What is the RSI
The Relative Strength Index (RSI) is a momentum oscillator used in the technical analysis of financial
markets to evaluate the current and historical strength or weakness of a stock or market based on
closing prices over a recent trading period. It measures the speed and magnitude of directional price
movements by calculating momentum as the ratio of higher closes to lower closes. A higher RSI
indicates stronger positive changes, while a lower RSI indicates stronger negative changes. Typically,
the RSI is calculated over a 14-day period and is scaled from 0 to 100, with 70 and 30 commonly used
as high and low levels, respectively. More extreme levels, such as 80 and 20 or 90 and 10, indicate
stronger momentum.
Configuration
The RSI is displayed on a graph above or below the price chart, featuring an upper line at 70, a lower
line at 30, and a dashed mid-line at 50.
Principles
When prices rise quickly, they are considered overbought, and when they fall rapidly, they are
considered oversold. An RSI above 70 suggests overbought conditions, while an RSI below 30 suggests
oversold conditions. Values between 30 and 70 are considered neutral, with 50 indicating no trend.
Divergence
Divergence between RSI and price action signals a potential market turning point. Bearish divergence
occurs when the price makes a new high but the RSI makes a lower high. Bullish divergence occurs
when the price makes a new low but the RSI makes a higher low.
Overbought and oversold conditions
“Failure swings” above 70 and below 30 on the RSI are strong indicators of market reversals. For
example, if the RSI hits 76, drops to 72, then rises to 77, and subsequently falls below 72, this is
considered a “failure swing” above 70. Support and resistance levels are often easier to identify on
the RSI chart than on the price chart. The 50 level serves as a support and resistance line for the RSI,
indicating whether gains or losses are greater.
Uptrends and Downtrends
RSI interpretations have evolved to help determine and confirm trends. In uptrends, RSI values
typically range between 40 and 80, while in downtrends, they range between 20 and 60. When securities transition between uptrends and downtrends, the RSI undergoes a “range shift.” Bearish
divergence occurs only in uptrends and usually indicates a brief correction, confirming the uptrend.
Conversely, bullish divergence occurs only in downtrends and confirms the downtrend.
Reversals
Positive and negative reversals in the RSI are the opposite of divergence. A positive reversal occurs
when a higher low in price is accompanied by a lower low in RSI during an uptrend correction. A
negative reversal happens when a lower high in price is accompanied by a higher high in RSI during a
downtrend rally. Positive reversals occur only in uptrends, and negative reversals occur only in
downtrends, confirming the respective trends.