A measure of investor sentiment in the market measured by looking at the number of opening long call options to opening long put options purchased on the International Stock Exchange. The measure only considers the purchases of customers and does not include the purchases made by market makers, as customers are thought to be the best measures of sentiment. If the value of the indicator is above 100, it means that more long call options have been purchased by investors than long put options. If the indicator is below 100, it means that more long puts have been purchased compared to long calls. The higher the index is above 100, the more bullish the market sentiment is thought to be, with measures below 100 signaling bearish sentiment.