Looking at options trading activity among components of the S&P 500 index, there is noteworthy activity today in DaVita Inc (Symbol: DVA), where a total volume of 3,340 contracts has been traded thus far today, a contract volume which is representative of approximately 334,000 underlying shares (given that every 1 contract represents 100 underlying shares). That number works out to 47.9% of DVA's average daily trading volume over the past month, of 697,095 shares. Especially high volume was seen for the $13 ...