It's always fun watching the best of the best compete in the Winter Olympic games. But, of course, not everyone can win. Plenty of athletes experience the proverbial agony of defeat.

That's the case with investing, too. Not every stock can be a winner. Several health-care stocks proved the point this week. One of the worst performers announced disappointing clinical study results. Two others were slammed in online articles by short-sellers. 

Which health-care stocks emerged as the most horrendous of all? Find out by watching the following slideshow.

 
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.