http://www.fool.com/investing/general/2015/02/16/deal-hungry-pfizer-wont-stop-with-hospira-who-coul.aspx "Recently, high profile Bernstein analyst Tim Anderson said that Pfizer execs told him the company needs an inversion deal to compete on equal footing with overseas companies, both for tax-rate purposes and for access to overseas cash. That's why analysts figure it could make a run at fellow Big Pharma GlaxoSmithKline (NYSE: GSK ) . Glaxo's size might allow Read to make the tax inversion move he intended with AstraZeneca. The two companies' businesses would also have revenue and cost synergies. A Pfizer/Glaxo merger would also create a "genuinely world class" vaccines operation, according to Berenberg's Alistair Campbell. Glaxo's slate of childhood and adult vaccines could be added to Pfizer's Prevnar franchise, and the size of the deal would cement Pfizer's spot as the top Big Pharma -- an honor it lost after its best-selling drug Lipitor went off patent."