What is Bank Capital

Bank capital is the difference between a bank's assets and liabilities, and it represents the net worth of the bank or its value to investors. The asset portion of a bank's capital includes cash, government securities, and interest-earning loans (e.g., mortgages, letters of credit, and inter-bank loans); the liabilities section of a bank's capital includes loan-loss reserves and any debt it owes. A bank's capital can be thought of as the margin to which creditors are covered if the bank would liquidate its assets.


Bank capital represents the value of a bank's equity instruments that can absorb losses and have the lowest priority in payments if the bank liquidates. While bank capital can be defined as the difference between a bank's assets and liabilities, national authorities have their own definition of regulatory capital. The main banking regulatory framework consists of international standards enacted by the Basel Committee on Banking Supervision through international accords of Basel I, Basel II, and Basel III. These standards provide a definition of the regulatory bank capital that market and banking regulators closely monitor.

Book Value of Shareholders' Equity

The bank capital can be thought of as the book value of shareholders' equity on a bank's balance sheet. Because many banks revalue their financial assets more often than companies in other industries that hold fixed assets at a historical cost, shareholders' equity can serve as a reasonable proxy for the bank capital. Typical items featured in the book value of shareholders' equity include preferred equity, common stock and paid-in capital, retained earnings, and accumulated comprehensive income. The book value of shareholders' equity is also calculated as the difference between a bank's assets and liabilities.

Regulatory Bank Capital

Because banks serve an important role in the economy by collecting savings and channeling them to productive uses through loans, the banking industry and the definition of bank capital are heavily regulated. While each country can have its own requirements, the most recent international banking regulatory accord of Basel III provides a framework for defining regulatory bank capital.

According to Basel III, regulatory bank capital is divided into tiers. These are based on subordination and a bank's ability to absorb losses with a sharp distinction of capital instruments when it is still solvent versus after it goes bankrupt. Common equity tier 1 (CET1) includes the book value of common shares, paid-in capital, and retained earnings less goodwill and any other intangibles. Instruments within CET1 must have the highest subordination and no maturity.

Tier 1 capital includes CET1 plus other instruments that are subordinated to subordinated debt, have no fixed maturity and no embedded incentive for redemption, and for which a bank can cancel dividends or coupons at any time. Tier 2 capital consists of unsecured subordinated debt and its stock surplus with an original maturity of fewer than five years minus investments in non-consolidated financial institutions subsidiaries under certain circumstances. The total regulatory capital is equal to the sum of Tier 1 and Tier 2 capital.