The CCyB, which was part of the original Basel III accord, is a macroprudential tool that allows the Board to dynamically adjust capital levels of large banking firms when the risks to financial stability have meaningfully changed. In 2016, the Board released a policy statement detailing the conceptual framework it would follow to set the CCyB.
The policy statement details the range of financial-system 3/5  BIS central bankers' speeches  vulnerabilities and other factors the Board may take into account as it evaluates settings for the buffer, including but not limited to, leverage in the financial sector, leverage in the nonfinancial sector, maturity and liquidity transformation in the financial sector, and asset valuation pressures.