Earnings Preview: Merck & Co., Inc., Pfizer Inc., and Bristol-Myers Squibb Co

While today is relatively light on the earnings calendar, such is not the case tomorrow. In particular, a number of large-cap drugmakers will take to the confessional, including Merck & Co., Inc. (NYSE:MRK), Pfizer Inc. (NYSE:PFE), and Bristol-Myers Squibb Co (NYSE:BMY). Below, we'll take the pre-earnings temperature of MRK, PFE, and BMY.

• MRK is up 0.3% today at $53.06, after the company's lung cancer treatment Keytruda displayed superior overall survival rates compared to chemotherapy during a mid-stage trial. Tomorrow morning, the company is set to hit the earnings stage, and based on the stock's near-term at-the-money (ATM) straddle, the options market is pricing in a 2.8% single-day move. This is slightly more than the 2.3% swing Merck & Co., Inc. shares have averaged over the past eight quarters. It appears option traders have high expectations heading into Tuesday. During the last 20 days across the International Securities Exchange (ISE), Chicago Board Options Exchange (CBOE), and NASDAQ OMX PHLX (PHLX), MRK has racked up a call/put volume ratio of 1.65 -- with long calls handily topping puts.

• PFE option speculators have also been optimistic in recent months. The stock's 50-day ISE/CBOE/PHLX call/put volume ratio of 2.51 ranks in the high 70th percentile of its annual range. Pfizer Inc. has earned this upbeat outlook, considering the shares have rallied nearly 10% year-to-date at $34.17. Turning to earnings, the blue chip has typically swung 1.5% in the immediate aftermath of its last eight reports. Per PFE's near-term ATM straddle, expectations are for a bigger 2.7% move tomorrow, after the company tells all ahead of the bell.

• BMY is up 0.3% at $65.36, bringing its 2015 lead to 10.7%, ahead of Tuesday morning's quarterly event. Currently, the options market is pricing in a 3.4% single-session post-earnings move, based on the stock's near-term ATM straddle. Such a swing would dwarf Bristol-Myers Squibb Co's average move of 1.4%, in the wake of the past eight reports. Ahead of earnings, short-term traders have been pretty put-skewed toward the security. Specifically, BMY's Schaeffer's put/call open interest ratio (SOIR) of 0.85 ranks in the 77th percentile of its annual range. By contrast, the majority of analysts have taken a more upbeat approach to the shares, with eight of 13 doling out "buy" or better endorsements.