Looking at options trading activity among components of the Russell 3000 index, there is noteworthy activity today in Horizon Pharma plc (HZNP - Get Report), where a total volume of 15,150 contracts has been traded thus far today, a contract volume which is representative of approximately 1.5 million underlying shares (given that every 1 contract represents 100 underlying shares). That number works out to 42.3% of HZNP's average daily trading volume over the past month, of 3.6 million shares. Especially high volume was seen for the $14 strike put option expiring January 20, 2017, with 10,029 contracts trading so far today, representing approximately 1.0 million underlying shares of HZNP. Below is a chart showing HZNP's trailing twelve month trading history, with the $14 strike highlighted in orange:

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iStar Inc ( STAR) options are showing a volume of 3,105 contracts thus far today. That number of contracts represents approximately 310,500 underlying shares, working out to a sizeable 42.2% of STAR's average daily trading volume over the past month, of 734,920 shares. Particularly high volume was seen for the $13 strike call option expiring January 20, 2017, with 3,000 contracts trading so far today, representing approximately 300,000 underlying shares of STAR. Below is a chart showing STAR's trailing twelve month trading history, with the $13 strike highlighted in orange:

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And Equity Lifestyle Properties Inc ( ELS) saw options trading volume of 2,005 contracts, representing approximately 200,500 underlying shares or approximately 41.7% of ELS's average daily trading volume over the past month, of 481,070 shares. Particularly high volume was seen for the $60 strike put option expiring February 17, 2017, with 500 contracts trading so far today, representing approximately 50,000 underlying shares of ELS. Below is a chart showing ELS's trailing twelve month trading history, with the $60 strike highlighted in orange:

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For the various different available expirations for HZNP options, STAR options, or ELS options, visit StockOptionsChannel.com.