1030 GMT - AstraZeneca investors might question the U.K. drugmaker's confidence in its drug pipeline after reports that it has held merger talks with Bristol Myers Squibb, Bank of America analysts say. AstraZeneca declined to comment, and BMS didn't respond to a request for comment. "Mega-mergers in the industry are uncommon, and few have been perceived as successful given the frequently cited disruption to [research and development] and have usually come from a position of weakness," the analysts say in a research note. Investors in AstraZeneca could interpret a possible deal as a sign that the company lacks confidence in its own pipeline and needs to look elsewhere to bolster growth during patent expirations in the 2030s, they add. AstraZeneca shares fall 6%. BMS shares rise 6% in U.S. premarket trading.