Calls were the options of choice on Groupon, Inc. (NASDAQ:GRPN - 4.37) yesterday, as approximately 25,000 contracts crossed the tape -- easily outnumbering the roughly 11,000 puts that traded. This represented a heavier-than-usual dose of call activity for the stock, as GRPN typically sees about 22,000 calls change hands on an average day.

Traders took a particular shine to GRPN's weekly options, as 3,963 contracts were traded at the 12/14 4.50-strike call. Most of these short-term calls traded near the ask price, indicating they were likely purchased, and open interest jumped overnight by 1,639 contracts.

By buying these calls to open, the traders are looking for GRPN to rally through the end of this week. Those weekly 4.50 calls crossed at a volume-weighted average price (VWAP) of $0.20, which would place the breakeven point on a bullish trade at $4.70 (strike price plus premium paid).

The fixation on GRPN calls is nothing new, as traders have been loading up on bullishly oriented options for weeks now. The shares have bounced considerably since bottoming out at $2.60 on Nov. 12, but -- given the stock's year-to-date drop of more than 79% -- GRPN still has plenty of ground to make up. Plus, resistance at the equity's 80-day moving average has yet to give way, despite a daily breach of this level last Friday.

However, given the stock's notably poor price action -- along with its substantial short-to-float ratio of 23% -- it's entirely possible that short sellers are scooping up out-of-the-money calls to hedge against a continued rebound, rather than to bet bullishly on GRPN.