Looking at options trading activity among components of the S&P 500 index, there is noteworthy activity today in Exxon Mobil Corp (XOM), where a total volume of 66,302 contracts has been traded thus far today, a contract volume which is representative of approximately 6.6 million underlying shares (given that every 1 contract represents 100 underlying shares). That number works out to 43.1% of XOM's average daily trading volume over the past month, of 15.4 million shares..