AstraZeneca stock fell as investors balked at reports of merger talks with Bristol Myers Squibb about forming one of the world's biggest drugmakers

AstraZeneca & Bristol Myers Squibb in merger talks per Financial Times. AZ worth ~$265B, BMS ~$133B. Deal may involve stock & cash; talks may not lead to deal.

Bristol Myers Squibb, which has a $133 billion market capitalization, could provide AstraZeneca with a bigger foothold in the US market.