What Is Mean Reversion in Stocks?
Mean reversion in stocks is the idea that a price that has moved far from its own recent average tends to move back toward it. It is a statistical tendency, not a rule: a stock that looks cheap against its average can keep falling for weeks.
This site's Mean Reversion Screener measures how stretched a price is, and its own forward log shows the misses. Nothing here is a buy signal.
What does the screener actually measure?
It tests five conditions, each true or false today, and counts how many are true. The count is a plain tally, not a weighted score. A stock appears if at least one holds. The method page has the rules, and the last column shows how many of the 52 stocks on the list met each as of October 23, 2026:
| Condition | Rule | Stocks meeting it |
|---|---|---|
| RSI | 14-day RSI below 30 | 19 |
| Stretched below trend | At least 15% below the 20-day average (SMA) | 16 |
| Below the band | Under the lower Bollinger Band (%B below 0) | 31 |
| Volume exhaustion | Volume at least 2 times its 30-day average | 6 |
| Near the low | Within 1.5% of the 52-week low | 8 |
Of the 52 stocks, 33 meet one condition, 12 meet two, 5 meet three and 2 meet four. The conditions overlap, so a higher count is not five independent confirmations. The page also shows a 2-day RSI as a column, but it is not one of the five.
Does mean reversion actually work?
Sometimes. The site records every new signal on the day it appears and checks it 10 trading days later: did the stock close up 5% or more at any point? It compares that with the same test on every stock in the universe, on the same dates.
Share closing up 5% or more at some point within 10 trading days, from the forward log on the mean reversion page. The all-stocks group is the whole universe (501 to 503 stocks per date).
The result is mixed, and it is only three signal dates. The September 18 group did worse than the market as a whole; the October 7 and 9 groups did better. Taken together, 36.7% of signalling stocks had a 5% close against 43.0% of all stocks, and their median day-10 return was -1.26% against +1.91%.
The cohorts overlap and the market moved between them, so this says little about the long run. What it does show is that a stretched price is not a reliable bounce. The page itself says a short track record is not a verdict.
Why can a cheap stock keep getting cheaper?
A price far below its average can mean a temporary overreaction, or that the business changed. The chart cannot tell you which. That is why the screener adds seven falling-knife checks on debt, liquidity, profit, interest cover, sales, drawdown and insider selling.
- 37 of the 52 signalling stocks tripped at least one of the seven checks; 15 tripped none.
- Howmet (HWM) met four conditions with no guardrail flags, but reports earnings within days, which the page flags as event risk.
- KLA (KLAC) met three conditions and carries two guardrail flags.
For the fundamentals side of the question, read how to check if a stock is a value trap. For the indicator itself, what RSI below 30 means.
What is the difference between mean reversion and a breakout?
| Approach | Assumes | Typical reading | Where it fails |
|---|---|---|---|
| Mean reversion | A stretched price returns to its average | Far below a moving average, low RSI | The move was a real change, so the average moves instead |
| Breakout | A price leaving its range keeps going | A new high on volume | The move fades back into the range |
Both read the same price move and expect opposite things, which is a reason to treat either as a hypothesis. See mean reversion in the glossary. This is educational analysis, not investment advice.
Mean reversion FAQ
Is mean reversion a reliable trading strategy?
It is a statistical tendency with failures, not a reliable rule. A stock can stay stretched or keep falling, and this site's own forward log of 60 resolved signals does not show the signalling stocks beating all stocks.
What is the difference between mean reversion and a breakout?
Mean reversion assumes a price stretched far from its average moves back toward it. A breakout strategy assumes a price leaving its range keeps moving in that direction. They are opposite readings of the same move.
Does the screener use standard deviations from a moving average?
Partly. One of the five conditions is Bollinger %B, which measures price against bands set two standard deviations around the 20-day average. The others are RSI(14), distance below the 20-day average, volume and nearness to the 52-week low.
Is an oversold stock a buy?
No. Oversold describes how far a price has fallen, not why. A stock can be oversold and also unprofitable, heavily indebted or in decline.
How do I tell a dip from a falling knife?
Check the business, not the chart. The screener runs seven checks on debt, liquidity, profit, interest cover, sales, drawdown and insider selling, and 37 of the 52 signalling stocks tripped at least one.