J. Welles Wilder Jr.

J. Welles Wilder Jr. trained as a mechanical engineer before becoming a commodity trader and technical analyst in the 1970s. In 1978 he published 'New Concepts in Technical Trading Systems,' a groundbreaking book that introduced five technical indicators that have since become the most widely used analytical tools in all of financial markets: the Relative Strength Index (RSI) for measuring momentum and overbought/oversold conditions; the Average True Range (ATR) for measuring volatility; the Parabolic SAR for trailing stop placement; the Directional Movement Index (DMI) and Average Directional Index (ADX) for measuring trend strength. The extraordinary density of innovation in a single publication — five major indicators, each with practical trading rules — has no parallel in the history of technical analysis. Wilder used relatively straightforward mathematics compared to much later quantitative finance work, which made his indicators accessible to practitioners without advanced mathematics. All five indicators are now standard in every charting software from Bloomberg Terminal to mobile trading apps, and are used by hundreds of millions of traders and investors globally. Wilder passed away in 2021.