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Largest option buying in equities so far

David Russell (david.russell@optionmonster.com)

Nearing the halfway mark in today's session, here are the individual equity names with the most call and put buying on optionMONSTER's ActionTracker data system.

Merck (MRK): An investor sold 10,000 December 45 calls for $0.20 and bought the January 45 calls for $0.46. Known as a calendar spread, they're looking for the stock to remain below $45 over the next four weeks. MRK rose 0.53 percent to $43.79.

Facebook (FB): Some 12,000 weekly 24 puts expiring Friday were bought for $0.20 to $0.50 as investors position for a quick drop in the social-media stock. FB rose 4.55 percent to $24.15.

Celsion (CLSN): A block of 5,000 February 10 calls was bought for $1.15, and an equal number of January 7s were sold for $1.15 as an investor rolled a long position forward by one month in hope for further upside. CLSN rose 5.42 percent to $6.42. (See related story )

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