Among the underlying components of the S&P 500 index, we saw noteworthy options trading volume today in Arista Networks Inc (ANET), where a total of 2,275 contracts have traded so far, representing approximately 227,500 underlying shares. That amounts to about 64.5% of ANET's average daily trading volume over the past month of 352,925 shares. Particularly high volume was seen for the $300 strike put option expiring October 22, 2021, with 360 contracts trading so far today, representing approximately 36,000 underlying shares of ANET. Below is a chart showing ANET's trailing twelve month trading history, with the $300 strike highlighted in orange:

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

Blackrock Inc (BLK) options are showing a volume of 2,026 contracts thus far today. That number of contracts represents approximately 202,600 underlying shares, working out to a sizeable 55.6% of BLK's average daily trading volume over the past month, of 364,515 shares. Particularly high volume was seen for the $880 strike put option expiring September 24, 2021, with 122 contracts trading so far today, representing approximately 12,200 underlying shares of BLK. Below is a chart showing BLK's trailing twelve month trading history, with the $880 strike highlighted in orange:

And Danaher Corp (DHR) saw options trading volume of 10,176 contracts, representing approximately 1.0 million underlying shares or approximately 51.4% of DHR's average daily trading volume over the past month, of 2.0 million shares. Especially high volume was seen for the $300 strike put option expiring October 15, 2021, with 3,051 contracts trading so far today, representing approximately 305,100 underlying shares of DHR. Below is a chart showing DHR's trailing twelve month trading history, with the $300 strike highlighted in orange: