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     The Professional Risk Managers Handbook

     A Comprehensive Guide to Current Theory and Best Practices

     ___________________________________________________ 

    Edited by Carol Alexander and Elizabeth Sheedy

    Introduced by David R. Koenig

     Volume III: Risk Management Practices

     The Official Handbook for the PRM Certification

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    The PRM Handbook    Volume III

    Copyright ? 2004 The Authors and the Professional Risk Manager ! s International Association 2 

    Copyrighted Materials

    Published by PRMIA Publications, Wilmington, DE

    No part of this publication may be reproduced, stored in a retrieval system, or transmitted in any

    form or by any means, electronic, mechanical, photocopying, recording, scanning or otherwise,

    except as permitted under Section 107 or 108 of the 1976 United States Copyright Act, without

    either the prior written permission of the Publisher, or authorization through payment of the

    appropriate per-copy fee to the Publisher. Requests for permission should be addressed to

    PRMIA Publications, PMB #5527, 2711 Centerville Road, Suite 120, Wilmington, DE, 19808 or

     via email to [email protected] .

    Limit of Liability/Disclaimer of Warranty: While the publisher and author have used their best

    efforts in preparing this book, they make no representations or warranties with respect to the

    accuracy or completeness of the contents of this book and specifically disclaim any implied

     warranties of merchantability of fitness for a particular purpose. No warranty may be created or

    extended by sales representatives or written sales materials. The advice and strategies contained

    herein may not be suitable for your situation. You should consult with a professional where

    appropriate. Neither the publisher nor author shall be liable for any loss of profit or any other

    commercial damages, including but not limited to special, incidental, consequential or other

    damages.

     This book is also available in a !Sealed" digital format and may be purchased as such by members

    of the Professional Risk Managers International Association at www.PRMIA.org .

    ISBN 0-9766097-0-3 (3 Volume Set)

    ISBN 0-9766097-3-8 (Volume III)

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    The PRM Handbook    Volume III

    Copyright ? 2004 The Authors and the Professional Risk Manager ! s International Association 3

    Contents

    Introduction .................................................................................................................................................7

    Preface to Volume III: Risk Management Practices .......................................................................9

    III.0 Capital Allocation and RAPM..........................................................................................................13

    III.0.1 Introduction ..........................................................................................................................13

    III.0.2 Economic Capital .................................................................................................................17

    III.0.3 Regulatory Capital ................................................................................................................24

    III.0.4 Capital Allocation and Risk Contributions.......................................................................31

    III.0.5 RAROC and Risk-Adjusted Performance........................................................................35

    III.0.6 Summary and Conclusions..................................................................................................39

    References................................................................................................................................................40

    III.A.1 Market Risk Management........................................... ..................................................................43

    III.A.1.1 Introduction......................................................................................................................43

    III.A.1.2 Market Risk.......................................................................................................................43

    III.A.1.3 Market Risk Management Tasks....................................................................................45

    III.A.1.4 The Organisation of Market Risk Management..........................................................47

    III.A.1.5 Market Risk Management in Fund Management........................................................49

    III.A.1.6 Market Risk Management in Banking...........................................................................57

    III.A.1.7 Market Risk Management in Non-financial Firms .....................................................66

    III.A.1.8 Summary............................................................................................................................72References................................................................................................................................................73

    III.A.2 Introduction to Value at Risk Models.........................................................................................75

    III.A.2.1 Introduction......................................................................................................................75

    III.A.2.2 Definition of VaR............................................................................................................76

    III.A.2.3 Internal Models for Market Risk Capital......................................................................78

    III.A.2.4 Analytical VaR Models....................................................................................................79

    III.A.2.5 Monte Carlo Simulation VaR.........................................................................................81

    III.A.2.6 Historical Simulation VaR..............................................................................................86

    III.A.2.7 Mapping Positions to Risk Factors ...............................................................................95

    III.A.2.8 Backtesting VaR Models.............................................................................................. 109

    III.A.2.9 Why Financial Markets Are Not #Normal......................................................... ....... 111

    III.A.2.10 Summary......................................................................................................................... 112

    References ........................................... .................................................................. ................................ 113

    III.A.3: Advanced Value at Risk Models ......................................................... .................................... 115

    III.A.3.1 Introduction................................................................................................................... 115

    III.A.3.2 Standard Distributional Assumptions........................................................................ 117

    III.A.3.3 Models of Volatility Clustering................................................................................... 121

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    III.A.3.4 Volatility Clustering and VaR...................................................................................... 126

    III.A.3.5 Alternative Solutions to Non-normality.................................................................... 134

    III.A.3.6 Decomposition of VaR................................................................................................ 142

    III.A.3.7 Principal Component Analysis.................................................................................... 149

    III.A.3.8 Summary......................................................................................................................... 154

    References ........................................... .................................................................. ................................ 155

    III.A.4 Stress Testing ......................................................... ...................................................................... 157

    III.A.4.1 Introduction................................................................................................................... 157

    III.A.4.2 Historical Context......................................................................................................... 158

    III.A.4.3 Conceptual Context...................................................................................................... 163

    III.A.4.4 Stress Testing in Practice ............................................................................................. 164

    III.A.4.5 Approaches to Stress Testing: An Overview............................................................ 166

    III.A.4.6 Historical Scenarios ...................................................................................................... 168

    III.A.4.7 Hypothetical Scenarios................................................................................................. 174

    III.A.4.8 Algorithmic Approaches to Stress Testing ............................................................... 182

    III.A.4.9 Extreme-Value Theory as a Stress-Testing Method................................................ 186

    III.A.4.10 Summary and Conclusions .......................................................................................... 187

    Further Reading.................................................................................. .................................................. 187

    References ........................................... .................................................................. ................................ 188

    III.B.1 Credit Risk Management................................................. ........................................................... 193

    III.B.1.1 Introduction................................................................................................................... 193

    III.B.1.2 A Credit To-Do List..................................................................................................... 194

    III.B.1.3 Other Tasks.................................................................................................................... 207

    III.B.1.4 Conclusions.................................................................................................................... 208

    References ........................................... .................................................................. ................................ 209

    III.B.2 Foundations of Credit Risk Modelling.......................... ........................................................... 211

    III.B.2.1 Introduction................................................................................................................... 211

    III.B.2.2 What is Default Risk?................................................................................................... 211

    III.B.2.3 Exposure, Default and Recovery Processes ............................................................. 212

    III.B.2.4 The Credit Loss Distribution...................................................................................... 213

    III.B.2.5 Expected and Unexpected Loss ................................................................................. 215

    III.B.2.6 Recovery Rates .............................................................................................................. 218

    III.B.2.7 Conclusion ..................................................................................................................... 223

    References ........................................... .................................................................. ................................ 223

    III.B.3 Credit Exposure....................................... ............................................................ ........................ 225

    III.B.3.1 Introduction................................................................................................................... 225

    III.B.3.2 Pre-settlement versus Settlement Risk....................................................................... 227

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    III.B.3.3 Exposure Profiles.......................................................................................................... 228

    III.B.3.4 Mitigation of Exposures .............................................................................................. 236

    References ........................................... .................................................................. ................................ 241

    III.B.4 Default and Credit Migration ................................................... ................................................. 243

    III.B.4.1 Default Probabilities and Term Structures of Default Rates ................................. 243

    III.B.4.2 Credit Ratings ................................................................................................................ 247

    III.B.4.3 Agency Ratings. ............................................................................................................. 252

    III.B.4.4 Credit Scoring and Internal Rating Models .............................................................. 258

    III.B.4.5 Market-Implied Default Probabilities........................................................................ 262

    III.B.4.6 Credit Rating and Credit Spreads ............................................................................... 268

    III.B.4.7 Summary......................................................................................................................... 270

    References ........................................... .................................................................. ................................ 271

    III.B.5 Portfolio Models of Credit Loss .............................................. ................................................. 273

    III.B.5.1 Introduction................................................................................................................... 273

    III.B.5.2 What Actually Drives Credit Risk at the Portfolio Level?...................................... 276

    III.B.5.3 Credit Migration Framework ...................................................................................... 279

    III.B.5.4 Conditional Transition Probabilities $  CreditPortfolioView .................................. 292

    III.B.5.5 The Contingent Claim Approach to Measuring Credit Risk ................................. 294

    III.B.5.6 The KMV Approach .................................................................................................... 300

    III.B.5.7 The Actuarial Approach............................................................................................... 307

    III.B.5.8 Summary and Conclusion............................................................................................ 312

    References ........................................... .................................................................. ................................ 312

    III.B.6 Credit Risk Capital Calculation.............................................................. .................................... 315

    III.B.6.1 Introduction.................................................................................................................. 315

    III.B.6.2 Economic Credit Capital Calculation ........................................................................ 316

    III.B.6.3 Regulatory Credit Capital: Basel I ............................................................................. 320

    III.B.6.4 Regulatory Credit Capital: Basel II............................................................................. 324

    III.B.6.5 Basel II: Credit Model Estimation and Validation .................................................. 334

    III.B.6.6 Basel II: Securitisation.................................................................................................. 336

    III.B.6.7 Advanced Topics on Economic Credit Capital ....................................................... 338

    III.B.6.8 Summary and Conclusions .......................................................................................... 340

    References ........................................... .................................................................. ................................ 341

    III.C.1 The Operational Risk Management Framework............................................. ....................... 343

    III.C.1.1 Introduction................................................................................................................... 343

    III.C.1.2 Evidence of Operational Failures............................................................................... 345

    III.C.1.3 Defining Operational Risk........................................................................................... 347

    III.C.1.4 Types of Operational Risk.......................................................................................... 348

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    III.C.1.5 Aims and Scope of Operational Risk Management ................................................ 351

    III.C.1.6 Key Components of Operational Risk...................................................................... 354

    III.C.1.7 Supervisory Guidance on Operational Risk ............................................................. 357

    III.C.1.8 Identifying Operational Risk  $  the Risk Catalogue ................................................. 358

    III.C.1.9 The Operational Risk Assessment Process............................................................... 359

    III.C.1.10 The Operational Risk Control Process...................................................................... 364

    III.C.1.11 Some Final Thoughts ................................................................................................... 365

    References ........................................... .................................................................. ................................ 366

    III.C.2 Operational Risk Process Models........ ......................................................... ............................ 367

    III.C.2.1 Introduction................................................................................................................... 367

    III.C.2.2 The Overall Process ..................................................................................................... 369

    III.C.2.3 Specific Tools ................................................................................................................ 372

    III.C.2.4 Advanced Models ......................................................................................................... 374

    III.C.2.5 Key Attributes of the ORM Framework................................................................... 378

    III.C.2.6 Integrated Economic Capital Model.......................................................................... 381

    III.C.2.7 Management Actions.................................................................................................... 384

    III.C.2.8 Risk Transfer.................................................................................................................. 386

    III.C.2.9 IT Outsourcing.............................................................................................................. 388

    References ........................................... .................................................................. ................................ 393

    III.C.3 Operational Value-at-Risk................. ............................................................ ............................. 395

    III.C.3.1 The #Loss Model Approach............................................................... ......................... 395

    III.C.3.2 The Frequency Distribution........................................................................................ 401

    III.C.3.3 The Severity Distribution ............................................................................................ 404

    III.C.3.4 The Internal Measurement Approach ....................................................................... 407

    III.C.3.5 The Loss Distribution Approach............................................................................... 411

    III.C.3.6 Aggregating ORC.......................................................................................................... 413

    III.C.3.7 Concluding Remarks .................................................................................................... 415

    References ........................................... .................................................................. ................................ 416

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    The PRM Handbook    Volume III

    Copyright ? 2004 The Authors and the Professional Risk Manager ! s International Association 7 

    Introduction

    If you're reading this, you are seeking to attain a higher standard. Congratulations!

     Those who have been a part of financial risk management for the past twenty years, have seen it

    change from an on-the-fly profession, with improvisation as a rule, to one with substantially

    higher standards, many of which are now documented and expected to be followed. Its no

    longer enough to say  you know. Now, you and your team need to prove  it.

     As its title implies, this book is the  Handbook for the Professional Risk Manager. It is for those

    professionals who seek to demonstrate their skills through certification as a Professional Risk

    Manager (PRM) in the field of financial risk management. And it is for those looking simply to

    develop their skills through an excellent reference source.

     With contributions from nearly 40 leading authors, the Handbook is designed to provide you

     with the materials needed to gain the knowledge and understanding of the building blocks of

    professional financial risk management. Financial risk management is not about avoiding risk.

    Rather, it is about understanding and communicating risk, so that risk can be taken more

    confidently and in a better way. Whether your specialism is in insurance, banking, energy, asset

    management, weather, or one of myriad other industries, this Handbook is your guide.

    In this volume, the current and best practices of Market, Credit and Operational risk

    management are described. This is where we take the foundations of Volumes I and II and apply

    them to our profession in very specific ways. Here the strategic application of risk management

    to capital allocation and risk-adjusted performance measurement takes hold. After studying all of

    the materials in the PRM Handbook, you will have read the materials necessary for passage of

    Exam III of the PRM Certification program.

     Those preparing for the PRM certification will also be preparing for Exam I on Finance Theory,

    Financial Instruments and Markets, covered in Volume I of the PRM Handbook, Exam II on the

    Mathematical Foundations of Risk Measurement, covered in Volume II of the PRM Handbook

    and Exam IV - Case Studies, Standards of Best Practice Conduct and Ethics and PRMIA

    Governance. Exam IV is where we study some failed practices, standards for the performance of

    the duties of a Professional Risk Manager, and the governance structure of our association, the

    Professional Risk Managers  International Association. The materials for this exam are freely

    available on our web site (see http://www.prmia.org/pdf/Web_based_Resources.htm ) and are

    thus outside of the Handbook.

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     At the end of your progression through these materials, you will find that you have broadened

    your knowledge and skills in ways that you might not have imagined. You will have challenged

    yourself as well. And, you will be a better risk manager. It is for this reason that we have created

    the Professional Risk Managers Handbook.

    Our deepest appreciation is extended to Prof. Carol Alexander and Prof. Elizabeth Sheedy, both

    of PRMIAs Academic Advisory Council, for their editorial work on this document. The

    commitment they have shown to ensuring the highest level of quality and relevance is beyond

    description. Our thanks also go to Laura Bianco, President of PRMIA Publications, who has

    tirelessly kept the work process moving forward and who has dedicated herself to demanding the

    finest quality output. We also thank Richard Leigh, our London-based copyeditor, for his skilful

    and timely work.

    Finally, we express our thanks to the authors who have shared their insights with us. The

    demands for sharing of their expertise are frequent. Yet, they have each taken special time for

    this project and have dedicated themselves to making the Handbook and  you  a success. We are

     very proud to bring you such a fine assembly.

    Much like PRMIA, the Handbook is a place where the best ideas of the risk profession meet. We

    hope that you will take these ideas, put them into practice and certify your knowledge by attaining

    the PRM designation. Among our membership are several hundred Chief Risk Officers / Heads

    of Risk and tens of thousands of other risk professionals who will note your achievements. They

    too know the importance of setting high standards   and the trust that capital providers and

    stakeholders have put in them. Now they put their trust in you and you can prove your

    commitment and distinction to them.

     We wish you much success during your studies and for your performance in the PRM exams!

    David R. Koenig, Executive Director, Chair, Board of Directors, PRMIA

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    Preface to Volume III: Risk Management Practices

    Section III is the ultimate part of The PRM Handbook in both senses of the word. Not only is it

    the final section, but it represents the final aims and objectives of the Handbook. Sections I

    (Finance Theory, Financial Instruments and Markets) and II (Mathematical Foundations of Risk

    Measurement) laid the necessary foundations for this discussion of risk management practices  $  

    the primary concern of most readers. Here some of the foremost practitioners and academics in

    the field provide an up-to-date, rigorous and lucid statement of modern risk management.

     The practice of risk management is evolving at a rapid pace, especially with the impending arrival

    of Basel II. Aside from these regulatory pressures, shareholders and other stakeholders

    increasingly demand higher standards of risk management and disclosure of risk. In fact, it

     would not be an overstatement to say that risk consciousness is one of the defining features of

    modern business. Nowhere is this truer than in the financial services industry. Interest in risk

    management is at an unprecedented level as institutions gather data, upgrade their models and

    systems, train their staff, review their remuneration systems, adapt their business practices and

    scrutinise controls for this new era.

    Section III is itself split into three parts which address market risk, credit risk and operational risk

    in turn. These three are the main components of risk borne by any organisation, although the

    relative importance of the mix varies. For a traditional commercial bank, credit risk has always

    been the most significant. It is defined as the risk of default on debt, swap, or other counterparty

    instruments. Credit risk may also result from a change in the value of a security, contract or asset

    resulting from a change in the counterparty s creditworthiness. In contrast, market risk refers to

    changes in the values of securities, contracts or assets resulting from movements in exchange

    rates, interest rates, commodity prices, stock prices, etc. Operational risk, the risk of loss

    resulting from inadequate or failed internal processes, people and systems or from external

    events, is not, strictly speaking, a financial risk. Operational risks are, however, an inevitable

    consequence of any business undertaking. For financial institutions and fund managers, credit

    and market risks are taken intentionally with the objective of earning returns, while operational

    risks are a by-product to be controlled. While the importance of operational risk management is

    increasingly accepted, it will probably never have the same status in the finance industry as credit

    and market risk which are the chosen areas of competence.

    For non-financial firms, the priorities are reversed. The focus should be on the risks associated

     with the particular business; the production and marketing of the service or product in which

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    expertise is held. Market and credit risks are usually of secondary importance as they are a by-

    product of the main business agenda.

     The last line of defence against risk is capital, as it ensures that a firm can continue as a going

    concern even if substantial and unexpected losses are incurred. Accordingly, one of the major

    themes of Section III is how to determine the appropriate size of this capital buffer. How much

    capital is enough to withstand unusual losses in each of the three areas of risk? The measurement

    of risk has further important implications for risk management as it is increasingly incorporated

    into the performance evaluation process. Since resources are allocated and bonuses paid on the

    basis of performance measures, it is essential that they be appropriately adjusted for risk. Only

    then will appropriate incentives be created for behaviour that is beneficial for shareholders and

    other stakeholders. Chapter III.0 explores this fundamental idea at a general level, since it is

    relevant for each of the three risk areas that follow.

    Market Risk

    Chapter III.A.1 introduces the topic of market risk as it is practised by bankers, fund managers

    and corporate treasurers. It explains the four major tasks of risk management (identification,

    assessment, monitoring and control/mitigation), thus setting the scene for the quantitative

    chapters that follow. These days one of the major tasks of risk managers is to measure risk using

     value-at-risk (VaR) models. VaR models for market risk come in many varieties. The more basic

     VaR models are the topic of Chapter III.A.2, while the advanced versions are covered in III.A.3

    along with some other advanced topics such as risk decomposition. The main challenge for risk

    managers is to model the empirical characteristics observed in the market, especially volatility

    clustering. The advanced models are generally more successful in this regard, although the basic

     versions are easier to implement. Realistically, there will never be a perfect VaR model, which is

    one of the reasons why stress tests are a popular tool. They can be considered an ad hoc solution

    to the problem of model risk. Chapter III.A.4 explains the need for stress tests and how they

    might usefully be constructed.

    Credit Risk

    Chapter III.B.1 introduces the sphere of credit risk management. Some fundamental tools for

    managing credit risk are explained here, including the use of collateral, credit limits and credit

    derivatives. Subsequent chapters on credit risk focus primarily on its modelling. Foundations for

    modelling are laid in Chapter III.B.2, which explains the three basic components of a credit loss:

    the exposure, the default probability and the recovery rate. The product of these three, which

    can be defined as random processes, is the credit loss distribution. Chapter III.B.3 takes a more

    detailed look at the exposure amount. While relatively simple to define for standard loans,

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    assessment of the exposure amount can present challenges for other credit sensitive instruments

    such as derivatives, whose values are a function of market movements. Chapter III.B.4 examines

    in detail the default probability and how it can evolve over time. It also discusses the relationship

    between credit ratings and credit spreads, and credit scoring models. Chapter III.B.5 tackles one

    of the most crucial issues for credit risk modelling: how to model credit risk in a portfolio

    context and thereby estimate credit VaR. Since diversification is one of the most important tools

    for the management of credit risk, risk measures on a portfolio basis are fundamental. A number

    of tools are examined, including the credit migration approach, the contingent claim or structural

    approach, and the actuarial approach. Finally, Chapter III.B.6 extends the discussion of credit

     VaR models to examine credit risk capital. It compares both economic capital and regulatory

    capital for credit risk as defined under the new Basel Accord.

    Operational Risk

     The framework for managing operational risk is first established in Chapter III.C.1. After

    defining operational risk, it explains how it may be identified, assessed and controlled. Chapter

    III.C.2 builds on this with a discussion of operational risk process models. By better

    understanding business processes we can find the sources of risk and often take steps to re-

    engineer these processes for greater efficiency and lower risk. One of the most perplexing issues

    for risk managers is to determine appropriate capital buffers for operational risks. Operational

     VaR is the subject of Chapter III.C.3, including discussion of loss models, standard functional

    forms, both analytical and simulation methods, and the aggregation of operational risk over all

    business lines and event types.

     Elizabeth Sheedy, Member of PRMIA! s Academic Advisory Council and co-editor of The PRM Handbook.

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    III.0 Capital Allocation and RAPM

     Andrew Aziz and Dan Rosen1

    III.0.1 Introduction

     We introduce in this chapter the definitions and key concepts regarding capital, focusing on the

    important role that capital plays in financial institutions. Readers should already be familiar with

    Chapter I.A.5, which has presented the basic principles behind the capital structure of the firm.

     There it was argued that the actual  capital  $   the physical capital that a firm holds  $  should be

    distinguished from the optimal   level of capital. The optimal capital depends on many things,

    including capital targets  that are associated with a desired level of #capital adequacy  to cover the

    potential for losses made by the firm. Capital adequacy is assessed using internal models (for

    economic capital) and for banks a certain level of capital is imposed by external standards ( regulatory 

    capital). Capital adequacy is a measure of a firms ability to remain a going concern. Thus,

    targeted levels of capital are direct functions of the riskiness of the business activities or, from a

    balance sheet perspective, the riskiness of the assets.

    In this chapter you will learn:

    the role of capital in financial institutions and the different types of capital;

    the key concepts and objectives behind regulatory capital, as well as the main calculations

    principles in the Basel I Accord and the current Basel II Accord;

    the definition and mechanics of economic capital as well as the methods to calculate it;

    the use of economic capital as a management tool for risk aggregation, risk-adjusted

    performance measurement and optimal decision making through capital allocation.

     This introductory section presents the definition of capital and its role in financial institutions.

     We make the distinction between the various types of capital: book capital, economic capital and

    regulatory capital. We discuss briefly the use of economic capital as a management tool for risk

    aggregation, decision making and performance measurement.

    III.0.1.1 Role of Capital in Financial Institution

    Banks generate revenue by taking on exposure to their customers and by earning appropriate

    returns to compensate for the risk of this exposure. In general, if a bank takes on more risk, it

    can expect to earn a greater return. The trade-off, however, is that the same bank will, in general,

    increase the possibility of facing losses to the extent that it defaults on its debt obligations and is

    forced out of business. Banks that are managed well will attempt to maximise their returns only

    1 Algorithmics Inc.

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    through risk taking that is prudent and well informed. The primary role of the risk management

    function in a bank is to ensure that the total risk taken across the enterprise is no greater than the

    bank s ability to absorb worst-case losses within some specified confidence interval.

    In its pure form, capital represents the difference between the market value of a bank s assets and

    the market value of its liabilities. Because capital can be viewed as a buffer against insolvency,

    capital adequacy is a measure of a bank s ability to remain a going concern  under adverse conditions.

    In contrast to a typical corporation, the key role of capital in a financial institution such as a bank

    is not primarily one of providing a source of funding for the organisation. Banks usually have

    ready access to funding through their deposit-taking activities, which can be increased fairly

    fluidly. Instead, the primary role of capital in a bank, apart from the transfer of ownership, is to

    act as a buffer to:

    absorb large unexpected losses;

    protect depositors and other claim holders;

    provide enough confidence to external investors and rating agencies on the financial

    health and viability of the firm.

     A firms credit rating can be seen as a measure of its capital adequacy and is generally linked to a

    specific probability that the firm will enter into default over some period of time. If we make the

    assumption that liabilities are riskless, then the credit rating of a firm becomes a function of the

    overall riskiness of its assets and the amount of capital that the bank holds. Firms which hold

    more capital are able to take on riskier assets than firms of similar credit rating which hold less

    capital.

     Typically, the sources of risk within the assets of a firm are classified as follows:

    credit risk  $   losses associated with the default (or credit downgrade) of an obligor (a

    counterparty, borrower or debt issuer);

    market risk $  losses associated with changes in market values;

    operational risk  $  losses associated with operating failures.

    Capital represents an ideal metric for aggregating risks across both different asset classes and

    across different risk types.

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    III.0.1.2 Types of Capital

     We can broadly classify capital into three types:2

     Economic capital  (EC) $ an estimate of the level of capital that a firm requires to operate its

    business with a desired target solvency level. Sometimes this is also referred to as risk

    capital .3

    Regulatory capital  (RC)  $  the capital that a bank is required to hold by regulators in order

    to operate; this is an accounting measure defined by the regulatory authorities to act as a

    proxy for economic capital.

    Book capital   (BC)  $   the actual physical capital held. While in its strictest definition this

    should be simply equity capital , more generally this might also include other assets like

    liquid debt or hybrid instruments

    In practice, many firms hold book capital in excess of the required economic and even regulatory

    capital. This reflects both historical and practical business reasons (for example, given their size,

    they might be too slow to invest it effectively), as well as their more conservative view on the

    applicability of the models. The combined forces of deregulation and the increased market

     volatility in the late 1970s motivated many banks to aggressively grow market share and to

    acquire increasingly riskier assets on their balance sheets. This emphasis on growth precipitated a

    decline of capital levels throughout the 1980s that led to fears of increasing instability in the

    international banking system. These concerns motivated the push for the creation of international

    capital adequacy standards such as those ultimately established by the Basel Committee on

    Banking Supervision (BCBS). The imposition of the Basel I Accord in 1988 proved to be

    successful in its objective of increasing worldwide capital levels to desired levels by 1993 and,

    ultimately, to reduce the overall riskiness of the international banking system.

    In general, EC is meant to reflect the true #fair market  value differential between assets and

    liabilities, and thus it is limited by the ability to mark to market a balance sheet in a manner that is

    indisputable for all key constituencies  $  the financial institution, the regulators and the investors

    themselves. As such, the determination of EC has traditionally been highly institution-specific.

     The foremost objective of regulations, however, is to define an unarguable standard for capital

    comparison that creates a level playing field across all financial institutions. Thus, regulatory

    capital has traditionally been defined with respect to accounting book value measures rather than

    2 This is a general classification, and there are various alternative definitions of capital and terminology used to describethem.3 Some authors have used alternative definitions: for example, Matten (2000, pp. 222 $ 223) defines economic capital as

    risk capital plus goodwill; Perold (2001) defines risk capital in terms of insurance (explained in Section III.0.2.6).

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    to market value measures (notwithstanding the fact that, in some cases, accounting practice

    allows balance sheet items to be reported on a market value basis).

     To capture the discrepancy between fair values and market values, regulatory capital measures

    incorporate ad hoc   approaches to normalise asset book values to reflect differences in risk. As

    such, it is recognised that regulatory capital calculations tend to contain a number of

    inconsistencies, which have led regulators to set prescribed levels on a conservative basis. In

    some cases, these inconsistencies have led to the notion of regulatory arbitrage , whereby investment

    is determined not on the basis of risk  $ reward optimisation but on the basis of regulatory capital $ 

    reward optimisation.

    III.0.1.3 Capital as a Management Tool

    Capital can be used as a powerful business management tool, since it provides a consistent metric

    to determine:

    risk aggregation;

    performance measurement;

    asset and business allocation.

     The objective of risk-adjusted performance measurement (RAPM) is to define a consistent metric

    that spans all asset and risk classes, thereby providing an #apples to apples  benchmark for

    evaluating the performance of alternative business opportunities. RAPM thus becomes an ideal

    tool for capital allocation purposes. By allocating the appropriate amount of EC to each asset, net

    expected payoffs can then be expressed as returns on capital. Each asset can, therefore, be

    assessed on a consistent basis, with returns adjusted appropriately in the context of the amount

    of risk taken on. (This is further discussed in Sections III.0.4 and III.0.5).

    Risk aggregation generally refers to the development of quantitative risk measures that

    incorporate multiple sources of risk. The most common approach is to estimate the EC that is

    necessary to absorb potential losses associated with each of the risks. EC can be seen as acommon measure that can be used to summarise and compare the different risks incurred by a

    firm, across

    different businesses and activities;

    different types of risk  $  market risk, credit risk and operational risk.

     According to a recent study (BCBS, 2003b), the application of risk aggregation and EC methods

    is still in the early stages of its evolution. While some firms remain sceptical of the value of

    reducing all risks to a single number, many now believe that there is a need for a common metric

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    that allows risk  $ return comparisons to be made systematically across business activities whose

    mix of risks may be quite different (e.g., insurance versus trading). However, there remains a wide

     variation in the manner in which aggregated risk measures such as EC are used for risk

    management decision making in practice today.

    III.0.2 Economic Capital

    Economic capital acts as a buffer that provides protection against all the credit, market,

    operational and business risks faced by an institution. EC is set at a confidence level that is less

    than 100% (e.g., 99.9%), since it would be too costly to operate at the 100% level. The

    confidence interval is chosen as a trade-off between   providing high returns on capital for

    shareholders and  providing protection to the debt holders (and achieving a desired rating) as wellas confidence to other claim holders, such as depositors.

    In so far as EC reflects the amount of capital required to maintain a firms target capital rating,

    the confidence interval can be defined at a very high quantile of the loss distribution. For

    example, to achieve a target S&P credit rating of BB, the probability of default over the next year

    for the firm cannot be greater than 3.0%, so the quantile should be set at least at 97%. In

    contrast, for the same firm to achieve a target S&P credit rating of BBB, it must lower its

    probability of default to be at most 0.5%, corresponding to the 99.5% quantile of the loss

    distribution. Given the desire to achieve a BBB rating and to remain solvent 99.5% of the time, a

    firm must have enough capital to sustain a #0.5% worst-case loss over a one-year time horizon;

    that is, 99.5% of the time the future value of the non-defaulted assets must be at least equal to

    the future value of the liabilities. Example III.0.1 below gives a simple outline of how this could

    be achieved.

    III.0.2.1 Understanding Economic Capital

    Denote by At  and D t  the market values (at time t  ) of the assets and liabilities, respectively. The

    available capital C t  for the current time, t = 0 ,and at the end of one year , t = 1, can be expressedas

    C 0 = A0  $  D 0,   (III.0.1)

     C 1 = A1  $  D 1.

    If the nominal returns on the assets and liabilities are equal to r  A  and r D , respectively, then a

     worst-case loss from all sources, l  (i.e., when C 1 = 0 for a given confidence interval), would result

    in the value of assets at t = 1 just being sufficient to cover the value of debt in t  = 1. Then

    C 1 = 0 = A0 (1 + r  A )(1 l  )  D 0(1 + r D  ).

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     Thus the maximum amount of debt allowable to sustain solvency under the worst-case scenario

    cannot exceed

    D 0 = A0 (1 + r  A )(1 l  )/(1 + r D  ).  (III.0.2)

    Since EC 0 is the minimum amount of capital required to sustain such a loss, it is given by:

     EC 0 = A0 (1    [(1 + r  A )(1 l  )/(1 + r D  )]).   (III.0.3)

    Hence the minimum amount of EC a financial institution must take on in order to avoid

    insolvency increases as the level of the worse-case loss l  increases.

     The expected return on EC  over the period from t = 0 to t  = 1 is given by

    [E(  EC 1 ) /  EC 0 ]  1.

     The expected return on EC reflects the impact of leverage on risk and reward. An increase in

    expected returns (to compensate for increased risk) is reflected in the numerator, while the

    increase in risk is reflected in the denominator (the current EC).

    Equation (III.0.3) is often expressed in terms of value-at-risk notation in the following manner:

     EC 0 = A0  $  VaR/( 1+r D  ),  (III.0.4)

     where VaR  represents the  Ai  value associated with the worst-case loss, l , corresponding to the

    appropriate ( x% ) confidence interval.

    For ease of presentation, consider the case where credit risk is the sole source of business risk to

     which the firm is exposed. Returning to equation (III.0.3), under the simplifying assumption that

    the spread between the nominal return on the assets and the return on the liabilities is roughly

    equal to the expected default loss, u , then,

     EC 0  = A0 {1 $  (1 + r D  )(1 + u  )(1 $  l  )/(1 + r D  )}   (III.0.5)

    = A0 {1 $  (1 + u  )(1 $  l  )}.

    By then ignoring second-order effects, equation (III.0.5) simplifies to the following more familiar

    expression for economic capital:

    0 0 ( ) EC A l u  . (III.0.6)

     This relationship is illustrated with respect to a default loss distribution in Figure III.0.1.

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    Credit Loss Distribution

    Loss

    Probability

    0

    Expected Loss

    VaR( %)

    Volatility

    Unexpected Loss

    Figure III.0.1: Credit loss distribution: expected and unexpected losses

    Expressions (III.0.4) and (III.0.6) highlight the link between VaR measures and EC. The

    simplifying assumption leading to equation (III.0.6) and illustrated in Figure III.0.1 is the

    approach commonly taken by practitioners and generally leads to conservative estimates (for a

    detailed discussion, see Kupiec, 2002). Thus, in its most common definition, EC is defined to

    absorb only unexpected losses  (UL) up to a certain confidence level (i.e.,  A0( l    u  )). Credit reserves  are

    traditionally set aside to absorb expected losses   (EL) over the period (i.e.,  A0u  ). More precisely,

    equation (III.0.4) shows that the VaR measure appropriate for EC should in fact measure losses

    relative to the assets initial mark-to-market (MtM) value and not  relative to the EL in its end-of-period distribution. Also, the VaR measure should explicitly account for the interest payments on

    the funding debt. While the UL approximation has very little effect on market risk, where the

    horizon is short (and EL is small) it may have a higher impact in credit risk.

    Example III.0.1

    Consider a BBB-rated firm (or a firm that has targeted a BBB rating). Suppose the firm has

    liabilities consisting of D 0 = $92 million in deposits, with a cost of debt of r D  = 5%, which have

    been invested in A0 = $100 million of assets (40% at a nominal return of 6.75% and 60% at a

    nominal return of 7%.). The weighted average nominal return across the $100 million in total

    assets is r  A = 6.9%, representing a compounded spread of 1.81%. If the nominal values of the

    assets and liabilities are equal to the market values, then the current capital for this firm is

    calculated as C 0 = $8 million (the difference between the market value of the assets and the

    market value of the liabilities).

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     Assume that, in a #0.5% worse-case scenario  the firm has a potential for a loss of 15% in the

     value of total assets. Under this scenario, the firm will become insolvent as the value of the assets

     will be A1 = $100 million ? 1.069 ? 0.85 = $90.9 million, while the value of the liabilities will be

    D 1 = $92 million ? 1.05 = $96.6 million, giving a capital shortfall of $5.7 million.

    From equation (III.0.3), the minimum amount of capital the firm must hold to avoid insolvency

    in the worst-case scenario is

     EC 0 = A0 (1    [(1 + r  A )(1 l  )/(1 + r D  )])  = 100(1 $  [1.069(1 0.15)/1.05]) = 13.46.

     Therefore, for the firm to improve its capital adequacy to the desired level, it must increase its

    capital from $8 million to $13.46 million. The shareholders should be 99.5% sure that such an

    increase in capital will ensure solvency from t  = 0 to t  = 1.

    III.0.2.2 The Top-Down Approach to Calculating Economic Capital

    EC can be seen as a common measure that can be used to summarise and compare the different

    risks incurred by a firm, across different businesses and activities, and across different types of

    risk: market, credit and operational risk. At the enterprise level, EC can be estimated based on

    aggregate information of the firms performance. Such #top-down approaches generally use one

    of two types of information: earnings or stock prices.

    III.0.2.2.1 Top-Down Earnings Volatility Approach

     A top-down approach based on a firms earnings makes the simplifying assumption that the

    market value of capital is equal to the value of a perpetual stream of expected earnings. In other

     words, by assuming that all expected future earnings of the firm are equal to the next periods

    expected earnings, the value of capital can be expressed as

    C 0 = Expected earnings / k,

     where k represents the required return associated with the riskiness of the earnings. As the

    determination of EC is based on the ability to sustain a worst-case loss associated with a given

    confidence interval,

     EC 0 = EaR / k,

     where  EaR   represents the difference between expected earnings and the earnings under the

     worst-case scenario, for a given confidence interval (see Saita, 2003). Often this approach relies

    on the additional assumption that earnings are normally distributed, and thus the confidence

    interval can be determined as a multiple of the standard deviation.

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    Limitations of the earnings volatility approach include the following:

    It requires historical performance data for reliable estimates of the mean and standard

    deviation of earnings; few companies have enough data to yield reliable estimates.

    It does not link EC directly to the sources of risk.

    In general, it does not naturally allow capital to be separated out into its market, credit

    and operational risk components, nor across different business lines or activities.

    III.0.2.2.2 Top-Down Option-Theoretic Approach

     A top-down approach based on the Black  $ Scholes $ Merton (BSM) framework (see Chapter

    III.B.5) assumes that the market value of capital can be modelled as a call option on the value of

    the firms assets where the strike price is the notional value of the debt. If the value of assets at

    the end of the period ( t = 1) is greater than the value of the debt, then the value of capital is equalto the difference between the value of the assets and the debt; otherwise (in the case of

    insolvency), it is equal to zero. Using this approach assumes we have the following information

    available:

    the current market value and volatility of the company s net assets;

    the time horizon (e.g., the average duration of the firms assets);

    the risk-free interest rate (maturity corresponding to the time horizon);

    the default threshold (the asset level at which the debt holders demand repayment and

    bankruptcy can occur).

     The BSM model allows us to estimate the implied  probability of insolvency for the firm over the

    period from t = 0 to t = 1. The EC can then be determined on the basis of reapplying the BSM

    model for a level of debt that ensures, even under the worst-case scenario (at a given confidence

    interval), that the firm remains solvent.

     An advantage of this approach over the one based on EaR is the availability of stock market data.

    However, several simplifications regarding the capital structure and model assumptions must be

    made to apply this tool in practice. Similar to the EaR approach, a key limitation is that it does

    not allow the separation of capital into different risks such as market, credit and operational risks,

    nor does it suggest how to allocate it across different business lines or activities.

    III.0.2.3 The Bottom-Up Approach to Calculating Economic Capital

    In this approach, EC is estimated by modelling individual transactions and businesses and then

    aggregating the risks using advanced statistical portfolio models and stress testing. The bottom-

    up approach has now become best practice and, in contrast to the top-down approaches,

    provides greater transparency with regard to isolating credit risk, market risk and operational risk

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    capital. Furthermore, it naturally accommodates various methodologies to allocate capital to

    individual businesses, activities and transactions.

    In a bottom-up approach, the estimation of enterprise EC requires consolidation of risks at two

    levels:

    First, it computes market risk, credit risk and operational risk at the enterprise level. To

    achieve this, a firm might use an internal VaR model for market risk, a credit VaR

    methodology for credit risk and a loss-distribution approach for operational risk.

     Then, at the second level, the firm must consolidate the capital across these risks.

     To estimate total capital, it is currently common practice to add up the credit risk capital, market

    risk capital and operational risk capital. This produces a conservative capital measure (basicallyassuming that the risks are perfectly positively correlated). However, today, many firms are now

    devoting considerable effort to measuring the correlations between these risks (and hence the

    levels of diversification), as well as developing frameworks to measure these risks in a more

    integrated way.

    III.0.2.4 Stress Testing of Portfolio Losses and Economic Capital

    In addition to the statistical approaches inherent in credit portfolio models, practitioners usually

    use stress testing as an important part of their EC methodology (see Chapter III.A.4).

    Commonly, the stress-testing methodology involves the development of one or several specific

    adverse scenarios, which are judged to be extreme (falling beyond the desired confidence level).

    Current portfolio losses are then assessed against these specific scenarios. Stress scenarios may be

    based on historical experience or management judgment.

     The translation of the specific stress scenario losses, and the combination of stress testing and

    statistical measures, to develop EC measures is today more an art than a science, largely based on

    managements objectives and judgement. In essence, firms make their own decision on the

    relative weights of the statistical and stress test results in estimating the amount of EC required tosupport a portfolio. For example, an institution might assign the EC for market risk as 50% times

    the 99% VaR plus 50% the loss outcome from some stress scenarios (thus normally being higher

    than the actual 99% VaR).

    III.0.2.5 Enterprise Capital Practices    Aggregation

     A large firm, such as a bank, acquires different types of financial risk through various businesses

    and activities. Capital is indeed a powerful tool for understanding, comparing and aggregating

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    different types of risk to determine the overall health of the firm and to support better business

    decisions.

    Such an institution is likely to have separate methodologies to measure market risk, credit risk

    and operational risk. In addition, it is likely that the institution has different methodologies to

    measure the credit risk of its larger commercial loans or its retail credits. More generally, a firm

    may have any number of methodologies for various risks and segments. If each type of risk is

    modelled separately, then the amounts of EC estimated for each need to be combined to obtain

    an enterprise capital amount. In making the combination, the firm needs to incorporate, either

    implicitly or explicitly, various correlation assumptions. The methods of aggregation are as

    follows:

    Sum of stand-alone capital for each business unit and type of risk. This methodologyessentially assumes perfect correlation across business lines and risk types and does not

    allow for diversification from them.

     Ad hoc  or top-down estimates of cross-business and cross-risk correlation. In order to

    allow for some cross-business and cross-risk diversification, a firm might aggregate the

    individual stand-alone capital estimates using analytical models and simple cross-business

    (asset) correlation estimates.

     The enterprise aggregation of capital is still in its infancy and is a topic of much research today.

    III.0.2.6 Economic Capital as Insurance for the Value of the Firm

    Standard practice is to define EC as a buffer to cover unexpected losses. Thus it is defined in

    terms of the tail of the loss distribution, using measures such as VaR. Alternatively, some

    economists have used the term #risk capital  to define capital in economic terms (Merton and

    Perold, 1993; Perold, 2001): risk capital is the smallest amount that can be invested to insure the

     value of the firms net assets4 against loss in value relative to a risk-free investment.

    For example, under this definition, the risk capital of a long US Treasury bond position is the

     value of a put option with strike equal to the forward price of the bond. As pointed out by Perold(2001), in general, the put option accounts for the full distribution of losses, whereas VaR ignores

    the magnitude of outcomes conditional on being in the extreme tail of the distribution. When

    returns are normally distributed, the value of such a put option is approximately proportional to

    the standard deviation of the return on the bond, and thus is approximately proportional to VaR.

    4  #Net assets  refers to #gross assets minus customer liabilities (swaps, insurance contracts, etc.), valued as if these

    liabilities are default-free.

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    III.0.3 Regulatory Capital

     This section considers the key concepts and objectives behind regulatory capital, as well as the

    main principles used in regulatory capital calculations in the Basel I Accord and the latest

    proposals of the current Basel II Accord.

    III.0.3.1 Regulatory Capital Principles

    In this subsection, we focus mainly on the capital regulation in the banking industry. As defined

    in Section III.0.1, regulatory capital refers to the capital that an institution is required to hold by

    regulators in order to operate. It is largely an accounting measure defined by the regulatory

    authorities to act as a proxy for economic capital. Capital adequacy is generally the single most

    important financial measure used by banking supervisors when examining the financial

    soundness of an institution.

     As also mentioned in Section III.0.1, from an internal  bank perspective, capital is designed as a

    buffer to absorb large unexpected losses, protect depositors and other claim holders, and provide

    enough confidence to external investors and rating agencies on the financial health and viability

    of the firm. In contrast, from the external   perspective of the regulator, capital adequacy

    requirements fulfil two objectives:

    Reducing systemic risk: to safeguard the security of the banking system and ensure its

    ongoing viability. In a sense, national governments act as guarantors. They have an

    interest in ensuring that banks remain capable of meeting their obligations and in

    minimising potential systemic effects on the economy. Regulatory capital helps to ensure

    that banks bear their share of the burden, otherwise borne by national governments.

    Creating a level playing field:  to ensure a more even playing field for internationally active

    banks, by submitting all banks to (roughly) the same rules.

     As we review the key concepts in regulatory capital, it is important to highlight two points:

    Regulatory requirements are continuously changing, and it is vital for practitioners to be

    familiar with both the latest regulations and the specific requirements in each

    jurisdiction.

     While the general intention is to make regulatory capital more risk-sensitive and align it

    more closely to economic capital, it is important to understand the limitations of using it

    directly for managing risk, measuring performance and pricing credits.

     The overall objective should be to set up an enterprise risk management framework, which

    measures economic capital and reconciles it with regulatory capital.

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    III.0.3.2 The Basel Committee of Banking Supervision and the Basel Accord

     A key cornerstone of international banking capital regulation is the Basel Committee on Banking

    Supervision, which first introduced the framework for international capital adequacy standards.

     This framework has been adopted as the underlying structure of all bank capital adequacy

    regulations throughout the G10, as well as many other countries around the world. Today, over

    100 countries are expected to implement the latest guidelines set by the BCBS, also referred to as

    the Basel II accord).

    Summary Chronology of Banking Regulatory Capital

    1988 $  The BCBS introduces the framework for international capital adequacy standards.

    It is adopted throughout the G10, as well as in over 100 other countries (BCBS, 1988).

    Commonly referred to as the Basel I Accord  or the BIS I Accord , it was the first step inestablishing a level playing field across member countries for internationally active banks.

     The 1988 accord focused mainly on credit risk.

    1995  $   An amendment to the initial accord further allows banks to reduce #credit-

    equivalent exposures when netting agreements are in place (BCBS, 1995).

    1996  $   The 1996 amendment5  extends the capital requirements to include risk-based

    capital for the market risk in the trading book (BCBS, 1996).

    1999 $  The BCBS issues a proposal for a new capital adequacy framework to replace the

    1988 Basel I Accord. This is commonly referred to as the Basel II Accord  or BIS II Accord .

     The new accord attempts to improve the capital adequacy framework by substantially

    increasing the risk sensitivity of the minimum capital requirements, and also

    encompassing a supervisory review and market discipline principles. Under the

    proposal, banks are required specifically to allocate capital against operational risks for

    the first time.

    2000 $ 2003  $  The BCBS releases various consultation documents and conducts major

    data collection exercises called quantitative impact studies (QIS), intended to gather

    information to assess whether it has met its goals.

     April 2003  $  The BCBS releases the third consultative paper (CP3) on the new Basel

     Accord (BCBS, 2003a).

    5 Sometimes referred to as BIS 98 , after its date of implementation.

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     June 2004 $  The final version of the Basel II Accord is published (BCBS, 2004).

    2006 $ 2007 $  Currently scheduled implementation of Basel II.

     All the papers from the BCBS can be downloaded from www.bis.org .

    III.0.3.3 Basel I Regulation

     The 1988 accord focused mainly on credit risk, establishing minimum capital standards that

    linked capital requirements to the credit exposures of banks. Prior to its implementation in 1992,

    bank capital was regulated through simple, ad hoc  capital standards. While generally prescriptive,

    Basel I left various choices to be made by local regulators, thus resulting in several variations of

    the implementation across jurisdictions. The 1996 amendment further extended the capitalrequirements to include risk-based capital for the market risk in the trading book. Basel I does

    not cover capital charges for operational risk.

    III.0.3.3.1 Minimum Capital Requirements under Basel I

    Capital requirements under Basel I are the sum of:

    credit risk capital charge, which applies to all positions in the trading and banking books

    (including OTC derivatives and balance sheet commitments);

    market risk capital charge for the trading book portfolio and off-balance sheet items.

    For market risk capital, the accord allows, in addition to a standardised method, the use of

    internal VaR models covering both general market risk (or systemic risk) and specific risk.

    Specific VaR applies to both equities and bonds. For bonds it covers the risk of defaults,

    migration and changes in spreads. The reader is referred to Chapter III.A.2 for the basics of

    market risk VaR.

     The regulatory charge for banks using internal market risk models is given by

    [ ]8

     MR SR Trigger  Market Risk Capital M VaR M SpecificVaR  , (III.0.7)

     where VaR and Specific VaR denote, respectively, the 99% market VaR and specific VaR over a

    10-day horizon, and  M  MR   and M SR   are multipliers designed to adjust the capital to cover for

    modelling errors and reward the quality of the models. The first one ranges between 3 and 4, and

    the second one between 4 and 5. Finally, the Trigger  is related to quality of controls in the bank.

    Currently it is set to 8 in North America and between 8 and 25 in the UK.

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     The methodology for credit capital is simple. Minimum capital requirements are obtained by

    multiplying the sum of all the risk-weighted assets by the capital adequacy ratio of 8% (also

    referred to as the Cook ratio ):

    8%kk

    Capital RWA . (III.0.8)

     Thus the calculation of credit regulatory requirements has three steps: converting exposures to

    credit equivalent assets; computing loan equivalents for off-balance sheet and OTC portfolios;

    and applying the capital adequacy ratio. This is described in greater detail in Chapter III.B.6.

     A great strength of Basel I is the simplicity of the framework. This has allowed it to be

    implemented in countries with different banking and accounting practices. Thus, it has been quite

    successful in achieving its two general objectives (to safeguard the stability of the banking system

    and to ensure an level playing field internationally).

    Its simplicity also has been its major weakness, as the accord does not effectively align regulatory

    capital requirements closely with an institutions risk. For example, some criticisms on the credit

    risk capital include the lack of proper differentiation for credit quality and maturity, insufficient

    incentives for credit mitigations techniques, and lack of recognition of portfolio effects (these are

    discussed briefly in Chapter III.B.6).

    III.0.3.3.2 Regulatory Arbitrage under Basel I

     The lack of differentiation in the accord, together with the financial engineering advances in

    credit risk over the last decade, have lead to the development of a regulatory capital arbitrage 

    industry. This refers to the process by which regulatory capital is reduced through instruments

    such as credit derivatives or securitisation, without an equivalent reduction of the actual risk

    being taken. Through regulatory arbitrage instruments, for example, banks typically transfer low-

    risk exposures from their banking book to their trading book, or simply place them outside the

    regulated banking system.

    III.0.3.3.3 Meeting Capital Adequacy Requirements

     Available regulatory credit capital is divided into two categories:

     Tier 1 capital: essentially shareholder funds $  equity $  and retained earnings.

     Tier 2 capital: long-term subordinated debt, other qualifying hybrid instruments and

    reserves (such as loan loss reserves).

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    From a regulatory perspective, Tier 1 capital must cover at least 50% of the total capital; that is,

     Tier 2 cannot exceed Tier 1 capital. In addition, the subordinated debt included in Tier 2 cannot

    exceed 50% of the Tier 1 capital.6

    Capital adequacy is generally expressed as a ratio. For example, an 8% capital ratio means that the

    total Tier 1 and Tier 2 capital is 8% of the risk-weighted assets (RWA). A 6% Tier 1 capital ratio

    refers to Tier 1 capital being 6% of the RWA.

    III.0.3.4 Basel II Accord    Latest Proposals

     The final version of the Basel II Accord was published in June 2004 (BCBS, 2004).7  Its

    implementation will take effect between the end of 2006 and the end of 2007.

    In this subsection we present a brief summary of the basic principles of Basel II; the key

    formulae for minimum capital requirements for credit risk are given in Chapter III.B.6. For

    greater detail, the reader is referred to the BCBS papers.

    Basel II attempts to improve capital adequacy framework along two important dimensions:

    First, the development of a capital regulation that encompasses not only minimum

    capital requirements, but also supervisory review and market discipline.

    Second, a substantial increase in the risk sensitivity of the minimum capital requirements.

     The new accord intends to foster a strong emphasis on risk management and to encourage

    ongoing improvements in banks  risk assessment capabilities. This is to be accomplished by

    closely aligning banks capital requirements with prevailing modern risk management practices,

    and by ensuring that this emphasis on risk makes its way into supervisory practices and into

    market discipline through enhanced risk- and capital-related disclosures.

     The Basel II Accord consists of three pillars: minimum capital requirements , supervisory review , and

    market discipline . We briefly summarise these below and then present the key principles behind thecomputation of minimum capital requirements.

    III.0.3.4.1 Pillar 1 - Minimum Capital Requirements

    Minimum capital requirements consist of three components:

    1. definition of capital (no major changes from the 1988 accord);

    6 A Tier 3 capital was introduced with the market risk requirements. Short-term subordinated debt can be used to meetmarket risk requirements as well, but not credit risk.

    7 A small number of open issues are still to be resolved during 2004.

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    2. definition of RWA;

    3. minimum ratio of capital/RWA (remains 8%).

    Basel II proposes to modify the definition of risk-weighted assets in two areas:

    substantive changes to the treatment of credit risk relative to the Basel I Accord;

    the introduction of an explicit treatment of operational risk that will result in a measure

    of operational risk being included in the denominator of a bank s capital ratio.

    Basel II moves away from a one-size-fits-all approach to the measurement of risk, through the

    introduction of three distinct options for the calculation of credit risk and three others for

    operational risk. These approaches present increasing complexity and risk-sensitivity. Banks and

    supervisors can thus select the approaches that are most appropriate to the stage of developmentof banks operations and of the financial market infrastructure. Chapter III.B.6 briefly reviews the

    three credit risk approaches. The operational risk approaches can be found in Chapter III.C.3.

    III.0.3.4.2 Pillar 2 - Supervisory Review

     The second pillar is based on a series of guiding principles, which point to the need for banks to

    assess their capital adequacy positions relative to their overall risks, and for supervisors to review

    and take appropriate actions in response to those assessments. Banks under internal ratings-based

    credit models will be required to demonstrate that they use the outputs of those models not only

    for minimum capital requirements but also to manage their business. The inclusion of

    supervisory review provides benefits through its emphasis on strong risk assessment capabilities

    by banks and supervisors alike. Important new components of Pillar II also include the treatment

    of stress testing, concentration risk and the residual risks arising from the use of collateral,

    guarantees and credit derivatives as well as specific securitisation exposures (these are discussed

    further in Chapter III.B.6).

    III.0.3.4.3 Pillar 3 - Market Discipline

     Also referred to as  public disclosure , the third pillar aims to encourage safe and sound bankingpractices through effective market disclosures of capital levels and risk exposures. This will help

    market participants assess better a bank s ability to remain solvent.

    III.0.3.5 A Simple Derivation of Regulatory Capital

    Recognising that the simple difference between the value of assets and the value of liabilities in

    accounting value terms is not a good indicator of the true difference in market value terms has

    led regulators to make appropriate adjustments in the calculation of regulatory capital. In this

    section, we follow a similar approach to Section III.0.2.1 to understand regulatory capital.

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