Ctrip.com International, Ltd. (ADR) (NASDAQ:CTRP - 24.51) is up about 2% today, and is attempting to topple its 80-week moving average for the first time since late July. As a result, roughly 11,000 calls have crossed the tape so far, which is 18 times the security's expected intraday call volume. By contrast, fewer than 250 puts have been exchanged.

However, not all of today's call activity is of the bullish variety. More than 6,400 contracts have traded at the March 26 strike -- the bulk of them at the bid price, suggesting they were sold. These out-of-the-money calls crossed at a volume-weighted average price (VWAP) of $1.06. Since this strike is currently home to just 92 contracts, it's very likely that new positions are being added here.

By selling these calls to open, traders are counting on CTRP to stay south of the $26 level through March expiration. Such a scenario would render the options worthless, and allow speculators to pocket the initial premium received from their call sales. This activity could also be reflective of a covered-call writing strategy, in which case the call sellers may actually be shareholders trying to generate income -- or perhaps obtain some downside protection -- on the stock.

Today's glut of short-term call activity runs counter to CTRP's recent trend. The equity's Schaeffer's put/call open interest ratio (SOIR) checks in at 1.97, with puts almost doubling calls among options scheduled to expire in the next three months. This ratio ranks in the 72nd percentile of its annual range, denoting a stronger-than-usual preference for near-term puts over calls.

Technically, the travel service provider is off to a promising start in 2013, having gained more than 8% year-to-date, while also besting the broader S&P 500 Index (SPX) by close to 27 percentage points during the past 40 sessions. Also of note, CTRP is due to report fourth-quarter earnings on Jan. 31, and has topped analysts' bottom-line estimates in the last two quarters. In other words, should the company reveal another better-than-expected quarterly profit, it could lead to a post-earnings pop -- pushing today's calls in the money, and putting the sellers at risk for assignment.