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At the Annual Conference on the Securities Industry, American Institute of Certified
Public Accountants and the Financial Management Division of the Securities Industry
Association, New York, New York
November 20, 2002

Financial Engineering and Financial Stability
As accounting and securities industry professionals, you are well aware of the very rapid
development in recent years of new instruments and techniques for managing financial risks.
You understand that financial engineering has both created new opportunities and posed new
challenges for the securities and accounting industries. New financial instruments allow risks
to be transferred to those most willing, and presumably most able, to assume and manage
them. And new risk-measurement techniques can form the basis for more meaningful public
disclosures of firms' risk profiles. But use of the new instruments has resulted in large and
well-documented losses to some firms, while other firms have used the new instruments to
hide losses from more traditional activities.
Policymakers generally have supported the use of derivatives and other new risk-transfer
mechanisms by regulated and unregulated entities. Policymakers have tried to create
incentives for risk mitigation and have sought to address potential pitfalls through a
combination of regulatory oversight and market discipline.
However, some have raised concerns about the potential effects of the new
risk-management techniques on the stability of the financial system as a whole. In effect,
they argue that even if individual firms manage their risks prudently and effectively, the
aggregate effect of their activities may be to make the financial system less stable. As I shall
make clear, I believe the potential for the new instruments and techniques to produce
instability has been overestimated. Nonetheless, the arguments deserve careful
consideration, not only by policymakers but by financial industry professionals as well. If the
arguments were correct, the new instruments and techniques would likely provide less
protection than the firms using them assume.
Today I will review three specific topics that have been raised in the discussion of these
instruments and techniques: (1) the dynamic hedging of options, especially options to prepay
fixed-rate mortgages, (2) the so-called herding induced by common risk-management
techniques, and (3) the concentration of counterparty credit risk that can be produced by
credit derivatives. In each case I shall first evaluate the concerns and then consider how
markets would function in the absence of the new instruments and techniques.
Dynamic Hedging of Mortgages
The development of our market for home mortgages over the past two decades has
dramatically altered the role of traditional financial intermediation by depository institutions.
Let me illustrate this change. In 1980, depository institutions, primarily savings and loan
associations, held two-thirds of home mortgages in their portfolios. That proportion has

fallen to less than one-third today. Over the same period, the share of mortgages that are
securitized has risen from 10 percent to 59 percent. Of course, intermediaries still play a
vital supporting role in today's mortgage market by originating and servicing mortgages and
by holding mortgage-backed securities in their investment portfolios.
The interest rate risk inherent in home mortgages is still present in mortgage-backed
securities. The risk is simply transferred from the originator of the mortgages to an investor,
who is presumably more willing and able to manage the risk. Nevertheless, even for the most
able, managing the risk is a significant challenge.
The challenge is in managing prepayment risk. Prepayment risk arises because mortgage
borrowers have the right to prepay their mortgages at any time without penalty. The right to
prepay is an enormously popular--and therefore almost surely a permanent--element of
mortgage finance in the United States. When market rates fall, holders of fixed-rate
mortgages find their principal being repaid as borrowers refinance with a new lower-rate
mortgage. When market rates rise, prepayment rates drop dramatically.
One common strategy for hedging the interest rate risk of a mortgage-backed security is to
short other fixed-income instruments, such as ten-year Treasury notes or interest rate swaps.
But unlike most other fixed-income securities, mortgage-backed securities carry prepayment
risk, which causes a change in the level of interest rates to change the amount of Treasuries
or swaps one needs to short for an effective hedge. Specifically, when interest rates fall,
prepayments increase, and as a result, the amount of ten-year Treasuries needed for the
hedge falls. Thus, to reduce a short position in ten-year Treasuries, the hedger must buy
ten-year Treasuries when their price is rising.
This is the point where concern emerges that financial engineering may lead to higher
market volatility. Such "dynamic" hedgers of mortgage-backed-securities have adopted a
strategy that requires them to buy bonds when the price of bonds is rising. Conversely, they
must sell bonds when the price of bonds is falling. Put another way, they will always be
reinforcing the current direction of the market and never "leaning against the wind." Clearly,
if these hedging-related transactions are large relative to the underlying market, the hedging
strategy could make significant demands on market liquidity and lead to higher market
volatility.
That is the theoretical argument behind the concern that dynamic hedging of mortgages
could exacerbate volatility in fixed-income markets. To see whether this concern is just a
theoretical curiosity or is more practical, two more questions must be answered. First, are
the hedging-related transactions large relative to the underlying market? Second, could other
mechanisms for hedging prepayment risk have a smaller impact on volatility and therefore
hedge the risk more effectively?
On the first question, both research and market observation suggest that hedging-related
transactions are large enough to have an effect on the underlying fixed-income markets, but
the effect is small and dissipates relatively quickly. Research at the Federal Reserve Bank of
New York covering the years 1996 through 2000 and also the monetary policy tightening in
spring 1994 has found hedging-related effects to be present in U.S. dollar interest rate
movements. Although the effect was large enough to be detectable, it was small relative to
overall interest rate volatility and lasted no longer than six weeks.
Market participants have described the market conditions of November and December 2001
as a unique combination of circumstances that made the hedging-related effects much

stronger than usual. These circumstances included a recent history of declining mortgage
rates (which increased prepayment risk), a sharp unanticipated rise in market rates in
November and December, low market liquidity in the months right before year-end, and a
general reduction in activity after September 11. Even with these factors, market
participants estimate that the temporary hedging-related effect on the ten-year Treasury
yield was no more than 25 basis points--again, a measurable but small effect. According to
market reports, hedging-related effects on the underlying fixed-income markets appear to
have been muted so far this year, despite a record volume of mortgage refinancings thus far
in the second half of 2002 that has surpassed last year's peak.
Turning to the second question, market participants have other ways to hedge prepayment
risk besides dynamic hedging of the sort I have described. One way is through the
acquisition of interest rate options, either by buying an option, such as a so-called swaption,
or by issuing callable debt that has an option embedded in it. This allows the holder of a
mortgage to hedge prepayment risk without dynamic hedging. The fact that hedgers have
alternatives to dynamic hedging weakens the link between hedging and volatility. At the
same time, some have suggested that the hedging of prepayment risk by buying interest
options has begun to affect price dynamics in the options market. Clearly there are
complicated forces at work. How the hedging of prepayment risk affects markets for both
cash and derivative fixed-income instruments seems to be a fruitful topic for future research.
Also, we must keep in mind that market participants have an incentive to monitor and limit
the impact of dynamic hedging on the underlying market because the interaction makes the
hedging less effective. Suppose that the effect of hedging on the underlying market rises
substantially from its current low level. Dynamic hedging would become less effective and,
as a result, the risk premium associated with exposure to the interest rate risk of mortgagebacked securities would rise. The rise in the risk premium would reduce the demand for
hedging by inducing some homeowners to switch to adjustable-rate mortgages. It would also
increase the availability of alternatives to dynamic hedging--more swaption writers and
issuers of callable debt would step forward to take advantage of the higher risk premium. In
short, we can expect the market to find an efficient way to adjust to the changed
circumstances.
To evaluate the performance of the current market-based financing model for home
mortgages, including the effect of dynamic hedging, we need to compare its benefits and
costs relative to an appropriate alternative model. In light of the history of this market, the
relevant alternative would seem to be the intermediary-based financing model that
characterized the U.S. mortgage environment before 1980.
Given the experience to date, the shift from an intermediary-based model to a market-based
model over the past two decades has, on balance, benefited mortgage borrowers, who have
shown a strong preference for fixed-rate mortgages that can be prepaid at any time. The
value of fixed-rate prepayable mortgages outstanding has risen from around $1 trillion in
1980 to almost $5 trillion today.
As all of us are probably aware, the old model concentrated interest rate risk in depository
institutions, specifically in savings and loans. And when interest rates soared in the early
1980s, the savings and loan industry suffered huge losses with collateral effects on the real
economy. In comparison, the market-based model clearly seems to have spread the interest
rate risk of mortgages throughout the economy, with depository institutions still bearing
some of the risk through investments in mortgage-backed securities or callable debt.

What are the lessons for policymakers? I can suggest two. First, policymakers still need to
fulfill their traditional supervisory role. They need to ensure that regulated intermediaries
manage prepayment risk effectively and have adequate capital to absorb losses. Second, I
would note that new risk-transfer instruments, such as swaps and swaptions, are playing an
important role in transferring the interest rate risk of mortgages to a broader and more
diversified group of investors.
Herding
My second topic today is the concern that common approaches to risk management, such as
value-at-risk modeling, may be promoting herding behavior that can destabilize markets. The
idea is that market participants who use similar risk management techniques may respond to
a perceived increase in the riskiness of their positions by paring back the size of those
positions and perhaps by paring back positions in other markets as well. Such a response,
while rational from the perspective of individual market participants, may have the
collective and unintended consequence of reducing market liquidity at the time when it is
most needed.
I recognize the relevance of the questions and realize that herding might theoretically occur
in a number of markets. However, based on some observations of how models are actually
constructed and used at financial firms, I would like to outline three reasons why this
concern might be overstated.
First, the sophistication and structure of risk-management models vary widely. This point
applies with full force to value-at-risk models in use at commercial banks, an area the
Federal Reserve has some knowledge of through our supervisory oversight. Our examiners
have observed that banks implement a common objective--measuring the value-at-risk of the
bank's trading account--in highly diverse ways. Given their early stage of development and
the diversity with which they are implemented, the use of these models does not seem likely
to create herding behavior.
Second, other sources of diversity exist among financial firms, including differences in risk
appetites, customer bases, and product lines. These additional sources of variation create
considerable heterogeneity in financial firms' trading strategies, in their risk-taking, and in
how they respond to market shocks. In short, neither now nor in the future are the models
and the actual risk positions likely to be as similar as those assumed by observers concerned
about the potential negative implications of risk management.
Finally, risk models are, and should be, just one part of the formal risk-management process.
Regulators and institutions must not overestimate the role that models play, or should play, in
decisionmaking. Risk managers get useful information from risk models. But judgment,
experience, limits, and procedures for exceptions also play significant roles in risk
management. As a consequence, risk models are never likely to be the dominant driver of
the actions of financial firms and are therefore unlikely to generate significant herding
behavior.
As you are aware, models have brought a degree of both quantification and rigor to the
risk-management process that had been badly needed. Before the advent of models,
particularly value-at-risk models, bank managers could not easily compare or aggregate the
risks of the various activities of a firm. The fixed-income desk would summarize its risk in
terms of the portfolio's duration, the foreign exchange desk would use its net delta by
currency, and the equities desk would use portfolio standard deviation. Value-at-risk puts all

types of traded risks on a common footing--as an amount that can be lost with a certain
probability over a certain time horizon.
Formal risk modeling, while not perfect, is on balance an improvement over previous
practice. In my judgment, these models have made the risk-transfer process more efficient
than it otherwise would have been, which is the proper test. Formal models help firms
attempting to shed risk to identify available hedging strategies and choose the strategy that is
most appropriate, given the prevailing market conditions. Formal models help firms with
larger risk appetites evaluate their capacity to absorb and manage additional risks shifted
from others. I would argue that firms with larger risk appetites will be relatively more willing
to take on additional risk if they can better model and manage that risk.
At times of high market volatility, firms would still be able to sense that their firm's risk had
risen even without formal risk management. But they would be uncertain about exactly how
it affected them. They would be, in effect, flying by the seat of their pants. The uncertainty,
it seems clear, reduces the effectiveness of decisionmaking, reduces the ability to transfer
risk to someone willing to bear it because others, too, face the same uncertainty, and
therefore increases the potential for markets to simply freeze up.
What is the role for policymakers in overseeing the growth of formal risk-measurement
models? First, we must continue to promote the use of best-practice risk-management
modeling as one component of a good risk-management system. These models enable firms
to better quantify the risks they face. Having better information on risks can only improve a
firm's decisionmaking. Second, we should remind firms that formal risk modeling is just one
part of sound risk management. Firms do not look at the output of a model in isolation, nor
should they. For example, firms should continue to augment formal risk models with more
judgmental stress testing. Third, the imposition of rigid requirements on the risk models that
firms are allowed to use would be a mistake. It would increase the likelihood that risk
models could lead to herding. Also, firms are constantly improving their models, and
policymakers should support this process.
Credit Derivatives
My final topic today is credit derivatives. The credit derivatives market has grown rapidly
over the past few years. According to statistics from the Bank for International Settlements,
the notional value of credit derivatives outstanding rose from $108 billion in 1998 to $695
billion in 2001. According to market sources, this rapid growth continues unabated.
Banks have been an important engine behind the growth of credit derivatives. They typically
have used credit derivatives to transfer some of the credit risk they incur in making loans or
to create customized credit-risk exposures for investors. Banks pay the investors to take on
credit risk. The investors agree to compensate the bank in case of a credit loss.
Investors who sell credit protection can be motivated by a desire to earn higher returns in
exchange for taking on more credit risk or by a desire to increase the geographic, sectoral, or
other diversification of their credit portfolios by expanding the range of borrowers to which
they are exposed. Insurance companies, particularly insurance companies from continental
Europe, have been cited as large investors in this market.
In theory, the risk transfer associated with a bank's purchase of credit protection for its loan
book should be effective. Instead of suffering a loss when a borrower defaults, the bank now
suffers a loss only when both a borrower and its credit derivative counterparty default. The
risk of simultaneous default is certainly much lower than the risk of a single default.

Credit derivatives, while making markets more complete, are not a panacea and must be
used wisely. Most credit derivatives require the counterparty to make a payment to the bank
when a credit loss or default occurs. For this type of credit derivative, traditional credit risk
may reappear as counterparty credit risk, that is, the risk that the bank's counterparty will
not fulfill its agreement to compensate the bank in case of a credit loss. The price of a credit
derivative should take into consideration the credit risk posed by the seller of the protection
and the appropriate default correlation, though default correlations are difficult to estimate
precisely. But some credit derivatives, such as credit-linked notes, are prefunded--the
counterparty pays the principal up front and the repayment it receives at maturity is
contingent on a credit event not occurring. Banks selling these funded credit derivatives
have no counterparty credit risk at all.
Recognizing that they must understand the characteristics of new risk-sharing mechanisms,
several regulatory bodies have taken a close look at the credit derivatives market in recent
years. The Federal Reserve, in its role as a bank supervisor, monitors banks' participation in
the credit derivatives market. In addition, the U.K. Financial Services Authority and the
Bank of England have issued reports on credit derivatives in recent years. Thanks to these
efforts, we have a much better picture of the credit derivatives market than we did a year or
two ago.
These groups have all reported that they find no evidence that the credit derivatives market
threatens financial stability. The nonbank firms that are active in the credit derivatives
market, notably some insurance companies, do appear to understand the nature of the risk
they are taking on. Although regulatory capital arbitrage was cited as a factor spurring the
early growth of the credit derivatives market, the increasingly active portfolio management
of credit risk, by both banks and insurance companies, has driven growth of the market in
recent years.
Even at this relatively early stage in their life cycle, credit derivatives do appear to offer
benefits. The creation of a market for credit risk transfer has probably enhanced efficiency
and economic resiliency by enabling credit risk to be dispersed throughout the financial
system. Credit risk diversification using credit derivatives is thought by many to be one
factor that has helped banks to weather the recession of 2001, and its accompanying
increase in defaults, without apparent major problems. In recent financial releases, several
U.S. banks specifically noted that credit derivatives had helped them mitigate credit losses.
Of course, a general improvement in credit-risk management by banks in recent years is
another important factor. The experience with the 2001 recession was markedly different
from the preceding recession in the United States, in 1990 and 1991. In that recession, banks
took serious hits from credit losses, and the weakness in the banking sector led to
"headwinds" that restricted the availability of business credit and slowed the recovery.
The past two years have seen the largest-ever corporate bankruptcy, that of WorldCom, and
the largest-ever sovereign default, in Argentina. There have been many other high-profile
defaults, such as Global Crossing, Kmart, and Enron. By helping to spread the credit risk
associated with these large borrowers throughout the financial system, the credit derivative
market likely contributed to financial stability.
These large defaults give us some insight into one of the concerns I mentioned earlier--that
the growth of the credit derivatives market was being driven by investors who did not
understand the risks they were taking on. Because of the defaults of Enron, Argentina,

WorldCom, and others, investors in the market have made large payouts on credit
derivatives recently. If investors were underestimating the risks before, they certainly should
not do so now. On the contrary, there does not appear to have been any general retreat from
the market. The credit derivatives market has continued to grow. I can only conclude that
the majority of investors must have understood the risks and been willing and able to bear
them.
What should financial policymakers do in response to the rapid growth in the credit
derivatives market? Clearly, they must keep abreast of market developments so they can
perform their traditional supervisory role. Regulators should continue to insist that banks
manage their counterparty credit risk prudently. This prudence includes paying attention to
potential concentrations of counterparty credit risk.
However, just as important is ensuring that regulators keep enough distance from the
markets to give financial innovations such as credit derivatives a chance to succeed. The
new market for credit derivatives has grown largely outside of traditional regulatory
oversight, and as I have described, evidence to date suggests that it has made an important
contribution to financial stability in the most recent credit cycle.
Conclusion
The three topics I have addressed today--dynamic hedging of mortgages, risk measurement
systems such as value-at-risk, and credit derivatives--are examples of newer
risk-management techniques. Because these techniques are relatively new, regulators and
market participants must work to build their understanding of how they function in differing
economic environments. To date the new tools appear to demonstrate that financial
engineering can enhance economic efficiency and, at the same time, contribute to financial
stability by enabling firms to disperse risk throughout the financial system. All these new
techniques were made possible by the fact that financial firms have had the latitude to
develop them and pursue the ones that appear to be most useful. For all three techniques, the
best approach for policymakers is to monitor developments, to insist that regulated firms
practice sound risk management, to encourage transparency, and to avoid interfering with
financial innovations that have the potential to improve financial stability, whether they
occur inside or outside the realm of regulation.
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2002 Speeches

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