The Wall Street Journal reports that National Australia Bank has filed a US$230 million claim against Goldman Sachs, arguing that the US investment bank violated "industry sales practices" when it sold mortgage-backed securities that later went bad. According to the report, NAB filed the claim in December, but it has only now come to light, through a Goldman Sachs filing with the US Securities and Exchange Commission. Standard & Poor's has cut the long-term credit ratings for Barclays and Deutsche Bank from A+ to A. S&P has also cut Credit Suisse's rating, to A- from A. S&P said "industry risk for banks with large capital market operations [have] increased and is unlikely to abate in the medium term." The US Federal Reserve has approved a final set of rules that will bring the US banking system under Basel III regulation. In a statement issued on Tuesday, the Fed said banks would have to increase the quantity and quality of their capital, with a new minimum common equity tier one capital ratio of 4.5 per cent, a capital conservation buffer of 2.5 per cent and a minimum leverage ratio of four per cent. The Fed said that its focus was on large, internationally active organisations, while it would minimise the burden on less complex financial institutions.