The bulls hope for more good news from Fortinet, which gapped higher after a strong earnings report earlier this year.
OptionMonster's tracking programs detected the purchase of 8,758 May 23 calls for $1.50 and the sale of an equal number of May 26 calls for $0.475. Volume was more than triple the previous open interest at each strike, indicating that new positions were initiated.
Owning calls locks in the level where investors can buy shares, while selling them fixes a potential exit price. Yesterday's traders will buy the network-security stock for $23 and sell it for $26 if it rallies to the higher price. It cost them $1.025 to open that $3 spread, a profit of 193 percent on a move to $26.
Fortinet stock rose 0.45 percent to $22.31 yesterday. Following the rally in late January, it consolidated and has now pulled back to the same $22 level that was resistance in December. The company hasn't yet announced the date for first-quarter earnings, but last year it occurred on April 24.
Total option volume was 21 times greater than average in the session, with calls outnumbering puts by a bullish 96-to-1 ratio.
—By CNBC Contributor David Russell
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David Russell is a reporter and writer for OptionMonster. Russell has no positions in FTNT.