Defining Overbought and Oversold Conditions in Stock Market Trading
We define the overbought condition as the point in which the stock price has gone through an upward trajectory so aggressively that market participants now consider it too expensive relative to its historical worth. The buying pressure has been so intense that the momentum is now more likely to decelerate or experience a reversal. In practice, the bullish trend reaches a maturity point where the capital needed to push prices forward starts to wane down.
The market is considered oversold when the inverse happens. The stocks go through a period of violent selling pressure in which prices drop below its perceived intrinsic value. The downtrend starts losing strength and additional amounts of capital are required to bring prices even lower.
Market conditions like these, where prices remain overbought or oversold for extended periods, are a result of extreme sentiment. Either caused by euphoria or panic. When the pressure dissipates, the market may have reached a ceiling or a floor. In this case, institutional players start developing their next move, since there’s a mathematical bargain in betting that prices will revert back to the mean, away from the extremes.
Reading Market Conditions with Key Indicators
Both technical indicators and fundamental analysis work when checking whether prices might be considered overbought or oversold. Below, a table displays how you would typically evaluate and define market conditions according to each type of analysis.
|
Technical Analysis |
Fundamental Analysis |
| Primary Metrics |
Price action and momentum oscillators |
Earnings, revenue, and debt-to-equity |
| Overbought Definition |
RSI > 70 or Stochastic > 80 |
High P/E or price-to-sales ratios |
| Oversold Definition |
RSI < 30 or Stochastic < 20 |
Trading below book value or cash flow |
| Time Horizon |
Short-to-mid term trading |
Long-term investment |
Although fundamental analysis gives useful indicators for highlighting overbought and oversold conditions, most traders rely mainly on technical trading, focusing on potential market reversals for short-to-mid term opportunities.
The RSI and the Stochastic Oscillator, which we’ll explore further down below, are among the most popular technical indicators for this type of strategy.
Relative Strength Index (RSI)
The RSI is an indicator that measures the magnitude and speed of recent price changes as a way to evaluate the strength of the broader trend. J. Welles Wilded developed in the 80s, and it has been used across several markets since then.
The mathematical reading normalizes the data into a scale from 0 to 100. A reading above 70 classifies the stock as overbought. Readings below 20 classify it as oversold.
Traders use RSI levels to detect when prices reach overbought or oversold conditions, but they can also use RSI readings to monitor momentum divergence, which happens when price makes new highs, but the indicator prints a lower high. This is a sign that the uptrend might be reaching its exhaustion point, even before prices starts to show signs of weakness.
The Stochastic Oscillator
The Stochastic Oscillator differs from the RSI in the sense that it measures the velocity of price relative to its high-low range over a defined period.
This indicator follows the assumption that, during strong trends, prices should cluster near the top of the recent range for bullish momentum or at the bottom for bearish momentum.
A reading above 80 indicates that prices are closing within the top 20% of the last n number of trading periods and implies the stock is under overbought conditions.
For oversold conditions, readings below 20 exposes the fact that the price is orbiting the bottom 20% of the last n days.
Traders, in general, combine the stochastic indicator with other tools to better interpret a signal before opening a premature position. An entry is triggered when the fast %K line crosses above the slow %D line while in an extreme oversold zone, for example.
It’s very hard to gain advantage from technical analysis from one single indicator. Successful traders don’t rely only on the RSI or Stochastic Oscillator to compare trends and formulate market thesis. They take advantage of a combination between these and supplementary tools.
The MACD, for example, is a great ally when considering broader market momentum. When the histogram expands away from zero, either up or down, it indicates that market pressure is strong. The furthest away from zero, the stronger the trend is.
The Average Directional Index (ADX) is yet another indicator traders use to capture the strength of a trend, regardless of its direction. Market players can use it to understand whether market is in range-bound sideways conditions in the longer run, which can be helpful in avoiding trend-following strategies where there is no real trend determining the course of action.
Bollinger Bands, on the other hand, has a volatility-based approach. It can be also used to identify overbought and oversold conditions. When prices pierce the upper band, they’re technically too expensive relative to their mean. The same is valid when prices touch the lower band.
Comparing the RSI vs Stochastic Oscillator outputs alongside Bollinger Bands can be a great addition to identify overbought and oversold zones with even higher precision.
Bullish or Bearish? How to Identify the Main Trend and Take Advantage of It
The main factor when it comes to trading financial markets is whether you can understand broader market context or not. An oscillator is completely blind to macroeconomic events. It is simply calculated data over an n look-back period.
Although it does give you relevant information, it cannot tell you whether the market is trending or walking sideways in the long-term. It’s up to you to define what is the current regime.
If the market is indeed trending, the asset can remain overbought or oversold for an extended period. An RSI of 85 during bullish euphoria confirms the strength, instead of immediately signaling for a reversal.
- Uptrend and Downtrend tip: If trading along with the trend is your strategy, you should only seek for entry points on temporary dips or relief rallies for buying or opening short positions.
In range-bound markets, prices tend to revert to the mean. In this case, overbought and oversold indicators can help you achieve the highest efficacy for profits. As a rule of thumb, when the RSI approaches 70 and prices are swinging around a horizontal resistance, you can start considering the possibility of a downward pressure.