$WORK calls double overnight

Bullish option traders turned quick gains in Slack Technologies (WORK) today.

Just yesterday, Market Rebellion’s tracking systems detected the purchase of 5,700 November $27 calls for $0.10 to $0.20 with shares at $21.07. Volume was above the strike’s previous open interest of 5,069 contracts, indicating that this was fresh buying.

Those calls traded for as much as $0.35 today, more than twice their average purchase price. The stock rose 7.26% at the same time, illustrating the kind of leverage that can be achieved with options.

Long calls lock in the price where a stock can be purchased, gaining with a rally and providing leverage to the underlying shares. The contracts can quickly lose value if the stock stalls or pulls back but also carry less risk than owning the shares themselves.

WORK is up 4.66% to $22.47 this afternoon. Piper Jaffray initiated the business-software company with an “overweight” rating and a $30 price target last night.