Basel I

What Is Basel I?

Basel I is the first major international agreement on bank capital requirements. It was issued in 1988 by the Basel Committee on Banking Supervision, a group of central banks and bank regulators that meets at the Bank for International Settlements in Basel, Switzerland. Its goals were to strengthen the stability of the international banking system and to reduce competitive inequality between banks in different countries.

How It Works

Under Basel I, a bank's required capital depends on the riskiness of its assets rather than on their total size. Each asset is assigned a risk weight, ranging from 0 percent for cash and highly rated government debt to 100 percent for most ordinary corporate loans. The weighted total is the bank's risk-weighted assets.

The framework requires total capital of at least 8 percent of risk-weighted assets. At least half of that must be Tier 1 capital, the most loss-absorbing form, which mainly consists of shareholders' equity and retained earnings. The calculation can be summarized as:

Capital ratio = Qualifying capital ÷ Risk-weighted assets, with a minimum of 8%

A Simple Example

Suppose a hypothetical bank holds 100 million in ordinary corporate loans, each weighted at 100 percent, and 50 million in government bonds with a 0 percent weight. Its risk-weighted assets would be 100 million. Under the 8 percent minimum, it would need at least 8 million in qualifying capital, with at least half of that in Tier 1 form.

Limitations

Basel I was simple, and that simplicity was also its weakness. It treated most corporate loans alike regardless of borrower quality, which gave banks an incentive to hold higher-risk loans that carried the same capital charge as safer ones. It also focused mainly on credit risk and did not address other risks well. A 1996 amendment added a charge for market risk, and the framework was later replaced by Basel II in 2004 and then by Basel III.

Why It Matters to Investors

Basel I established the basic idea that still underlies bank regulation: capital should be measured against risk. Investors reading bank financial reports will still encounter capital ratios that trace back to these rules. Understanding how risk weights and minimum ratios work helps in interpreting what a reported ratio does and does not reveal about a bank's cushion against losses.