John Bollinger is an American financial analyst and fund manager, best known for creating the Bollinger Bands trading tool. This tool helps traders identify market volatility and potential price movements by using a set of lines plotted above and below a moving average. Bollinger has authored several books on technical analysis and trading strategies, contributing significantly to the field of finance. He is also the founder of Bollinger Capital Management, a firm that provides investment management services. His work has influenced many traders and investors in understanding market dynamics.