--- title: "Mean reversion or momentum: what is the difference?" description: "Momentum bets that a move keeps going, and mean reversion bets that a stretched price returns toward its average." source_url: "https://www.rupeecase.com/learn/questions/mean-reversion-vs-momentum" --- One Nifty path holds a rise, a fall, a rebound and a drift lower, so the path alone does not name a style Daily close of the Nifty 50 from 2 Feb to 10 Jun 2026: a rise to 11 Feb, a fall to 30 Mar, a rebound to 21 Apr and a drift lower. Momentum and mean reversion are rules, and each needs a lookback, a threshold and a holding period before it can be tested. Source: NSE end of day data, computed by RupeeCase. As of 10 Jun 2026. Both ideas start from one observation: prices move in runs, and they also snap back. Momentum says that a stock or index that has risen over a lookback period tends to keep rising over the next holding period. Mean reversion says that a price stretched far from its average tends to come back toward it. The chart is one path of the Nifty close. It holds a short rise, a long fall, a rebound and a drift lower, so each style can be found in some stretch of it. The path alone does not say which style is at work. That depends on the lookback, the threshold and the holding period you choose, and a different choice can flip the answer. A fair test fixes those three choices before it looks at results, then runs them on data the rule did not see when it was built. That is the out of sample test. Many rules pass on the period that shaped them and fail on the next, so a result that depends on a finely tuned lookback is a warning, not a finding. Options add a twist. A buyer who takes a position after a rise is betting on momentum with the premium paid up front. A seller who takes a position after a pull back is betting on reversion, with the loss open at the far end. The style sits in the rule and the payoff, not in the chart. **Before you trade.** Derivatives trading carries a high risk of loss. SEBI's study "Profitability of Individual Traders in the Equity Derivatives Segment (FY25 to FY26)" (August 2026) found that 87.7% of individual traders in equity F&O made net losses in FY26, with aggregate net losses of Rs 91,685 crore. [Read the SEBI study](https://www.sebi.gov.in/reports-and-statistics/research/aug-2026/study-profitability-of-individual-traders-in-the-equity-derivatives-segment-fy25-fy26-_103835.html) Mean reversion or momentum: what is the difference?Momentum bets that a move keeps going, and mean reversion bets that a stretched price returns toward its average, so the two give opposite answers to the same question about the last move. Both can look right on one chart, which is why a fair test needs a fixed rule, a holding period and data the rule did not see. LGo deeper ## Where Learn teaches this. [Go deeperMean reversion against momentum10 min, Advanced](/learn/path-18/module-18-9-mean-reversion-vs-momentum) SSources ## Go to the source. 1. [SEBI investor education, Understanding derivatives](https://investor.sebi.gov.in/understanding_derivatives.html) SEBI ?Questions people ask ## Related questions. 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