Bulls see big gains in $NFLX

Option traders have racked up big profits on upside positions opened in Netflix (NFLX) earlier this week.

On Dec. 17, our Unusual Activity Service detected the purchase of 2,400 December $312.50 calls in one print for $1.50 to $3.75 with shares at $311.58. This was clearly fresh buying, as open interest in the strike was only 1,939 contracts before that session began.

Those calls have traded for as much as $25.45 today, almost 10 times their average purchase price. The stock rose 21.29% in the same time frame, underscoring how quickly options can far outperform their underlying shares.

Long calls lock in the price where investors can buy a stock, letting them position for a rally at limited cost with the potential for significant leverage. They carry less risk than owning shares because the most that can be lost is the price of the options no matter how far the stock might fall.

NFLX was last at $337.22, up 1.51% on the day. Shares of the video-streaming giant traded higher this week after reporting regional subscriber data on Monday.