The IT failure that struck Royal Bank of Scotland (RBS) will cost the bank more than expected as £50m is paid to customers in compensation.
The IT problems that struck in June meant customers of the bank and subsidiary NatWest had major issues with their accounts.
The glitch in the CA7 batch process scheduler ended with 12 million customer accounts frozen.
Customers were left unable to access funds for a week or more as RBS, NatWest and the Ulster Bank manually updated all the account balances.
RBS originally said the computer problems would cost the bank £125m, but the cost has now risen to £175m.
Compensation costs RBS an extra £50m
An RBS spokesman said the £50m increase is the result of the bank having to pay more compensation to customers than originally expected.
Read more about IT problems at RBS
RBS is investing £80m to link its multiple mainframes to eliminate any possible repeat of the problem in its IT infrastructure patched together following various corporate acquisitions.
RBS will use the money on top of the hundreds of millions already spent on IT to improve the integration of mainframes.