Looking at options trading activity among components of the S&P 500 index, there is noteworthy activity today in Leidos Holdings Inc (LDOS), where a total volume of 4,647 contracts has been traded thus far today, a contract volume which is representative of approximately 464,700 underlying shares (given that every 1 contract represents 100 underlying shares). That number works out to 60.2% of LDOS's average daily trading volume over the past month, of 771,835 shares..