Barclays reported weaker-than-expected third-quarter results Thursday, underlining the challenges for incoming chief executive Jes Staley to make the bank more profitable.

The bank, which on Wednesday confirmed that Staley will be its new CEO from December 1, said the costs of separating its retail and investment banks in Britain - so-called "ring-fencing" - will push core costs to around £14.9 billion next year, above a previous £14.5 billion target. Its previous guidance for a 12% or higher return on equity next year in its core business was revised down to 11%.