Medivation has already made a big move, but the bulls are looking for more.
Back on May 29, OptionMonster's trade scanners detected buying in the July 50 calls for $3.50. The investor rolled a long position in those contracts yesterday, selling 2,250 contracts for $5.25 and buying an equal number of August 55 calls for $5.85.
Calls lock in the price where shares can be purchased in the drug developer, letting investors cheaply position for a move higher. Adjusting the trade cost $0.60 and gives him or her an additional month of upside exposure.
Medivation jumped 5.77 percent to $52.04 yesterday and is up 11 percent in the last week. The stock rose more than 400 percent between November 2011 and October 2012, but has been drifting mostly sideways since then. The recent activity suggests that further gains are expected soon.
Calls accounted for more than 70 percent volume, so the session's overall tone was definitely bullish. More than 8,000 contracts traded yesterday, compared with the daily average of 1,200.
—By CNBC Contributor David Russell
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David Russell is a reporter and writer for OptionMonster.Russell has no positions in MDVN.