Our coverage of open interest has concentrated on the futures markets. Open interest plays an important role in options trading as well. Open interest figures are published each day for put and call options on futures markets, stock averages, industry indexes, and individual stocks. While open interest in options may not be interpreted in exactly the same way as in futures, it tells us essen­tially the same thing—where the interest is and the liquidity. Some option traders compare call open interest (bulls) to put open interest (bears) in order to measure market sentiment. Others use option volume.market.