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The advance-decline ratio, breadth divergence, and why a rising index can lie
Published by The Retail Trader · AUG 09, 2026 · Features
Has it ever happened that the Nifty closed 80 points up, and your whole portfolio was in the red? And you felt the mistake was in your stock selection? Often the mistake is not in selection — the market really had not gone up that day. Only the index had gone up. The name for the difference between the two is breadth.
The Nifty's 50 stocks are not counted equally. Each stock's weight is based on its free-float market capitalisation, and the few biggest names together control more than half of the whole index. The exact weights change at every rebalance, but the principle stays the same.
The direct result: if the three or four heaviest stocks rise 2% in a day, the index can close green even if the other 45 stocks are falling. The index did not lie — it simply answered a question that you thought you had asked but had not.
Advance-decline (A/D) simply counts how many stocks closed up and how many closed down that day. The exchange publishes this daily.
How to read it:
• A/D ratio above 2:1 — more than two risers for every faller. This is a healthy, broad-based day. There is participation in the rally.
• A/D ratio around 1:1 — the market has not made up its mind. Whatever the index is doing, a tug-of-war is going on inside.
• A/D ratio below 1:2 — the fall is broad. If the index is still green on such a day, that green belongs to a few heavyweights, not the market.
One day's A/D is noise. A pattern across five to seven consecutive sessions is a signal.
Divergence means: the index is making a new high, but the number of stocks closing up shrinks with every rally. That is, the same climb rests on fewer and fewer shoulders.
This by itself is not a sell signal — divergence can run for a whole month and the market can still keep going up. Its job is different: it tells you which way risk is increasing. In a broad rally you can make money even by picking the wrong stock. In a narrow rally you do not make money even by picking the right stock.
The reverse also happens, and it is more useful: the index is still going down but advancing stocks begin to increase — meaning the internal decline has started to stop, while the heavyweights are still dragging the index down.
The percentage of stocks closing above the 200-day moving average is the long version of breadth. 70%+ means broad strength in the market. Below 30% means most stocks are below their long-term trend — even if the index still looks only slightly down.
This number does not change daily, so watching it daily is pointless. Looking once a week is enough, and that gives the temperature of the whole market.
One more layer: how many sectors are participating. If only one sector is running and the rest are flat or red, that is not a market rally — it is one sector's move that has shown up in the index.
That is why a glance at sector-wise performance at the end of the day is more informative than looking at the index level. If six out of eight sectors are green, that is a real rally. If one out of eight, that is a theme.
A two-minute daily check, after the market closes:
• How many advanced and how many declined today — and whether this is better or worse than the last four days.
• Whether the index move came from heavyweights or from broad participation.
• How many sectors closed green.
Together these three answers give you what the index chart alone will never give: knowing how many people carried today's move. And a move carried by few people also takes less time to break.
This article is for educational purposes only — it is not a buy or sell recommendation, makes no claim of guaranteed returns, and is not advisory. Rules, rates and mechanics are changed by the exchange, SEBI and RBI from time to time, so verify every number yourself with your broker or an official source.