While shares in the bank slumped almost 30% on Thursday, difficulties started in mid-September after the Bank of England announced it would not provide capital relief for mortgage lending until 2024 (at the earliest). Metro has spent years trying to gain approval from the Prudential Regulatory Authority (PRA) to use internal models for its residential mortgage business rather than the more onerous standardised models. This would allow Metro Bank (other challengers have also pursued this type of application with the PRA) to use its own history to calculate loan risk - a departure from standard capital rules. Simply put, if loans are determined as being less risky, banks are required to hold less capital under Basel III and incoming Basel IV. Metro met with rivals including HSBC, NatWest and Lloyds on Thursday to discuss buying a third of its mortgage book in efforts to bolster its balance sheet. The bank has enlisted Morgan Stanley to advise on the situation and possible capital raise, potentially drawing on the expertise of Guillaume Gabaix - a seasoned banker who held a leading role advising UBS on the acquisition of Credit Suisse. Metro’s woes aren’t the first of their kind this year, with other lenders including Credit Suisse, Silicon Valley Bank, Signature Bank and First Republic among others which have collapsed over the last 12 months.