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. Especially high volume was seen for the $20 strike call option expiring March 19, 2021, with 25,443 contracts trading so far today, representing approximately 2.5 million underlying shares of UAA. Below is a chart showing UAA's trailing twelve month trading history, with the $20 strike highlighted in orange:

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

Align Technology Inc (ALGN) options are showing a volume of 3,217 contracts thus far today. That number of contracts represents approximately 321,700 underlying shares, working out to a sizeable 79.3% of ALGN's average daily trading volume over the past month, of 405,790 shares. Particularly high volume was seen for the $580 strike call option expiring April 16, 2021, with 551 contracts trading so far today, representing approximately 55,100 underlying shares of ALGN. Below is a chart showing ALGN's trailing twelve month trading history, with the $580 strike highlighted in orange:

And McDonald's Corp (MCD) saw options trading volume of 22,460 contracts, representing approximately 2.2 million underlying shares or approximately 74.8% of MCD's average daily trading volume over the past month, of 3.0 million shares. Particularly high volume was seen for the $225 strike call option expiring February 19, 2021, with 1,992 contracts trading so far today, representing approximately 199,200 underlying shares of MCD. Below is a chart showing MCD's trailing twelve month trading history, with the $225 strike highlighted in orange: