When news leaked last week that Barclays may be on the hunt for a large US retail bank, just 18 months after swallowing Lehman Brothers' US operations, some analysts speculated that it was part of a push to rebalance the bank's earnings.

The impact of regulatory changes on Barclays Capital, the booming but volatile investment banking division that last year contributed nearly half of group pre-tax profits, is likely to force Barclays to beef up its presence in less risky businesses, in particular the amount of liquid, retail deposits it holds, they said.

A big US acquisition would also address the problem of how Barclays will derive two-thirds of its profits from outside the investment bank "over time", as it has repeatedly assured investors.