Learn what the relative strength index (RSI) is, how it works, and how to read overbought and oversold signals, along with the formula behind this popular indicator.

How the Relative Strength Index (RSI) Works As a momentum indicator, the relative strength index compares a security's strength on days when prices go up to its strength on days when prices go down.

What is RSI (Relative Strength Index)? RSI (Relative Strength Index) is counted among trading's most popular indicators. This is for good reason, because as a member of the oscillator family, RSI can ...