Looking at options trading activity among components of the S&P 500 index, there is noteworthy activity today in Under Armour Inc (UAA), where a total volume of 39,422 contracts has been traded thus far today, a contract volume which is representative of approximately 3.9 million underlying shares (given that every 1 contract represents 100 underlying shares). That number works out to 86.7% of UAA's average daily trading volume over the past month, of 4.5 million shares..