Shire, AstraZeneca fall in London after U.S. tax move By: MarketWatch September 23, 2014 at 04:26 AM EDT Shares of Shire and AstraZeneca are falling Tuesday as a move by the U.S. spurs worries that merger prospects for each company are at risk. Read More >> Related Stocks: AbbVie Astrazeneca Plc ADR Pfizer