A group of around 30 global banks would face tougher capital requirements under the latest proposal on how to deal with "global systemically important financial institutions", or G-SIFIs.The proposed group now appears certain to include no Australian banks. There has been periodic concern among Australian regulators that a G-SIFI proposal could be wide enough to encompass Australia's Big Four.Bundesbank board member Andreas Dombret said on Friday that 25 to 30 G-SIFIs would "in all likelihood" be required to hold additional capital equal to two to three per cent of their assets. The Financial Times also reported at the end of last week that "about 30 of the world's biggest banks" were being targeted in the latest G-SIFI proposal.Confirmation of the size of the G-SIFI group comes ahead of important global regulatory meetings this week. The Basel Committee meets on 23 and 24 June, and the committee's oversight group - the Group of Governors and Heads of Supervision - meets the day after. The Financial Stability Board, which works on financial stability for the G20 group of major economies, meets on 18 July.The G-SIFIs are to be subjected to tougher capital requirements because it is believed their failure would be likely to inflict disproportionate long-term damage on the world's financial system.The leaked proposal takes the multi-tiered approach to G-SIFIs that regulators have increasingly favoured over recent months.At least eight banks would face the highest capital surcharge of 2.5 per cent, the Financial Times report said. It named those eight as Citigroup, JPMorgan, Bank of America, Deutsche Bank, HSBC, BNP Paribas, Royal Bank of Scotland and Barclays.A second group - including Goldman Sachs, Morgan Stanley, UBS and Credit Suisse - would face a 2.0 per cent surcharge. Other banks in the group of 30 would face surcharges of 0.5 per cent to 2.0 per cent.The surcharges would be required on top of the 7.0 per cent of assets that the Basel III framework requires banks to hold as tier-one capital.On Friday, the Financial Times reported that the list "remained fluid". The German newspaper Handelsblatt reported a senior bank official saying that "everything is in flux".The paper also said that Japanese and French negotiators were trying to keep Crédit Agricole, Société Générale, Mitsubishi UFJ, Mizuho and Sumitomo Mitsui out of the top categories.The US banks that would be affected by the decision are also lobbying for changes, arguing among other things that the rules would put Citigroup, JPMorgan and Bank of America at a disadvantage against their slightly smaller rivals.Meanwhile, European nations continue to debate the strictness of the definitions of capital and liquidity that will apply when the Basel III Framework is implemented, according to the Wall Street Journal.