How to Calculate the Bank Capital to Asset Ratio?

The bank capital is the sum of resources a bank can use against insolvency risks. Its assets include share capital, retained earnings, and loans issued.

The bank capital to asset ratio is an important measure to understand the financial stability of the bank. Let us discuss what is the bank capital to asset ratio, how it is calculated, and what are its important components.

Bank Capital to Asset Ratio

The bank capital to asset ratio is also called the capital adequacy ratio of capital to risk-weighted asset ratio of a bank.

The bank capital to asset ratio is the measure of total capital held by a bank against its assets. It measures the ability of a bank to protect its solvency. It denotes the ability of a bank to pay its liabilities using its capital and assets.

Since banks provide crucial economic support to an economy in any country, their financial stability is critical. Regulatory authorities and central banks set certain requirements for commercial banks to maintain their financial stability.

The capital adequacy ratio is one of such critical requirements for banks. The ratio is a useful measure not only for regulatory authorities but for the bank management as well.

A minimum capital adequacy ratio is set by central banks or regulatory authorities in every country. Generally, the higher the ratio the better it is for the bank as it measures the financial strength of the bank.

How to Calculate the Bank Capital to Asset Ratio?

Regulatory authorities divide the bank capital into different tiers. Usually, tier 1 and tier 2 capital categories are considered in important calculations.

The assets held by a bank can be found on its balance sheet. However, an important variation of the bank’s assets is to calculate the risk-weighted assets instead of using the simple total asset value. (Discussed below in detail)

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The first step is to calculate the tier 1 and tier 2 capital of the bank. Tier 1 capital includes shareholders’ equity and retained earnings. Tier 2 includes a bank’s reserves and loans issued.

The second step is to calculate the total assets or the risk-weighted asset figure of the bank. If the analysts calculate the risk-weighted assets, they must assign the risk coefficient issued by reputed rating agencies to a bank’s assets.

Finally, we can divide the total capital of a bank by its total assets or risk-weighted assets.


The formula is given below:

Capital Adequacy Ratio = Total Bank Capital / Risk-Weighted Assets

Total Bank Capital = Tier 1 Capital + Tier 2 Capital

Risk-weighted assets can be calculated by multiplying the assets in a particular category with their risk coefficient issued by a rating agency. For example, the risk coefficient for US treasury bills is 0%. Thus, if a bank has $ 10 million of US treasury securities, its risk-weighted value will also be $ 10 million.

Minimum Requirement for Bank Capital to Asset Ratio

Central banks or regulatory authorities set the minimum requirements for bank capital to asset ratios around the world. However, the Basel Committee on Bank Supervision issued sets of international banking standards. These standards are commonly known as Basel I, Basel II, and Basel III.

Under Basel III, a bank needs to maintain a banking capital to asset or capital adequacy ratio of 8%. Basel II requires a bank to maintain a minimum of 10.5% capital adequacy ratio.

Regulators may further evaluate the financial strength of a bank. For instance, since tier 1 capital is more important, the regulatory authorities may evaluate only the tier 1 to assets ratio. Under Basel III, a bank needs to maintain a minimum of 6% tier 1 to risk-weighted assets ratio.

Working Example

Let us discuss an example to understand the capital adequacy ratio.

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Suppose a bank ABC has the following information available.

Tier 1 Capital: $ 500 million

Tier 2 Capital: $ 200 million

Total Capital: $ 700 million


Debentures: $ 1,500 million

Mortgages: $ 2,000 million

Loans to Government Entities: $ 1,450 million

Reserves and Retained Earnings: $ 1,050 million

Total Assets:  $ 6,000 million

Capital to Assets Ratio = Total Capital / Total Assets

Capital to Assets Ratio = 700/6,000 = 11.66%

If we consider risk-weighted assets, then the capital adequacy ratio would be different.

The credit ratings will assign a 0% risk coefficient to retained earnings and loans to government entities. Thus, both of these line items in the asset list will carry full weightage.

We assume the risk coefficient for debentures and mortgages are 85% and 80% respectively. Then,

Risk-weighted Debentures: 1,500 × 85% = 1,275 million

Risk-weighted Mortgages: 2,000 × 80% = 1,600 million

Thus, total risk-weighted assets = 1,275 + 1,600 + 1,450 + 1,050 = 5,375

Now the risk adequacy ratio can be calculated as:

Risk Adequacy Ratio = Total Capital / Risk-Weighted Assets

Risk Adequacy Ratio = 700/5,375 = 13%

The bank maintains an adequate capital to risk-weighted average that is well above the required limit of 10% and 8% for Basel II and Basel III standards.

Understanding Bank Capital

We can define bank capital in several ways. The most common definition is the difference between a bank’s assets and liabilities is called bank capital.

On the balance sheet of a bank, we can see its assets that include commercial loans, debentures, mortgages, and fixed assets. On the liabilities side, we can see a bank’s loans, short-term obligations, and shareholders’ equity.

Banking standards define the bank capital as the bank’s ability to repay its liabilities and absorb losses. Thus, regulatory authorities consider a bank’s capital differently. It is termed as regulatory capital of a bank.

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The regulatory capital is further divided into tier 1 and tier 2 categories.

Tier 1 Capital

Tier 1 capital is the main source of capital for a bank. It includes equity share capital, retained earnings, reserves, and intangible assets that a bank can use primarily to secure itself from insolvency.

Tier 2 Capital

Tier 2 capital absorbs the losses of a bank if it goes into liquidation. It included unaudited retained earnings, unaudited reserves, and other short-term assets.

Tier 2 capital also includes subordinated debt and surplus stocks. Usually, it includes debts and other instruments with a maturity period of fewer than five years.

Risk-Weighted Assets of a Bank

A key component of the capital adequacy ratio is the calculation of risk-weighted assets of the bank.

Regulatory authorities and credit rating agencies assign different risk scores to different asset classes. Analysts then use that score to determine the risk weightage of each type of asset.

Combined these values can give us the total risk-weighted assets of a bank. The purpose of assigning the risk coefficient is to analyze the ability of each type of asset class to protect the bank against insolvency.

Analyzing the Capital to Asset Ratio

Generally, the higher the capital to asset ratio of a bank, the safer it is. As long as the capital adequacy ratio is above the Basel III standards, it can be considered good.

Analysts can dig deeper to further analyze the capital to asset ratio. One way of evaluating the ratio is to separate the tier 1 and tier 2 capital. Many analysts analyze the tier 1 to assets ratio instead of using the total assets figure.

Similarly, analysts must consider other important performance metrics such as the liquidity of a bank in conjunction with the capital adequacy ratio. It provides a complete picture of the financial stability of a bank.