|
Capital is one of the most
fundamental concepts in finance. It is also one of the most elusive.
Capital is the value of a firm or other investment—it is the value of assets less the
value of liabilities. As such, it represents financial resources that
are available to absorb unforeseen losses. Investors and
regulators are interested in capital because a firm without capital is
insolvent. The more capital a firm has relative to its assets, the
more confident stakeholders are that it will meet its obligations to them.
Of course, capital alone is no guarantee of solvency. A well capitalized
firm can fail due to a lack of liquidity.
We may sometimes think of capital as the liquidation value
of a firm. If all the assets and liabilities of a firm were liquidated,
how much money would be left over for
equity investors? Of course,
liquidating a firm can be a costly undertaking, so most firms are worth
more to equity investors as a going concern than they are liquidated. It
is complications like this that make capital an elusive notion. The
challenge is to measure capital in a way that is both precise and
relevant.
According to accountants, capital is
book-value
assets less book-value liabilities, perhaps with adjustments for
off-balance-sheet items. This accounting
definition is precise, but it is not always relevant. A firm's assets may
comprise un-depreciated investments in obsolete technology or "goodwill."
A firm may have suffered a large mark-to-market
loss but be gradually accruing it over a ten year period. Even ignoring
liquidation costs, such firms might have a liquidation value that is
substantially less than the accounting value of their capital.
A different
measure of capital is the
market value of the firm's equity. For a firm
with a single class of stock, this equals the number of
shares outstanding
multiplied by the current stock price. Unencumbered by accounting
formalism, market value of equity reflects the market's assessment of the
firm's value. Of course, stock prices are subject to human emotions and
crowd mentality. A firm's stock price may fluctuate widely without any
fundamental change in its business' prospects. If the stock market soars
with a speculative bubble or crashes amidst a panic, this says little
about the fundamental value of the firm.
Regulators and risk managers
think of capital as financial resources available to, in some sense,
absorb unanticipated losses. From this perspective, capital is those
sources of funding that protect parties with claims on the firm's assets
from such losses. It can be controversial deciding which items to include
in this definition. These
might include owners' equity, retained earnings and long-term subordinated debt.
Once we settle on a definition of capital, a next step is
to determine how much capital a firm should have. Traditionally, this
question was answered for financial institutions in terms of their
capital ratio, which is defined in
terms of the book value of capital and assets as
 |
[1] |
Financial institutions tend to have capital ratios in the
range of 4% to 10%, depending of course on the definition of capital being
used.
Deregulation during the 1970s and 1980s exposed financial
institutions to increased risk. In this environment, capital became
more important as a buffer against losses. The more risk a firm
took, the more capital it needed. Because assets is a poor indicator of
risk, regulators and practitioners started modifying the traditional
capital ratio or abandoning it completely.
Modifications took the form of
risk-adjusted capital
ratios:
 |
[2] |
where risk-adjusted assets are calculated by applying
risk-based weights to specific assets and summing the results. This was
the approach employed by the 1988 Basel
Accord. Somewhat crudely, it applied weights, including
0% for
G-10 government debt
20% for
G-10 bank debt
100% for
corporate debt and the debt of non-G-10 governments
In other cases, regulators and practitioners abandoned the
capital ratio concept completely and focused instead on directly
quantifying a firm's risks and specifying capital requirements in terms of
the results. During the 1980s and 1990s, this work contributed to the development
of concepts such as
value-at-risk (VaR) and
portfolio credit risk
modeling, which make it possible to assign incremental
capital charges to individual
transactions or business lines.
For example, in certain circumstances, the
Basel Accords
require a bank to calculate the 10-day 99% VaR for its
trading book. A capital charge equal to
three times this value is then applied for the trading book's
market risk.
Once they are calculated, individual capital charges are summed, perhaps
with an adjustment to reflect
hedging or diversification
effects. A firm needs to have capital in excess of its sum capital
charges. This is called a risk-based
capital requirement to distinguish it from the assets-based
requirements obtained with capital ratios
Over the years, regulators have formalized risk-based
capital requirements
in various regulations. These have defined rules for calculating a firm's capital and
suitable capital charges. The
goal is to ensure that a firm has sufficient capital to remain solvent in
the face of losses that might arise from risks taken by the firm. These analyses
are called
regulatory capital
calculations. They have been employed in both the
1996 amendment to the Basel Accord and
Basel II.
Practitioners have used risk-based capital calculations to support
performance assessment and decision making within financial firms. The
idea is to assign capital charges to individual business lines or transactions
based on their risk. Performance is assessed by
comparing the profitability of a business line or transaction to its
capital charge. Some metric of a business line's or transaction's
return
on capital can then be calculated. With this paradigm, a financial
institution will pursue those
businesses or transactions that offer the highest return on capital. In a sense, senior management becomes like
venture capitalists, deciding in what ventures to invest their limited
capital. The process is called capital
allocation.
Conceivably, firms might perform such capital
allocation based on the formulas for capital and capital charges specified
by applicable regulations. While some firms have done this, most have not.
The problem is that regulatory capital and regulatory capital charges are
designed for more modest goals than analyzing specific business lines or
transactions. They generally don't make fine distinctions between the
riskiness of similar but modestly different transactions. For example, the 1988 Basel Accord
assigned a uniform 8% capital charge for all corporate debt—so banks would
have to hold as much capital for debt issues to a AA-rated
borrower as a BB-rated borrower. For this reason, financial institutions
have developed their own proprietary formulas for capital and capital
charges. To distinguish these from regulatory capital calculations—and to
emphasize their purpose of more accurately capturing the economic impact
of specific business lines or transactions—these are referred to as
economic capital
calculations.
While economic and regulatory capital calculations are
defined differently and serve largely different purposes, the two are
philosophically similar. They have
evolved together over the years. Regulators have borrowed concepts from the
economic capital calculations performed by banks. Economic capital
calculations have similarly benefited from the innovations of regulators.
|