Financial writer advises caution on investing in Merck & Co., Inc. due to negative sentiment and potential price declines. Click for more on MRK Q4 earnings.

Welcome to the Merck & Company Q4 sales and earnings conference call. [Operator instructions] This call is being recorded.

Merck's stock tumbled 11.8% Tuesday, putting it on track for its biggest one-day selloff in almost 17 years, after the drug company's softer-than-expected guidance amid struggles for its HPV vaccine ...