London - Britain's financial regulator will on Thursday say capital holes at Royal Bank of Scotland, Lloyds Banking Group and Barclays account for more than 90% of a £25bn shortfall, the Financial Times said.
The shortfall was based on estimates at the end of 2012, and the Bank of England (BoE) said in March about half the total amount it identified was already covered by projected capital accumulation plans.
Analysts say no banks are expected to need to issue new equity.
The BoE had said in March Britain's top lenders needed to fill a £25bn gap in funding by the end of the year and the BoE's Prudential Regulation Authority is due to detail where the shortfalls lie among the top eight banks and mutuals early on Thursday.
RBS will be shown to account for £10bn to £12bn, Lloyds £8bn to £9bn and Barclays £3bn to £5bn, the FT said, citing people familiar with the exercise.
The PRA and the three banks declined to comment.
Last month RBS and Lloyds agreed plans to shore up their capital with the financial regulator.
HSBC, Standard Chartered and Santander UK have long been expected to receive a clean bill of health, based on their strong capital positions.
The Co-operative Bank said last week the PRA had identified a £1.5bn hole, forcing it to restructure and impose a haircut on bondholders.
Nationwide, the UK's largest building society, has a deficit of less than £1bn, the FT said.