Call buyers triple their money in $JD has broken out of a month-long range, handing big gains to bullish option traders.

On June 15, Investitute’s tracking systems detected the purchase of 16,000 September $40 calls for $1.38 to $1.80 with shares at $37.55. Volume was well above the strike’s open interest of 9,004 contracts, indicating that this was fresh buying.

Today those calls sold for $5.25, tripling in value. The stock rose 20.5 percent in the same time period, a significant advance but nowhere near that of its options.

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.

JD jumped 4.57 percent to $45.27 today. The Chinese e-commerce company hired a top cloud-computing executive from Microsoft yesterday and broke above its 50-day moving average.