Astrazeneca explores $400bn megadeal with US rivalAstrazeneca is plotting a merger with US rival Bristol Myers SquibbAstrazeneca is exploring a $400bn (£300bn) merger with US rival Bristol Myers Squibb, in a deal that would create one of the world’s largest pharmaceutical groups. Astrazeneca, the UK’s second most valuable listed company behind only HSBC, has a market valuation of £196bn. New York listed Bristol Myers Squibb has a market value of roughly $133bn (£98.6bn). Astrazeneca’s share price declined 7.1 per cent in early trading to 11,726p per share. The group’s share price has risen 13.4 per cent in the twelve months, while Bristol Myers Squibb has increased 43.8 per cent.