By Pete Najarian, co-founder of OptionMonster.NEW YORK -- Groupon ( GRPN) launched its G-Pass entertainment-ticketing service Wednesday, and some option traders liked what they saw. A trader bought 4,978 July 16 calls for 70 cents and sold the same number of July 20 calls for 15 cents, according to OptionMonster's tracking systems. He or she can now own shares for $16 but is on the hook to sell them for $20. The trader paid a net 55 cents for the right to control that spread, which carries less risk than buying the stock directly, and if GRPN rallies enough the position will make more than 600%. But if the stock doesn't move, the call spread will expire worthless. The stock's direction has been mostly south since its initial public offering in November. Groupon pushed over $14 early Wednesday but then returned to its downward trajectory and finished with a 3.47% drop to $13.08, its lowest close yet. The company connects merchants to consumers by offering goods and services at a discount through coupons purchased online. Its G-Pass service is designed to allow customers to bypass box-office lines and head straight for the entrance of events such as concerts, games, and shows. Groupon's next earnings results will be released on May 14. Overall calls in the name outnumbered puts by 20,000 to 12,000, a reflection of Wednesday's bullish sentiment. Total option volume was twice its average amount. Najarian has no positions in GRPN.