Banks and the Importance of Equity

Principles of economics textbooks generally omit equity from the balance sheet equation, Assets=Liabilities+Equity, to focus on money creation. Given the financial crisis that became manifest in September 2008 and its continuing aftermath, this post reinserts equity or capital to focus on the risk of insolvency bankers take in lending. The example is provided by Juliusz Jabtecki and Mateusz Machaj, "The Regulated Meltdown of 2008," Critical Review, 21(2-3): 301-328, 2009. The article often refers to capital, a richer term than equity, the term used in class. When reading the quote, you can replace capital with equity with no loss of understanding. I added Figure 2 to the quote.

Figure 1

Assets		Liabilities
Cash	$10	Equity	$5
Loans	$90	Deposits	$95
Total	$100	Total	$100

Generally speaking, "capital" is the portion of a bank's assets that does not have to be ultimately repaid to creditors--such as depositors, who are, after all, merely loaning their funds to a bank. To see why capital should offer protection against unexpected losses, consider the following simple example of a bank's balance sheet (Figure 1).

The balance sheet consists of the bank's sources of funds (liabilities) and the uses to which those funds are put (assets). By definition, the two must be equal at all times We can see that our bank has collected $100 of funds: $95 in deposits from retail customers, representing liabilities; and $5 in "capital" which for the moment, we will assume is equity capital: income from issuing shares of common stock in the bank. Such income does not have to be repaid: Shareholders have no legal right to be paid dividends; and common shares have the lowest-priority claim on other assets in case of bankruptcy.

Of the $100 of liabilities (including the $5 in capital), 90 percent is then turned into credit by being loaned out, while 10 percent is held as cash in the bank's vault as cash reserves against potential withdrawals from depositors of a portion of the $95 they have lent to the bank. A bank's loans plus its cash reserves constitute its assets.

Figure 2

Assets		Liabilities
Cash	$10	Equity	$3
Loans	$88	Deposits	$95
Total	$98	Total	$98

Now imagine that some of those to whom the bank has loaned money unexpectedly default, rendering $2 of loaned assets worthless (Figure 2). The bank has to write off these losses, diminishing the total value of assets to $98. But while the value of the bank's assets has declined by $2, the amount that it owes depositors remains exactly the same ($95). Thus, for assets ($98) to continue to equal liabilities, capital must fall to $3. Suppose, by contrast, that the bank didn't initially have any capital, and that its assets ($90 in loans plus $10 in cash) were financed fully by the collection of $100 in deposits. Any unexpected (and unaccounted for) loss would then render the bank immediately insolvent, as the assets--all that the bank has--would not suffice to pay off all that it owes.

It is only due to the fact that a portion of its financing does not have to be repaid (e.g., the portion obtained from issuing stock) that the bank has the capacity to withstand unexpected losses on the investments that it makes with the funds entrusted to it. That is the primary reason that bank regulators believe it necessary to control the amount of capital that financial institutions hold. On the other hand, holding capital constrains risk-taking (and thus, potentially, profitability); that is the point of the capital regulations. To the extent that bank managers view regulatory capital as a tax imposed on them, they will tend to see capital regulations as obstacles to be gotten around.