Basel III

Under the new Basel III

Basel III

BASEL III is a new global regulatory standard on bank capital adequacy and liquidity agreed upon by the members of the Basel Committee on Banking Supervision. The third of the Basel Accords was developed in a response to the deficiencies in financial regulation revealed by the global financial...

banking agreement large internationally active banks will be required to hold a minimum of 7% of their assets in common equity.
This regulation is to be fully effective as of 1 Jan 2019.

Sources

Wall Street Journal Monday 13 Sep 2010 "Regulators Agree to Put New Restraints on Banks" p A2 continuation of front page article titled "Banks Get New Restraints" p A1