Wilder originally developed the ATR for commodities, although the indicator can also be used for stocks and indices.1 Simply put, a stock experiencing a high level of volatility has a higher ATR, and a lower ATR indicates lower volatility for the period evaluated.
The ATR may be used by market technicians to enter and exit trades and is a useful tool to add to a trading system. It was created to allow traders to more accurately measure the daily volatility of an asset by using simple calculations. The indicator does not indicate the price direction; instead, it is used primarily to measure volatility caused by gaps and limit up or down moves. The ATR is relatively simple to calculate, and only needs historical price data.
The ATR is commonly used as an exit method that can be applied no matter how the entry decision is made. One popular technique is known as the “chandelier exit” and was developed by Chuck LeBeau. The chandelier exit places a trailing stop under the highest high the stock has reached since you entered the trade. The distance between the highest high and the stop level is defined as some multiple multiplied by the ATR.
The ATR can also give a trader an indication of what size trade to use in the derivatives markets. It is possible to use the ATR approach to position sizing that accounts for an individual trader’s willingness to accept risk and the volatility of the underlying market.