On Thursday's edition of Market Checkup, The Motley Fool's health-care focused show for investors, Fool health-care analyst David Williamson sheds some light on what's driving the biggest movers in the health-care space today.

Shares of Ariad Pharmaceuticals (NASDAQ:ARIA) popped 8% today on word from British newspapers that Eli Lilly (NYSE:LLY), and possibly GlaxoSmithKline (NYSE:GSK), were interested in buying the biotech. To David however, the story just doesn't add up. In this segment, he looks at why the deal wouldn't make sense for Eli Lilly or Glaxo, and why he isn't putting a lot of credence behind these reports.