Banks in the UK need to raise billions of pounds worth of capital to cover any upcoming risk, according to the Prudential Regulation Authority.
The financial regulator said the UK's biggest banks and building societies need to put measures in place to plug the £27.1 billion ($41.8 billion) gap in their balance sheets.
Some £13.6 billion of this is attributed to the Royal Bank of Scotland (RBS) alone, while Lloyds Banking Group and Barclays contributed £8.6 billion and £3 billion respectively.
Nationwide, one of the UK's largest building societies needs to find £400,000.
Earlier in the week the Co-operative Bank, which recently pulled out of the deal to take on over 600 branches from Lloyds, revealed its plan to reduce its £1.5 billion shortfall by using a bond-to-equity scheme.
Interestingly, HSBC, Santander UK and Standard Chartered were deemed healthy by the regulator.
Santander also pulled out of its deal to take on RBS branches last year.
By Gary Cooper