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E1FFIRS 02/27/2010 1:15:59 Page 1 Credit Risk Measurement In and Out of the Financial Crisis E1FFIRS 02/27/2010 1:15:59 Page 2 Founded in 1807, John Wiley & Sons is the oldest independent publishing company in the United States. With offices in North America, Europe, Aus- tralia and Asia, Wiley is globally committed to developing and marketing print and electronic products and services for our customers’ professional and personal knowledge and understanding. The Wiley Finance series contains books written specifically for finance and investment professionals as well as sophisticated individual investors and their financial advisors. Book topics range from portfolio management to e-commerce, risk management, financial engineering, valuation and financial instrument analysis, as well as much more. For a list of available titles, please visit our Web site at www.Wiley Finance.com. E1FFIRS 02/27/2010 1:15:59 Page 3 Credit Risk Measurement In and Out of the Financial Crisis New Approaches to Value at Risk and Other Paradigms Third Edition ANTHONY SAUNDERS LINDA ALLEN John Wiley & Sons, Inc. E1FFIRS 02/27/2010 1:15:59 Page 4 Copyright # 2010 by Anthony Saunders and Linda Allen. All rights reserved. Published by John Wiley & Sons, Inc., Hoboken, New Jersey. Published simultaneously in Canada. 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 Copyright Clearance Center, Inc., 222 Rosewood Drive, Danvers, MA 01923, (978) 750-8400, fax (978) 646-8600, or on the web at www.copyright.com. 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Includes bibliographical references and index. ISBN 978-0-470-47834-9 (cloth) 1. Bank loans. 2. Bank management. 3. Credit—Management. 4. Risk management. I. Allen, Linda, 1954- II. Saunders, Anthony, 1949- Credit risk measurement. III. Title. HG1641.S33 2010 0 332.1 20684—dc22 2009044765 Printed in the United States of America 10987654321 E1FTOC 03/15/2010 16:45:21 Page 5 Contents List of Abbreviations xi Preface xv PART ONE Bubbles and Crises: The Global Financial Crisis of 2007–2009 CHAPTER 1 Setting the Stage for Financial Meltdown 3 Introduction 3 The Changing Nature of Banking 3 Reengineering Financial Institutions and Markets 17 Summary 21 Appendix 1.1: Ratings Comparisons for the Three Major Rating Agencies 23 CHAPTER 2 The Three Phases of the Credit Crisis 24 Introduction 24 Bursting of the Credit Bubble 24 Phase 1: Credit Crisis in the Mortgage Market 29 Phase 2: The Crisis Spreads—Liquidity Risk 33 Phase 3: The Lehman Failure—Underwriting and Political Intervention Risk 37 Summary 43 CHAPTER 3 The Crisis and Regulatory Failure 45 Introduction 45 Crisis Intervention 45 v E1FTOC 03/15/2010 16:45:21 Page 6 vi CONTENTS Looking Forward: Restructuring Plans 52 Summary 64 PART TWO Probability of Default Estimation CHAPTER 4 Loans as Options: The Moody’s KMV Model 67 Introduction 67 The Link between Loans and Options 67 The Moody’s KMV Model 70 Testing the Accuracy of EDFTM Scores 74 Critiques of Moody’s KMV EDFTM Scores 86 Summary 93 Appendix 4.1: Merton’s Valuation Model 93 Appendix 4.2: Moody’s KMV RiskCalcTM 95 CHAPTER 5 Reduced Form Models: Kamakura’s Risk Manager 98 Introduction 98 Deriving Risk-Neutral Probabilities of Default 99 Generalizing the Discrete Model of Risky Debt Pricing 102 The Loss Intensity Process 105 Kamakura’s Risk Information Services (KRIS) 108 Determinants of Bond Spreads 110 Summary 114 Appendix 5.1: Understanding a Basic Intensity Process 114 CHAPTER 6 Other Credit Risk Models 117 Introduction 117 Credit Scoring Systems 117 Mortality Rate Systems 121 Artificial Neural Networks 125 Comparison of Default Probability Estimation Models 127 Summary 131 E1FTOC 03/15/2010 16:45:21 Page 7 Contents vii PART THREE Estimation of Other Model Parameters CHAPTER 7 A Critical Parameter: Loss Given Default 135 Introduction 135 Academic Models of LGD 135 Disentangling LGD and PD 142 Moody’s KMV’s Approach to LGD Estimation 143 Kamakura’s Approach to LGD Estimation 146 Summary 146 CHAPTER 8 The Credit Risk of Portfolios and Correlations 148 Introduction 148 Modern Portfolio Theory (MPT): An Overview 149 Applying MPT to Nontraded Bonds and Loans 150 Estimating Correlations across Nontraded Assets 152 Moody’s KMV’s Portfolio Manager 153 Kamakura and Other Reduced Form Models 161 Summary 165 PART FOUR Putting the Parameters Together CHAPTER 9 The VAR Approach: CreditMetrics and Other Models 169 Introduction 169 The Concept of Value at Risk 170 Capital Requirements 177 Technical Issues and Problems 180 The Portfolio Approach in CreditMetrics 184 Summary 195 Appendix 9.1: Calculating the Forward Zero Curve for Loan Valuation 195 Appendix 9.2: Estimating Unexpected Losses Using Extreme Value Theory 200 E1FTOC 03/15/2010 16:45:21 Page 8 viii CONTENTS Appendix 9.3: The Simplified Two-Asset Subportfolio Solution to the N-Asset Portfolio Case 202 Appendix 9.4: CreditMetrics and Swap Credit Risk 202 CHAPTER 10 Stress Testing Credit Risk Models: Algorithmics Mark-to-Future 208 Introduction 208 Back-Testing Credit Risk Models 209 Using the Algorithmics Mark-to-Future Model 215 Stress Testing U.S. Banks in 2009 220 Summary 227 CHAPTER 11 RAROC Models 228 Introduction 228 What Is RAROC? 228 RAROC, ROA, and RORAC 229 Alternative Forms of RAROC 230 The RAROC Denominator and Correlations 235 RAROC and EVA 238 Summary 238 PART FIVE Credit Risk Transfer Mechanisms CHAPTER 12 Credit Derivatives 243 Introduction 243 Credit Default Swaps 244 Credit Securitizations 259 Financial Firms’ Use of Credit Derivatives 269 CDS Spreads and Rating Agency Rating Systems 269 Summary 271 Appendix 12.1: Pricing the CDS Spread with Counterparty Credit Risk Exposure 272 E1FTOC 03/15/2010 16:45:21 Page 9 Contents ix CHAPTER 13 Capital Regulation 274 Introduction 274 The 2006 Basel II Plan 275 Summary 296 Appendix 13.1: Loan Rating Systems 297 Notes 303 Bibliography 341 Index 365 E1FTOC 03/15/2010 16:45:21 Page 10 E1FBETW 03/17/2010 9:38:54 Page 11 List of Abbreviations ABCP asset-backed commercial paper ABS asset-backed security AE average exposure AMA advanced measurement approach ARM adjustable rate mortgage ARS adjusted relative spread ABX index of mortgage-backed security values BHC bank holding company BIS Bank for International Settlements BISTRO Broad Index Secured Trust Offering BRW benchmark risk weight BSM Black-Scholes-Merton Model CAPM capital asset pricing model CBOE Chicago Board Options Exchange CDO collateralized debt obligation CDS credit default swap CFTC Commodity Futures Trading Commission CIO collateralized insurance obligation CLN credit-linked note CLO collateralized loan obligation CMO collateralized mortgage obligation CMR cumulative mortality rate CRE commercial real estate CS credit spread CSFP Cre´dit Suisse Financial Products CVR contingent value rights CWI creditworthiness index xi E1FBETW 03/17/2010 9:38:55 Page 12 xii LIST OF ABBREVIATIONS CYC current yield curve DD distance to default DM default mode model EAD exposure at default EBITDA earnings before interest, taxes, depreciation, and amortization EC European Community ECA Export Credit Agency EDF expected default frequency EDP estimated default probability EE expected exposure EL expected losses EVA economic value added EVT extreme value theory FA foundation approach FAS Financial Accounting Standard FASB Financial Accounting Standards Board FD fair disclosure FDIC Federal Deposit Insurance Corporation FNMA Federal National Mortgage Association FHFA Federal Housing Finance Agency FIs financial