These talks follow an initial auction for iShares, the exchange-traded funds unit of BGI, which Barclays agreed to sell to CVC Capital Partners, the private equity group, for $4.2 billion last month.

Some analysts value BGI at 12-15 times its forecast pre-tax profits of £450 million (about $690 million) next year, more than half of which is expected to come from iShares. This would value the business at $8.2-$10.3 billion.

Barclays has resisted being bailed out by the UK government and  passed a “stress test” devised by the UK regulator the Financial Services Authority in March, but may see benefits in strengthening its balance sheet further.