The Basel Committee on Banking Supervision has issued revised minimum capital requirements, increasing the amount of capital that banks must hold by 1 January 2019 by an average of 40%.
A previous draft of the rules would have meant a 74% increase in capital requirements, according to analysis in the Financial Times in November.
Under the new rules, the weighted average increase in minimum capital requirements would be 40%, while the median, or midpoint, of increases would be 22%, the Committee said.
The revised market risk framework is an important component of the Basel Committee's overall efforts to reform global regulatory standards in response to the global financial crisis, the Committee said.
The final standard incorporates changes made following two consultation documents published in October 2013 and December 2014 and several quantitative impact studies, the Committee said.
The reforms focus on three main areas. There will be a limit on how much capital a bank can be move between its 'trading' and 'banking' books, and any move between the two would lower the amount of capital that the bank can report, to discourage transfers, the Committee said.
Market risk will now be measured using a more detailed 'internal models' method that looks at each trading area within a bank. This is designed to protect a bank's capital against more risky trading methods, the Committee said.
Finally, the standard method used to calculate market risk has also been changed to make the identification of problems more likely, the Committee said. This method can still be used to measure risk for those banks that do not need more sophisticated market risk measures, it said.
The Basel Committee brings together regulators from around 30 countries to coordinate rules for their banks. Its members include the Bank of England, US Federal Reserve, European Central Bank and the China Banking Regulatory Commission.