Looking at options trading activity among components of the S&P 500 index, there is noteworthy activity today in Charter Communications Inc (CHTR), where a total volume of 4,950 contracts has been traded thus far today, a contract volume which is representative of approximately 495,000 underlying shares (given that every 1 contract represents 100 underlying shares). That number works out to 63% of CHTR's average daily trading volume over the past month, of 785,460 shares. Especially high volume was seen for the $710 strike call option expiring December 17, 2021, with 828 contracts trading so far today, representing approximately 82,800 underlying shares of CHTR. Below is a chart showing CHTR's trailing twelve month trading history, with the $710 strike highlighted in orange:

Start slideshow:
Today's Most Active Call & Put Options of the S&P 500 »

Under Armour Inc (UAA) saw options trading volume of 30,682 contracts, representing approximately 3.1 million underlying shares or approximately 62.3% of UAA's average daily trading volume over the past month, of 4.9 million shares. Especially high volume was seen for the $25 strike call option expiring November 05, 2021, with 9,575 contracts trading so far today, representing approximately 957,500 underlying shares of UAA. Below is a chart showing UAA's trailing twelve month trading history, with the $25 strike highlighted in orange:

And O'Reilly Automotive, Inc. (ORLY) saw options trading volume of 2,570 contracts, representing approximately 257,000 underlying shares or approximately 61.9% of ORLY's average daily trading volume over the past month, of 415,065 shares. Particularly high volume was seen for the $560 strike put option expiring January 21, 2022, with 765 contracts trading so far today, representing approximately 76,500 underlying shares of ORLY. Below is a chart showing ORLY's trailing twelve month trading history, with the $560 strike highlighted in orange: