BlackRock was on Thursday night poised to pay more than $13bn in cash and shares to buy Barclays Global Investors in a deal that would make the US money manager the biggest in the world – with more than $3,000bn in assets under management, several people familiar with the deal said.

Under the deal, Barclays would wind up owning nearly 20 per cent of BlackRock, while Bank of America’s existing stake – acquired as part of its purchase of Merrill Lynch – would drop to just under 35 per cent from the current 49 per cent.