what is the relative strength index rsi 
the relative strength index rsi is a momentum indicator used in technical analysis rsi measures the speed and magnitude of a security s recent price changes to evaluate overvalued or undervalued conditions in the price of that security the rsi is displayed as an oscillator a line graph on a scale of zero to 100 the indicator was developed by j welles wilder jr and introduced in his seminal 1978 book new concepts in technical trading systems 1the rsi can do more than point to overbought and oversold securities it can also indicate securities that may be primed for a trend reversal or corrective pullback in price it can signal when to buy and sell traditionally an rsi reading of 70 or above indicates an overbought situation a reading of 30 or below indicates an oversold condition 