Shares in Irish orphan and ADHD drug maker Shire Plc (NASDAQ:SHPG) shot up today on the news that AbbVie (NYSE:ABBV), faced with the oncoming patent loss for Humira and looking to lower its tax rate, made public a rejected $46.5 billion bid today. This was the third bid for Shire from AbbVie, and reportedly management is considering a fourth.

So, why does AbbVie want Shire? In the video below, health care analysts Michael Douglass and David Williamson discuss the proposed deal and what Shire has to offer AbbVie.