Looking at options trading activity among components of the S&P 500 index, there is noteworthy activity today in Facebook Inc (FB), where a total volume of 128,847 contracts has been traded thus far today, a contract volume which is representative of approximately 12.9 million underlying shares (given that every 1 contract represents 100 underlying shares). That number works out to 57.8% of FB's average daily trading volume over the past month, of 22.3 million shares..