The phrase "upper band" refers to the highest limit or boundary of a certain range or measurement. It is used to describe the uppermost level or range of something. Full definition
Cover and go short when daily closing price crosses above upper band. (babypips.com)
Taken together, these results suggest that funds with loss rates near the lower or upper bands of the 35 % -70 % range tend to underperform because they take too little or too much risk, respectively. (industryventures.com)
Created by John Bollinger in the 1980s, Bollinger bands create a low, middle, and upper band based on the volatility and moving average of the stock. (personalprofitability.com)