforming the broader market on a sustained basis.
Relative strength (RS) analysis, distinct from the RSI oscillator, compared a stock's price performance to its benchmark index by dividing the stock price by the index level and plotting the resulting ratio as an RS line over time. When the RS line was rising, the stock was outperforming the index; when it was falling, the stock was underperforming. A stock in a genuine bull trend alongside a rising RS line was considered in a fundamentally stronger position than a stock rising only because the broader market was rising.
The Mansfield Relative Strength was a normalised variant developed by Stan Weinstein and popularised in his book on stage analysis. It expressed the RS ratio relative to a 52-week moving average of the ratio, making it easier to compare RS levels across stocks with different price histories. A Mansfield RS above zero indicated the stock had outperformed the benchmark over the past year; below zero indicated underperformance.
In Indian markets, RS analysis was applied primarily using Nifty 50 as the benchmark for large-cap stocks and Nifty 500 for broader market comparisons. Sectoral RS — comparing a sector index such as Nifty IT or Nifty Pharma to Nifty 50 — provided a macro lens on which sectors were leading and lagging at any given phase of the market cycle.
The analytical principle often cited was to focus on stocks with strong RS during market corrections. If Nifty fell 10% in a correction and a particular stock fell only 2% or held flat, its RS line improved dramatically during the decline, indicating institutional accumulation or fundamental business strength. Historically, stocks that showed RS strength during corrections often led the subsequent recovery rally.
William O'Neil, whose CANSLIM methodology was widely studied in Indian growth-stock investing circles, emphasised that his RS Rating (a 1-99 scale ranking each stock against all others) was one of the most predictive factors for identifying future price leaders. Stocks with RS Rating above 80 at the time of a valid base breakout historically showed higher average subsequent returns than stocks with lower RS ratings.