Merck (NYSE:MRK), a well-known dividend stock and longtime Dow component, is of interest to many investors throughout the world. However, as with any investment, there are compelling reasons to both buy and sell this stock.

In the following video, health-care analysts Max Macaluso and David Williamson take a close look at both sides of the coin and debate the importance of Merck's losing patent protection for its leading asthma drug, Singulair.

This article represents the opinion of the writer, who may disagree with the “official” recommendation position of a Motley Fool premium advisory service. We’re motley! Questioning an investing thesis -- even one of our own -- helps us all think critically about investing and make decisions that help us become smarter, happier, and richer.