The On-Band Volume (OBV) indicator measures the strength of capital inflows and outflows by analyzing the relationship between volume and price, thereby capturing changes in market sentiment and trends. Its core idea is that effective price changes must be accompanied by an increase or decrease in volume. When prices rise and volume increases, OBV rises, indicating that there is buying momentum in the market and the trend may continue; when prices fall and volume increases, OBV falls, indicating that there is selling pressure in the market and the trend may continue; if prices rise but OBV does not rise synchronously, it may mean that the sustainability of the upward trend is weak, which may indicate the risk of a trend reversal; and vice versa. Compared with simply observing volume, OBV can more clearly show market momentum by accumulating volume and taking into account price direction, which helps to identify potential changes in trends and detect price reversal signals in advance. Therefore, OBV is often used to assist other technical analysis indicators to improve the accuracy of trading decisions.