Looking at options trading activity among components of the S&P 500 index, there is noteworthy activity today in KLA Corp (KLAC), where a total volume of 6,557 contracts has been traded thus far today, a contract volume which is representative of approximately 655,700 underlying shares (given that every 1 contract represents 100 underlying shares). That number works out to 75.5% of KLAC's average daily trading volume over the past month, of 868,565 shares..