The potential mega-deal between big pharma giants Pfizer (NYSE: PFE) and AstraZeneca (NYSE: AZN) is officially off, but of the two companies, which is under the most pressure?

Pfizer is surrounded by questions after not being able to close its acquisition and AstraZeneca has to deliver on the claims Pfizer was undervaluing the company's drug pipeline.

In this video, Motley Fool healthcare analysts David Williamson and Michael Douglass discuss the post-mortem on the would be inversion deal along with the challenges both stocks face going forward. Which CEO is in the hot seat? Watch and find out. 

David Williamson owns shares of Pfizer. Michael Douglass has no position in any stocks mentioned. The Motley Fool has no position in any of the stocks mentioned. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.