Basel I, that is, the 1988 Basel Accord, is primarily focused on credit risk and appropriate risk-weighting of assets. Assets of banks were classified and grouped in five categories according to credit risk, carrying risk weights of 0% (for example cash, bullion, home country debt like Treasuries), 20% (securitisations such as mortgage-backed securities (MBS) with the highest AAA rating), 50% (municipal revenue bonds, residential mortgages), 100% (for example, most corporate debt), and some assets given No rating. Banks with an international presence are required to hold capital equal to 8% of their risk-weighted assets (RWA).