$FB calls triple overnight

Option traders are posting exponential gains today on bullish positions opened in Facebook (FB) only one session earlier.

Just yesterday, Our market scanners found that 6,750 Weekly $190 calls expiring on Sept. 13 were bought for $1.09 to $1.13 above open interest of 2,753 contracts with shares at $185.05. Co-founder Pete Najarian cited the unusual activity at that time on CNBC’s “Halftime Report.”

Those calls have already traded up to $3.40 so far today, more than 3 times their purchase prices. The stock rose 4.24% at the same time, showing 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.

FB is up 1.92% to $190.74 this morning. The social network rallied after gapping above its 100-day moving average yesterday.