Topic 1 8Cross Reference to GARP AssignedReading—Mali, Chapter6 AIM18.6:Calculateexpectedloss from recovery rates*the loss given default*andtheprobability of default.. Topic 1 8 Cross Re
Trang 1KAPLAN SCHWESER
Trang 2FRM PART II BOOK 2:
MANAGEMENT
CREDIT RISK MEASUREMENTAND MANAGEMENT
IS:CreditandCounterpartyRisk
19:Default Risk:QuantitativeMethodologies
20:Credit Risks andCredit Derivatives
21:CreditDerivativesand Credit-Linked Notes
22:The StructuringProcess
23: Cash Collateralized DebtObligations
24:Spread Risk and Default Intensity Models
25:PortfolioCreditRisk
26:Structured Credit Risk
27:Securitization
28:Understanding theSecuritizationof SubprimeMortgageCredit
29: DefiningCounterparty Credit Risk
30:MitigatingCounterparty Credit Risk
31 :QuantifyingCounterpartyCredit Exposure, I
32:QuantifyingCounterpartyCreditExposure, II:TheImpactofCollateral 224
33:Pricing Counterpart}'CreditRisk, I
PAST FRM EXAM QUESTIONS
7082
91 104 120
136157167
Trang 3FRM TARTnBOOK 2: CREDTT RISK MEASUREMENT AND MANAGEMENT
©2013 Kaplan, hie., d.b.a Kaplan Schweser All rights reserved.
Printed in die United States nf America.
ISBN: 978-1-4277ÿ467-8 1 1-4277-44A7-X PPN: 3200-3240
Required Disclaimer: GARP® does not endorse, promote, review, or warrant die accuracy of the products or services offered by Kaplan Schweser of FRM information, nor does it endorse any pass rates claimed
by the provider Further,GARP® is not responsible for any fees or costs paid by die nser to Kaplan Schweser, nor isGARP®responsible for any fees or costs of any person or entity providing any services to Kaplan Schweser, FRM®, GARP®, and Global Association of Risk Professionals™ are trademarks owned by die Global Association of Risk Professionals, Inc.
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Disclaimer: The SchweserNotes should lie used in conjunction with the original readings as set forth by GARP® The information contained in these books is based on die original readings and is believed to be accurate However, dieir accuracy cannot be guaranteed nor is any warranty conveyed as to your ultimate exam success.
©2013 Kaplan,Inc.
Page2
Trang 4READING ASSIGNMENTS AND
Thefollowingmaterialis a reviewofthe Credit Risk Measurement andManagementprinciples
designedtoaddress theAIMstatements setforthby the GlobalAssociationofRiskProfessionals.
READING ASSIGNMENTS
Allan MaLz FinancialRiskManagement:Models,History;andInstitutions. Hoboken,NJ:
JohnWiley& Sons,2011
IS.“Creditand Counterparty Risk,”Chapter6
Arnaud tieServignyandOliyier Renault Measuring andManagingCreditRisk
NewYork;McGraw-Hill,2004
19."‘Default Risk:Quantitative Mediodnlogies,” Chapter 3
ReneStulz RiskManagement&Derivatives Florence,KY:ThomsonSouth-Western,
2002.
(page11)
(page32)
20.“CreditRisks andCreditDerivatives,”Chapter IS
ChristopherCulp.StructuredFinanceandInsurance:TheArtofManagingCapitaland
Risk Hoboken,NJ: JohnWiley& Sons, 2006.
21.“CreditDerivativesand Credit-LinkedNotes,*Chapter12
22.“The StructuringProcess,”Chapter 13
23 “Cash Collateralized Debt Obligations,” Chapter 17
Allan Malz FinancialRiskManagement:Models,History, andInstitutions. Hoboken,NJ:
JohnWiley &Sons,2011
24 “Spread Risk and DefaultIntensity Models,”Chapter7
25.“Portfolio Credit Risk,” Chapter8
26.“StructuredCreditRisk,”Chapter9
Christopher Culp.StructuredFinanceand Insurance: TheArtofManagingCapitaland
Risk.Hoboken,NJ: JohnWiley& Sons,2006
(page136)
(page157)
Trang 5Book 2
ReadingAssignments and AIM Statements
28.Adam Ashcroft andTilSchuermann.“UnderstandingtheSecuritizationof
SubprimeMortgageCredit.” FederalReserveBankofNew YorkStaffReports,
No.3M(March2008).
Jon Gregory CounterpartyCredit Risk: TheNewChallengeforGlobalFinancialMarkets
WestSusses, UK;JohnWiley& Sons, 2010.
29- “DefiningCounterpartyCredit Risk/Chapter2
30 “MitigatingCounterpartyCreditRisk,”Chapter3
31 “QuantifyingCounterpartyCreditExposure,I,’Chapter4
32 “QuantifyingCounterpartyCreditExposure, II:The Impact ofCollateral,”
Trang 6Boole 2
ReadingAssignments and AIM Statements
1a. Credit andCounterpartyRisk
Candidates,aftercompletingthisreading,should he ableto:
1 Descrihe securities with different typesofcreditrisks,suchas corporatedebt,
sovereigndebt, credit derivatives,and structuredproducts, (page1 1)
2. Differentiate between bookandmarketvaluesfora firm's capitalstructure,
5 Define thefollowingtermsrelated todefault andrecovery:defaultevents,
probabilityof default, credit exposure, and lossgivendefault,(page14)
6 Calculate expected loss from recoveryrates, die lossgiven default,andthe
probabilityofdefault, (page16)
7 Differentiate hetween a creditriskeventandamarket riskeventfor marketable
securities, (page 17}
8 Summarizecreditassessment techniquessuchas credit ratingsand rating
migrations, internal ratings,andriskmodels, (page17)
9 Definecounterparty risk,describeitsdifferentaspectsand explain howit is
mitigated, (page18)
10. Describe bowcounterpartyriskisdifferentfrom creditrisk* (page18)
11. Describe the Merton Model, and useit tocalculate the valueofafirm, the valuesof
afirm’s debt andequity,and default probabilities,(page21)
12. Explain the drawbacks andassesspossibleimprovements to the Merton Model, and
identifyproprietarymodelsof rating agencies thatattempt toaddress theseissues.
(page24)
13. Describecreditfactor models and evaluateanexampleofasingle-factor model
(page24)
14 DefineCreditVaR (Value-at-Risk) (page 25)
19. DefaultRisk:Quantitative Methodologies
Candidates,after completing thisreading,should be ableto:
1. Describe the Merton modelforcorporatesecuritypricing, includingits
assumptions,strengths andweaknesses:
• Illustrate andinterpretsecurity-holder payoffsbased ontheMerton model
* Using theMerton model,calculate the valueofafirm'sdebt andequity and the
volatility of firmvalue
* Describethe results and practical implications of empiricalstudies thatusethe
Mertonmodel tovaluedebt,
(page32)
2. Describe the Moody’sKMVCreditMonitorModel to estimate probabilityof
default usingequity prices,andcompare theMoodysKMV equity model with die
Merton model,(page 34)
3 Describecreditscoringmodels and the requisitequalifiesof accuracy, parsimony,
non-triviality, feasibility, transparencyand inrerpretability, (page37)
Trang 7Bank 2
ReadingAssignments and AIM Statements
4 Defineanddifferentiateamongdie followingquantitativemethodologies for creditanalysis and scoring:
* Lineardiscriminantanalysis
* Parametricdiscrimination
* Knearest neighborapproach
* Supportvectormachines(page37)
3 Defineand differentiatethefollowingdecision rules:minimum error, minimum
risk, Neyman-PfearsonandMinimal (page3£)
6. Identifythe problemsand tradeoffsbetweenclassification and prediction modelsof
performance, (page39)
7 Describeimportantfactorsin the choiceofaparticular class ofmodel, (page39)
20.CreditRisks and Credit Derivatives
Candidates,aftercompletingtills reading,shouldheableto:
1. Explain the relationship of credit spreads,time to maturity, andinterest rates.
(page50)
2. Explain die differences between valuingsenior and subordinated debt usinga
contingent claim approach, (page52)
3 Explain, fromacontingent claim perspective, the impact stochasticinterest rates
haveondie valuationof riskybonds, equity,and die riskofdefault, (page 52)
4 Assess thecredit risksofderivatives, (page61)
5 Describe die fundamental differences between CreditRisk+,CreditMetricsandKMVcredit portfolio models, (page56)
6. Define and describeacreditderivative, credit defaultswap,and totalreturnswap
(page61)
7 Defineavulnerable option, and explain how credit risk can be incorporatedin
determining theoption’svalue,(page63)
8. Explain how to accountforcreditriskexposureinvaluingaswap, (pagje 64)
21.CreditDerivativesand Credit-LinkedNotesCandidates,aftercompletingthisreading,should he ableto:
1. Describe the mechanicsofasinglenamedcredit defaultswap (CDS),and describeparticular aspectsofCDSssuchassettlement methods, payments to the protectionseller,reference name,ownership, recoveryrights, trigger events,accruedinterest andliquidity, (pagie70)
2. Describeportfoliocredit default swaps,includingbasketCDS,Ndi toDefault
CDS, SeniorandSubordinatedBasketCDS (page72)
3 Describe the composition and useofiTraxx CDS indices, (page 74)
4 Explain the mechanicsofassetdefaultswaps, equitydefaultswaps, totalreturn
swapsand creditlinkednotes,(page75)
22.TheStructuring ProcessCandidates,aftercompletingdiisreading,shouldhe ableto:
1. Describe theobjectivesofstructuredfinance and explain the motivations forasset
securitization, (page 82)
2. Describe die process and benefits ofring-fencingassets, (pageS3)
3 Describe the roleofstructuredfinancein venturecapitalformation,risktransfer,agencycost reduction, and satisfactionofspecificinvestor demands,(page84)
Trang 8Book 2
ReadingAssignments and AIM Statements
4 Explain diesteps involvedand die various playersinastructuringprocess
(page85)
5 Define and describe theprocessof Lranchingandsubordination, and describe die
roleof loss distributions and credit racings, (page86)
23.Gish Collateralized Debt Obligations
Candidates,afcercompletingthisreading,should be ableto;
1. Definecollateralizeddebt obligations(CDOs) anddescribediemotivationsof
CDObuyersandsellers, (page91)
2. Describe the typesof collateral used in CDOs.(page91)
3 Defineandexplain diestructureof balance sheetCDOsand arbitrageCDOs
(page93)
4 Describe die benefitsofandmotivationsfor balance sheetCDOsand arbitrage
CDOs.(page94)
5 Describecashflowvs. market valueCDOs.(page94)
6 Describestatic vs. managed portfolios ofCDOs*(page95)
24.SpreadRisk and DefaultIntensityModels
Candidates,aftercompletingdiisreading,shouldbeableto;
I. Define thedifferentwaysof represendng spreads Compareanddifferentiate
between thedifferent spread conventions andcompute onespread givenodiers
when possible,(page 104)
2. Defineandcomputethe Spread‘01. (page105)
3 Explain howdefault riskforasinglecompanycan bemodeledas aBernoulli trial
(page106)
4. Explain die relationshipbetweenexponentialand Poisson distributions, (page107)
5 Define the hazard rateanduse it todefineprobabilityfunctionsfordefault time
and conditional default probabilities,(page 107)
6. Calculaterisk-neutral default racesfromspreads,(page109)
7 Describe advantages of using theCDSmarket to estimatehazard rates,(page110)
8. Explain howa CDSspread canbe used toderiveahazard rate curve,(page111)
9 Constructa hazard ratecurvehima CDSspreadcurve, (page 112)
10 Constructadefault distributioncurvefromahazard rate curve,(page1 12)
11. Explain how thedefault distributionisaffectedbytheslopingof thespreadcurve.
(page113)
12. Definespreadriskandits measurementusingthe mark-to-market andspread
volatility,(page114)
25 Portfolio Credit Risk
Candidates,aftercompletingdiis reading,shouldbe ableto;
1. Define default correlationfor credit portfolios,(page120)
2 Identify drawbacksin usingthe correlation-based credit portfolio framework
(page121)
3 Assesstheeffects of correlation on acredit portfolioanditsCreditVaR (page122)
4 Describe howasinglefactor model can beused to measureconditional default
probabilities giveneconomic health, (page124)
5 Compute thevarianceof the conditional defaultdistribution and die conditional
probability ofdefault usingasingle-factormodel,(page125)
6. Explain therelationshipbetween thedefaultcorrelationamongfirmsandtheir
single-factormodel beta parameters.Apply this relationship to compute one
parameterfrom theother,(page 126)
Trang 9Book 2
Reading Assignments and AIM Statements
7 Explain how Credit VaR ofa portfolioiscalculated using thesingle-factormodel,
andhow correlationaffects thedistribution oflossseverityfor intermediate values
between0and 1.{page 127)
8. Describe howCreditVaRcanhe calculated usingasimulationof joint defaultswith
acopula, (page129}
26.Structured Credit Risk:
Candidates,aftercompletingdiisreading,should beableto:
1. Identifycommon typesofstruerured products and the various dimensions thatare
importantto their valueandstructure, (page136)
2. Describe the roleofcapitalstructureand creditlosses in a securitization,(page137)
3 Evaluateawaterfall example ina securitization with multiple tranches, (page 138)
4 Identifythekeyparticipantsin a securitization,anddescribesome conflicts of
interest thatcan arisein theprocess, (page141)
5 Evaluateone or two iterationsofinterim cashflowsin a threetieredsecuritization
structure includingthe final cashflows toeach trancheholder, (page 142)
6 Describeasimulation approach tocalculatingcreditlossesfor different tranchesin
a securitizationofaportfolioofloans,(page145)
7 Explain how the probability of default anddefaultcorrelationamongthe
underlyingassetsofa securitizationaffects thevalue,losses and CreditVaRof
equity, junior,andsenior tranches, (page 146)
8. Defineanddescribe how defaultsensitivitiesfor tranchesare measured,(page148)
9 Summarize someof thedifferent typesof risks thatplayaroleinstructured
products, (page148)
10. Defineimpliedcorrelation and describe howit can hemeasured, (page 149)
11. Identifydie motivations for usingstructured creditproducts, (page149)
27.SecuritizationCandidates,aftercompleting thisreading,should he ableto:
1. Define securitizationanddescribe the processand therole theparticipants play.
(page157)
2. Analyze die differences in the mechanicsof issuingsecuritized productsusinga trustvs specialpurpose entity,(page158)
3 Describe thevarious typesof internal and external creditenhancements and
interpreta simplenumericalexample, (page 159)
4 Explain theimpact liquidity,interest rateandcurrency risk hason asecuritized
structure, and list securities thathedge theseexposures,(page161)
5 Describe thesecuritization process for mortgage backedsecuritiesandasset hacked
commercialpaper, (page163)
28.Understandingthe SecuritizationofSubprime MortgageCreditCandidates,aftercompleting thisreading,should be ableto:
1. Explain thesubprimemortgage creditsecuritization processin the UnitedStates.
(page167)
2. Identifyand describekeyfrictionsinsubprimemortgage securitization,and
assess the relative contributionof each factor to the subprimemortgage problems.(page167)
3 Describe the characteristics of diesubprimemortgage market,including the
creditworthinessof die typical borrower and thefeaturesandperformance ofa
subprimeJoan, (page 170)
Trang 10Book 2
ReadingAssignments and AIM Statements
4. Explain thestructureof the securitization process of the subprime mortgageloans
(page170)
5 Describe thecredit ratingsprocess with respect tosubprimemortgagebacked
securities,{page 171}
6. Explain die implications ofcreditratingson dieemergenceof subprime related
mortgagebackedsecurities, (page171)
7 Describe die reladonship between diecreditratingscyde and the housing cycle
(page171)
8 Explain die implications of the subprimemortgagemeltdownon themanagement
of portfolios,(page 172)
9 Compare diedifferencebetween predatory lendingandborrowing, (page 172)
29 DefiningCounterpartyCredit Risk
Candidates,after completing this reading*shouldbe ableto;
1. Definecounterparty riskandexplain howitdiffersfromlending risk,(page177)
2. Identifytypesof transactionsthat carrycounterpartyrisk, (page177)
3 Explainsomewaysinwhichcounterpartyriskcan be mitigated,(page178)
4. Definethefollowingterminology related to counterparty risk;creditexposure*
creditmigration, recovery, mark-to-market,replacementcost,asymmetric exposure,
andpotentialfutureexposure, (page179)
5 Describe the different ways institutionscan managecounterpartyrisk, (page181)
6. Describe the drawbacksofrelyingon triple-Arated* “too-big-to-fail”institutionsas
amethodofmanagingcounterparty risk, (page1S2)
7 Summarize howcounterparty riskisquantifiedandbrieflydescrihe creditvalue
adjustment (CVA).(page182)
8. Summarize howcounterpartyriskishedged andexplain important factorsin
assessingcapitalrequirementsforcounterpartyrisk, (page183)
9 Definethefollowingmetricsfor creditexposure;expectedmark-to-market,
expectedexposure, potentialfutureexposure,expected positive exposure,effective
exposure* and maximum exposure,(page184)
30.MitigatingCounterpartyCredit Risk
Candidates,aftercompletingdiisreading,shouldhe ahleto;
1 Differentiate betweena two-wayandone-wayagreement,and explain the purpose
ofan ISDA masteragreement and creditsupport annex (CSA).(page191)
2 Identifytypesofdefault-remoteenduesand describe problems associated with the
assumption that theyare in factdefaultremote, (page192)
3 Describe how terminadonand walkaway features workin creditcontracts.
(page192)
4. Describenettingandclose-outprocedures (includingmultilateralnetting)* explain
their advantagesanddisadvantages,and describe how diey fitinto the frameworkof
theISDA master agreement,(page193)
5 Describe the effectivenessof nettinginreducingexposurebasedoncorrelation
betweencontractmark-to-marketvalues, (page196)
6. Describe theeffect of nettingonexposuremetrics, (page1 96)
7 Describe collateralization and explain themechanicsof die collateralization process,
includingthe roleofavaluationagent, thetypesof collateral thataretypicallyused*
andreconciliationof collateraldisputes, (page197)
8. Describe thefollowing featuresof collateralizationagreements;linkstocredit
quality* marginsand callfrequency, thresholds*minimum transfers, rounding,
haircuts,interest,and rehypothecadon.(page200)
Trang 11Bonk 2
ReadingAssignments and AIM Statements
31.QuantifyingCounterparty CreditExposure,ICandidates,aftercompletingthisreading,should be ableto:
1. Explain thefollowing techniques used toquantifycreditexposure: add-ons,
semi-analytical methods,andMonteCarlosimulation,(page207)
2. Descrihe theMonteCarlo simulation technique for quantifyingexposure,and
explain the choiceof risk“hotspots'"on the exposureprofile, (page208)
3 Identify typicalexposure profiles for thefollowingsecuritytypes:loans, honds,repos, swaps, FX,options, and creditderivatives, (page210)
4 Explain howpaymentfrequenciesand exercisedates affect theexposureprofiles of
securities, (page212)
5 Explainthe difference betweenrisk-neutraland real probabilitymeasuresinthe
contextof how theyare usedincreditexposuremodels, (page213)
6. Descrihe theparameters used insimplesingle-factor modelsof dtefollowing
securitytypes:equities, FX,commodities,credit spreads, andinterest rates.
(page214)
7 Descrihe how nettingis modeled,(page216)
8 Defineandcalculate the nettingfactor,(page217)
9 Defineand calculate marginal expected exposure and theeffect of correlationon
totalexposure, (page 2IS)
32 QuantifyingCounterparty CreditExposure,II:TheImpactof CollateralCandidates,aftercompletingthisreading,should be ahleto:
1. Calculate theexpectedexposureandpotential futureexposureover the remargining
period given normaldistributionassumptions, (page 225)
2. Descrihe the assumptionsand parametersinvolved in modelingcollateral
(page227)
3. Identifydie impactdiat eachfactor of collateral modeling has on dieexposure
profile, startingfrom asimplecaseoffullcollateralization,(page228)
4 Explain the relevant risksinvolvedas aresult of enteringinto acollateralagreement.
(page230)
33.PricingCounterpartyCredit Risk,I
Candidates,after completing thisreading,should beahle to:
1. Explain themotivationof pricingcounterpartyrisk, (page236)
2. Defineandcalculatecreditvalueadjustment (CVA) when nowrong-way riskis present, (page236)
3 Descrihe the process ofapproximatingtheCVAspread,(page237)
4 Define and calculate the incrementalCVAand the marginal CVA.(page238)
5 Discusshow collateralization andnetting affect theCVAprice,(page239)
6. Explain challengesin pricingCVA arisingfrom the presence ofexoticproductsand
theissueof path dependency,(page 239)
7 DefineandcalculateCVA andCVA spread inthe presence ofabilateralcontract.
(page239)
8. Explain issues that need tobe considered in pricing bilateralCVA (page241)
Trang 12The fbHmvillg is i review ill the CteJil Risk MetsuKlbaiL and MiifiajÿtineciL principles designed m -address die
AIM suLemenLS set Wit by GARP® This inpie is alsu oovered in:
Topic 1 8
EXAM FOCUS
In this topic, we introduce credit riskand provide an overviewof various definitions related
tocreditrisk These definitions provideafoundation fortindersLandingcreditrisk andwill he
importanttoknow whenmodelingdais risk.The main creditrisk model discussedindais topic
is the Merton model We will discuss this model's assumptions andprohlems,and provide a
detailedanalysis of the model’sparameters.Forthe exam,paycloseattendon to thecalculations
forprobabilityof default, lossgivendefault,andexpectedloss
AIM18.1:Describesecuritieswith differenttypesof creditrisks, suchascorporate
debt,sovereign debt,credit derivatives,and structured products.
Credit denotesan economicobligation to anoutside entity that is not oneof theownersof
thefirm’sequity.Credit risk iseither the riskofeconomic lossfromdefault,orchangesin
creditevents or credit ratings
Typesof creditriskysecuritiesincludecorporateandsovereign debt, credit derivatives,and
structuredcreditproducts.Theirinterest rates includeacredit spread abovecreditrisk-free
securities.
* Corporatedebtincludes fixed and floatingratebonds issuedbycorporationsandbank
loans,andtechnicallyrepresents the only credit riskysecuritythatcandefault
* Sovereign debtisdebtissued bycentral,state, provincialorlocalgovernments, or
state-ownedorcontrolledentities.
* Credit derivativesare contracts chat transfer credit riskandwhose payoffs dependon
payoffs of other credit risky securities.Thebestknownexample ofacredit derivativeis a
creditdefaultswap(CDS).
• Structuredcreditproductsarebonds backed bypoofsofmortgages or loans or some
other typeof collateral Theyaregenerally notdefaultable, however,theyarecredit risky
indiesensethatifsomeof theunderlyingassetsdefault, thevalueof thesesecurities
musthewrittendownand thecreditormust takealoss
Trang 13Before wediscusscreditriskysecuritiesand their valuationsin greaterdetail, it isimportant
to understand the firm'sbasiccapitalstructure. In thisAIM,we will differentiate between
afirm’s bookvalueand marketvalue.Bookvaluerefers to the accountingbalancesheetof
thefirm, whereassets,debt, and equityaretypicallyenteredat book (historical)values.Thisdiffersfrom theeconomicbalance sheetof the firm, where thecomponentsof the balance
sheetarevaluedat market prices,or at someothervalue,includingoption pricing The
components of theeconomicbalance sheet also includeassetsthatarefinanced bydebtandequity(At= D( +E(},where.4 denotestheassetsof the firmat current marketprices,and
DtandEtdenotedebtandequityatmarket prices The equityratio, or E(l A(,is theratio
of equityover assets,andtheleverageratio, orAji E(,istheratioofassets overequity
Assets produce cash Howsand profits Debtis anobligation diat financesassetsand results
inaliability diat mustbe repaidin thefuture.Equityis thecapital invested by the firm’s
owners,andrepresents a residualinterest in thefirmonceall other creditors,includingdebtholders,are paid off Equity, therefore,absorbs all losses beforedebt takesaloss.Equity
owners arepaideither individendsorthrough reinvestedcapital in thefirm
AIM18.3:Identify and describe different debtsenioritiesandtheir respective
collateralstructure.
Within diecapitalstructure,differentsecuritieshave differentrights, including priority
on paymentsandcashflows Debtseniorityis theorderofrepayment on obligations—
typicallydebtor preferredshares—to creditors.Seniordehtisrepaidfirst, followed by
repayment on junior debt
Debt,especiallycorporate debt,can sometimes contain characteristicsof both equity anddebtsecurities.Threesecuritiesofnote arepreferredstock,convertiblebonds,and payment
inkind bonds
Preferred stock(i.e., prefshares) areessentially hybridsecurities that exhibit characteristics
of both bonds andequity,withapriority in dieeventof default betweencommonequity
and bonds.Similar to bonds,theypayafixed dividend and typically havenovoting rights
Similar to commonequity, theydonothaveafixed maturitydateand thereis nolegal
obligation topaydividends
Convertible bondsare bonds diatcan be convertedinto a predeterminednumberof
commonsharesduring thebonds’life As a result,it isofteneasier todiinkof thesebonds
as nonconvertible,plainvanillabondswitha calloptionon the firm’sequity.Mandatoryconvertiblebondsmustbe converted to common sharesat afuturedate(usually within
three years) Given their relativelyshortterm, the presentvalueof couponsisgenerallynot
alargecomponentof theirvalue.Oonverdble pref sharescan be convertibleinto afixed
numberofcommonshares
©2013Kaplan,Inc.
Page12
Trang 14Topic 1 8 Cross Referent* to GARPAssigned Reading-Mali*Chapter 6
Paymentinkind(PIK) bondsare bondschat payinterest in kind, asadditionalpar value
bonds, rather than bypayinginterest incash* Thisisessentiallyadeferredcoupon where die
principal increases over time*PIK bondsareoften issuedas partofleveragedbuyouts where
the issuerislookingtodefer cash payment aslongaspossihle*PIK bondsare morejunior to
regular bondsas theyincreasethe firm's indebtednessandhence itsrisk
In addition toseniority,creditobligationscanalso he categorized basedonsecurityas
eithersecuredor unsecured Unsecuredobligations only haveageneralclaim on assets in
bankruptcy,whilesecuredobligationshaveaclaimonspecificassets ascollateral* This claim
on collateraliscalledalien, which allowsacreditor to seizespecificassetsunder afirms
bankruptcy, however, the proceedscan onlybe used to pay off thespecificsecureddebt,
andcannot beused to payoff other debt Anyamountsleftover must be paidto thefirm's
owner Liens are typicallyoil realestate but can involve other securitiesincludingbonds,
firmsubsidiaries, orspecificproperty.
Othertermsassociated with secured loansincludehaircut, recourse,and priority A haircut
incollateralized lending refersto areduction inthe collateral’s valuesothat thefullvalue
of collateral is notbeinglent. Increases and reductionsin haircuts is referred to as variation
margin, while the initialamountofreductioniscalled initialhaircut.Recourse insecured
lendingreferstodie lendersrightfor claims against theborrower’sassetsbeyond thevalue
of the collateralif the collateralis insufficient cosatisfywhat die lender Isowed-Ina non¬
recourse orlimited liabilityloan, the lender has nofurtherclaim beyond the collateral value
Priority refers tothe orderinwhich claims are satisfied underaborrower'sbankruptcy
LSecured debthaspriorityover unsecureddebt, andwithin unsecureddebtseniordebt has
priorityoverjunior debt (debenturesareexamplesof junior debt)
Asset classesoutsideof cash securities(e*g., bonds,notes, corporatedebt) canalsogiverise
cocredit risk.Theseinclude derivativeson anunderlyingcash security(e.g.,creditdefault
swaps)
ProfessorsNote; Creditdefault swaps(CDS)are notthefocus ofthistopic, but
will be discussedin detail later in this book
CREDIT CONTRACT FRICTIONS
AIM18.4: Describecommonfrictions thatariseduringthecreation of credit
contracts.
Despite their advantages in mitigating credit risk,creditcontractssuffer froma numberof
problems, including transacdon costs,fricdon,and conflictsofinterest issues*
Asymmetricinformationrefers todifferent parties to a transactionhaving different
informationsets.Forexample,incredittransactions the borroweroften hasmore or hetter
information than thelender Informationasymmetriescan beremedied through monitoring
by die lender andadequatedisclosuresby the borrower
Principal-agentproblemsarisewhenaprincipal hiresan agentfor specificduties,
however, the agenthas better information dian dieprincipal Examplesinclude investment
Trang 15Topic 18
Cross Reference to GASP Assigned Reading—Mali,Chapter6
managementrelationships(e g.,an investor as the principal hiresan investment manageras
an agentfortrading, however, themanager'sincentive is to maximizeherown returns rather
chan che investor’s)anddelegated monitoring (e.g., theinterestsofa hank’sdepositorsor
creditorsas principalsconflict widr theinterestsof thebanks managersasagencs)
Riskshiftingoccurswhen risks and rewardsare transferredfrom onegroup of marketparticipants toanothergroupholdingdifferent positions inthe firm’s capitalstructure.
A classic conflictis between equity investors and lenders Equityinvestors benefitfromincreasing risktothe firm’sassets (e.g., from increasedborrowing)astheir investment Lslimitedtotheir equity while their returnpotential is unlimited, however,bondholders’
risk increases as theirreturns arefixed Therefore, risk shiftsfrom equityinvestors to
bondholders Institutions thataredeemed'koo-big-to-fail1’canalsocauserisk shifting when
risk isshiftedfrom protected debtholders (e.g.,secured or senior bondholders) toequity
holders
Moral hazardariseswhen buyinginsurance or someprotection that reduces theincentiveof
theinsured party to avoid the insuredevent.For moral hazardto arise, theinsuredparty has
theability tomitigate theriskbeinginsured, while cheinsurer cannot monitor theactions
of the insured.Aclassic exampleis the insurancebusiness.A homeownerinsuringa homeagainstlire may notpurchaseexpensive smokedetectors, or aperson with medical insurancemaynotlookafter his healthasmuchas apersonwithout insurance In finance,firms that
expect abailoutin bankruptcymayhe prompted to take greaterrisks
Adverse selection occurs when partiesto a transactionhaveasymmetricinformation.For
example, the entitysellingan asset may knowsomethingadverse about theasset that theprospective buyermaynotknow, however, this negative informationis notcaptured in the
asset’sprice In finance,abanksellingloansor securities in the markets may possessmore
information than thebuyers
Externalitiesare costs or benefits dialoccurwhenoneparty’sactions causeothers toabsorb
thecost or benefit.Forexample,asmallgroupof borrowersin the short-term marketscan
drive up thecostfor otherborrowers.Asymmetric informationarises aslenders have less
information than horrowerswhichalsocreatesexternalities
Collectiveactionproblems (i.e.,coordinationfailures)occur whenagroup of individuals
were to benefitcollectively ifthey all tooka courseofaction, butwouldnotbenefit ifan
individualalone took thesame courseofaction.Examples ofcoordination failures include
the Prisoner’s Dilemmaingame theory,or infinance where allcreditorsofa particular class
cannotagreeon termsandarealldisadvantaged under bankruptcy
DEFAULTAND RECOVERY
AIM IS.5:Define thefollowingterms relatedtodefault andrecovery: default
events,probabilityofdefault, creditexposure,and loss given default
Defaultis the failure to payafinancial obligation.Defaultincludes bothdistressedexchanges
andimpairment Underadistressed exchange, creditorsreceive new securitieswithlower
value than theiroriginalsecurities. Fromanaccounting perspective, defaultoccurswhen
the valueofafirm’sassets isless than the value ofitsliabilities(i.e., zero ornegativeequity)
Trang 16Topic 1 8 Cross Reference to GARP Assigned Reading-Mail, Chapter 6
This may giverise toimpattnipltwheretheassetvaluesare written down. Note that
impairmentcan occurwithoutdefault.Ifafirm cannotsatisfyitsliabilities, it would be
forcedintobankruptcy, which is a legal procedureinwhich diefirmseeks protection from
itscreditorseithervia reorganization and restructuring (e.g.,Chapter 11 bankruptcy)or via
liquidadon (e.g,, Chapter7bankruptcy) In reality, firmsmayseek bankruptcyprotection
before their equityisfullydiminished in ordertoallow diefirm to continue itsoperations
while preventing creditors from suingthefirm,
The probability of default (PD) is thelikelihood thata borrower willdefaultwithina
specifiedtimehorizon.Probabilityofdefaultis therefore dieprobability ofarandomdefault
time t*<T,where Tis thespecifiedtime horizon.PD isdependentondireefactors:
I Time tfrom wherewe areviewingdefault (usuallyat present or t= 0,butcould bea
futuredate)
2 Thetimeinterval overwhichto measuredefault probabilities (usually beginningat t=0
until time Tin thefuture,althoughthe intervalcouldalsobegin in die future)
3. Arandom variabletime t*whendefaultoccurs.
Exposureatdefault(i.e.,exposure)isdieamountofmoneythelender can losein theevent
ofa borrowersdefault.Exposureforderivativescontractsdependsonwhether thecontract
islinear[e.g,, futureswhich havezeronet presentvalue(NPV) at initiation] or nonlinear
(e.g.,options which almostalways havea non-zero NPV).Exposurefor swapsincluding
interest rateswapsisdieNPVof theswap
Loss given default (LGD) istheamountofcreditorlossin theeventofadefault.When
defaultoccurs,creditors typically donotlose dieentire amountof theirexposure.The
fractionof exposurenotlost (recovered) at defaultisrecovery,an amountbetween0%and
K)0%.Lossgiven defaultistherefore:
exposure-recovery+LGD
Therecoveryamount istheamountowed that creditorsreceive under bankruptcy,and
dependsonseniority,assetvalues, and business conditions Recoveryisgenerallyexpressed
as therecoveryrate,RRr where RRis afraction between 0and1
LGDrecovery
RR =
Typicalrecoveryrateslor secured debtcanexceed75%,butareoften closeto0% for
junior unsecureddebt.Both LGDandrecoveryare random variablesthatare not known
inadvanceofadefault Inaddition, LGD maybe correlated with the default probability,
which may complicate themodel.Nevertheless, many applicationstreat LGD as aknown
quantity
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Cross Reference to GARP AssignedReading—Mali, Chapter6
AIM18.6:Calculateexpectedloss from recovery rates*the loss given default*andtheprobability of default
Expectedloss (EL)is die expected value of the creditloss*and representsdie portionofloss
a creditor should provision for and treat as an expenseitem(e.g.*on theincomestatement)
If die only possible creditevent isdefault,expected lossisequalto:
EL= PD x(l —RR) x exposure = PD x LGD
Professor'sNote:In thisequation,LGD is indollar terms, however, itcould
Jiffo beexpressedas a percent(i.e., I - RR), On theexam, ifLGDisgivenas a
percent, EL = PD x LGD x exposure.
Ifdiecrediteventincludesdiepossibilityof hodi defaultand credit migration(e g.,potentialchangesincredit ratings},dien EListhe probability-weighted sumof changes in value
underdie differentscenarios.
Itisimportant to notethat bodi LGDand recoveryareconditional expectations, thatis,
theyareconditionalondefaultoccurring:
E[loss[default] =LGD=
P[default] PD
Consideranexposure of$100*000widia LGDof$30,000 thatisknownwithcertainty
The recoveryis therefore $70*000,and the recoveryrate, RR, is70%.If the probability of
default,PD, is1%* theexpected loss,EL, is 0.01 x $30,000=$300
Sowhywouldan investor invest in asecurity diat has ailexpected loss? Thesimpleanswer
is that theinvestor islookingtobecompensatedbya credit spread thatwould more than
offset theexpected loss For risk-free bonds,an investor over oneyearwouldreceive 1 + r*
wherer is the risk-freecoupon An investor would thereforeexpect to earn 1 + r+i on
a riskybond,wherezIs thecouponspread thatisexpectedto compensatefor default If
defaultcan only occur in oneyear justbefore acoupon payment,diereare twopossiblepayoffson theriskybond:
1. Tileinvestor receives 1 + r + z,with probability1 —PD
2 Theinvestor receives RR,with probabilityPD
Becausethefuturevalueof the risk-freebond isknown with certaintytohe1 + r*the
investormay prefer the riskybondaslongas:
Trang 18Topic 1 8 Cross Reference to GARP Assigned Reading-Mali, Chapter 6
CREDITVS. MARKET RISK EVENTS
AJM IS.7:Differentiate betweenacredit riskevent anda market riskeventfor
marketablesecurities
Marketrisk is die riskofeconomiclossesfrommovements in market prices,including
market pricemovementsof credit-risky securities.Credit risk isthe riskof borrower default
oncontractualobligations,bm also includesodiet risks includingcreditdowngrades.An
issuerdowngradefrom Ato BBB withoutachangein Aspreadsor interest rates is a pure
creditevent,whileawideningspread betweenAand risk-freerates or a risein risk-freerates
is a pure marketevent.Notethat there lias historicallybeensomeambiguitybetween credit
andmarket risk.Forexample,achangein theperceptionofcreditquality,evenifitdoes
not result increditmigration, maycausespreads to increaseandgive rise to credit risk (this
specificcredit riskisreferred to as mark-to-market ritk)
CREDIT ASSESSMENTTECHNIQUES
AJM18.8:Summarizecreditassessment techniquessuchascredit ratings and
rating migrations, internal ratings, and riskmodels.
A credit ratingis analphanumeric gradeassignedbycredit ratingagenciesthatsummarizes
the creditworthinessofa particularsecurityorentity.Themost prominentcredit rating
agenciesareStandard andPoor’s (S&P),Moodys, and Fitch Ratings (Fitch), which have
been grantedspecial recognition bytheSecurities andExchangeCommission (SEC) in die
U.S.
Theratingsassigned by thecredit ratingagencies reflect the probability of default of
entitiesand debt issues AAA securitiesareconsideredvirtuallyfree ofdefaultrisk, while
aD ratingsignifiesdefault.Investmentgradesecuritiesrange from AAA to BBB-,while
non-investment (i.e.,speculative)gradesecurities range from BB+ to C.Rating agencies
alsoassessrating migration,orchangesin ratings Probabilityestimates aresummarizedin
transition matrices,whichshowdieestimated likelihoodofa rating change foracompany
within aspecified time period(usuallyoneyear) In other words, thematrix indicates the
probability thataparticular issuerwillenddie period withadifferentratingthan what
itinitially beganwith Atypical1-year ratings transition matrixbyS&P can beseen in
Figure1.
Trang 19Topic 1 8
Cross Reference to CARP AssignedReading-Mali, Chapter 6
Figure 1: Transition Matrix
0.48
The largest percentages within thematrix areshownby diediagonal figures startingfrom
topleft, which show the probability that securities would finishayearwith unchangedratings Forexample,diereis a91.43%probabilitythat asingleA-ratedsecurity would
maintain itsAratingat theend of the year Note diat theprobabilityoffailureincreases
considerablyasthestartingcredit rating foils.Also,defaultisconsidereda terminal state;
thatis,diereis no transitionfromdefault
Itisimportant to understandthat die ratingsbusinessgives rise to an inherentconflictof
interest.Ratingsagenciesarecompensated for ratings by bondholders rather than by die
saleof datato investors(thisiscalled the issuer-pays model).Thisgivesrise to aconflictbetweenbondissuers,who benefitfrom receivingdiehighest ratings, and investors,who
expectratings to be basedon anobjectiveratingsmethodology.Pardydue to thisconflict,many firms carryout theirown internalassessmentof credit quality throughinternal models,andmay assign internaltarings to assistwithcredit-relatedor investmentdecisions
Credit riskmodelsarefrequently used to assesscreditriskofasinglefirm The two main types of modelsare reduced-form modelsandstructural models.Reduced-form modelsare
technicallynotrisk models whichestimatedefault probabilitiesor LGDas outputs,but
radier use dieseparameters asinputs to simulatedefault times.Structural modelsestimate
credit riskfrom fundamental inputs primarilyfrom balance sheetdata,
AIM 18.9:Definecounterparty risk, describeitsdifferentaspectsandexplain how
it is mitigated.
AIM18.10: Describe howcounterpartyriskisdifierentfrom credit risk
Counterparty riskis a typeofcredit riskthat oneofthe partiesto a transactionwillnot
fulfillitsobligations.In evaluatingcounterpartyrisk, twoconditionsmust besatisfied:(1)
the investment must be profitable,and (2) thecounterparty mustfulfill itsobligation to die
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Trang 20Topic 1 8 Cross Reference to GARP Assigned Reading-Mali, Chapter 6
investor However, counterparty riskistypicallya two-way transaction withdie linebetween
borrowerand lenderblurred Thistypeof risk mayariseunder thefollowingscenarios:
1 OTCderivativestrading.Each derivativescontracthas twosides,andeidier side may be
exposed to counterpartyriskatanygiven time. Inaddition, OTCderivative tradesare
bilateralcontractsbetween twoprivate parties,whichcreates counterpartyriskatany
given time.In contrast, exchange-tradedinstruments,includingoptionsandfutures,
have significantly lesscounterpartyrisk given thataclearinghouseis atdiecenterof
each trademitigatingdiis risk
2. Brokeragerelationships.Historicallyit wasassumedthatonlythe brokerin abrokerage
reladonship hascounterpartyrisk, not the client Followingthesubprimecrisis,this
assumption haschanged followingclient lossesfromfailed brokerages,while broker
lossesonclientexposuresremained rare.
Nettingsignificantly reducescounterparty risk Nettingbecomes particularlyimportant
aspartiesfrequently trade multiplepositionswith eachother,often buying and selling
differentquantities of thesame contract widiina day Nettingprovidesagainto bodi
partiesasonly thenet amountof money needs tohe paid, reducingcounterparty risk
Multilateral nettingisnettingamongmuldplecounterparties.Exposuresunder multilateral
netdngare moredifficulttocalculate,however, thebenefitsaresimilaras under netting
Nettingandsetdement clearingaretheprimary reasonswhy clearinghouseswereintroduced
in the U.S infuturestrading.In addidon,counterpartyexposures and nettingareoften
governedthrough legal agreements including theISDAMaster Agreement
Itisimportanttodistinguishcounterparty riskfrom market risk Market riskis the risk
chat the valueofan underlyingposition willmoveagainst die trader due toadverse market
factors, which mayresult in a negative NPV of dieinvestment. Counterpartyriskis the
conditional risk chat dieNPVof theinvestment ispositive, however, thecounterpartyfails
to perform itsobligationsand therefore no profitisrealizedfromthetrade Toaccountfor
counterpartyrisk, the fair NPV ofthe positionmust be adjustedbya counterpartycredit
valueadjustment(CVA).
Onewayto protectagainstcounterparty riskin derivatives trading ismargin Marginis
aform of collateral posted by both counterpartiesto cover potentiallossesfromdefault
Initial marginistheamountof cash collateral posted by both sidesat tradeinitiation Initial
margin tends tobe small, particularlyfor mostswapcontracts,and the majority of margin
arisesfrom changesin theNPVofderivativescontractswhichareposted dailyas variation
margin.Notall cypesoftradeshave small initial margin, however Contractsincluding
CDSsandCDS-related tradestypicallyhavelargeinitial marginasthesecontractsrequire
significant upfrontpayment inexchange for tirecounterpartysellingprotection
Historically, derivativesdealers rypically required their clientsto postinitial marginon both
thelongand short sidesofaswap Itwasalso thedealer LhatconsideredmakingCVAs to
OTCderivatives, rather dian die client,to protect the dealer againstpotentialclientdefault
During the recentcreditcrisis, however, including the bankruptcy of LehmanBrothers,
the assumptions of such one-sided protection proved incorrect.Clients suffered significant
lossesas aresult of Lehman’sdefaultsinceLehman held margincollateral,which then
became partof diebankruptcyestate.This resulted in clientsbecoming unsecuredgeneral
creditorsof the Lehman bankruptcyestatefor both diemargin paid toLehmanandfor
their claimsfrom die derivativecontracts.
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Cross Reference to GASP Assigned Reading—Mali,Chapter6
Counterparty riskcan he mitigated by: (1) accurately measuringexposures, (2) maintaining assessmentof counterparty conditions, (3) dealingwithadiverse groupof counterparties,
and(4) minimizing exposurestoweaker counterparties
Reducingexposuresto aparticularcounterparty can beachieved bylimiting the volumeof
OTC contracts tradedwiththem, orhy increasing the amountof collateral requirementsagainsL them In thecontextofCDS trades, limiting the volume oftrades to a counterparty
isreferredto as CDS compression.When dierearemultiplelongand shortCDSpositionswitha counterparty,compression reducesthesetofCDStrades to asinglenet longorshortposition, which limitsexposuretothecounterparty.LSomedifficulties couldarise,however,
as contractsmay notbe identical regardingcounterparty, premium,andmaturity
VariationsofCounterparty Risk
Double default riskis the risk that a counterpartythat solddefault protectionon a third
partywill defaultatdiesame time asthe third party.Therefore,doubledefaultrisk isbodi
aform ofcounterparty riskandcorrelationrisk Oneof thebest-knownhistoricalexamples
ofdouble defaultriskwas thecaseofAmerican International Group(AIG).AIGis awellcapitalized,highly ratedUA-based insurance corporation thatsold significantamountsof
CDS protectionon avariety ofcreditexposures.Given AIG'sprominent market position,
the protection buyersconsideredcounterpartyrisk (i.e.,the potential forAIG todefault) to
be minimal Tooffsetitsexposures,AIG, diroughoneofitssubsidiaries, purchasedalargequantityofhighly rated mortgage-backedsecuritiesincluding collateralized debt obligations
(CDOs) Asthe credit crisisunfolded,AIG was unableto meet itsobligations under the
CDS contracts ithadwritten atdiesame time itsufferedmaterial impairments under theCDOcontractsitheldlong
Custodial riskrefers to the riskofdefaultbyacustodian.Custodians provide custodial
servicesbycollectingcash flowsincludingdividendsandinterest,and selling, lending,and
transferringsecurities tobe availablefor delivery.Custodiansalso maintaincustody of
securities inmarginaccounts inmarginlendingand primebrokeragerelationships.This
gives rise tocustodialrisk,as securities in marginaccounts are not in thecustomer’s name
but areinstreet name so that they could besold immediatelyto protect the lender againstpotentialcredit losses Thiscontrastswith securitiesincash and nonmarginaccounts,which
areincustomer nameandarethereforenotsubject tocustodial risk
Brokersoften providecustodialservicesinaddition to credit intermediationservices to
clients Collateral pledged byaclient that isheld bythe broker can oftenbe repiedged
by the brokerascollateral toborrow moneytofundits ownoperations Thisis referred
to asrehypothecation Rehypothecation becameaparticular concernduring the Lehmanbankruptcy as theassets, including unpledgedassets,of clients ofoneof Lehman’s
subsidiarieswere notsegregatedandwere thereforesubject torehypothecation.Asa result
theseclients becamecreditorsof Lehman duringthe bankruptcyproceedingsas potentially
Trang 22Topic 1 8 Cross Reference to GARP Assigned Reading-Malz, Chapter 6
AIM18.11:Describe theMerton Model,anduse itto calculate the valueofafirm,
the values ofafirm’s debt and equity, and default probabilities.
Single-obligorcredit risk modelsaremodelsofasingleissuerof debt obligations.The model
chatisour primaryfocus is dieMerton model,which relates the firmls balance sheet
components tocredit riskusing the Black-Scholes-Merton option pricingmodel in order to
value credu-riskycorporatedebt.TheMerton model rests on anumberofassumptions:
1. The marketvalueofassets, and expectedreturn, p,arerelated Markets are in
equilibriumandinvestors expect to earn ariskpremium of p—r,wherer isdie
continuouslycompoundedrisk-free rate.
2 The basicfunctionofA( = E( + D(describes thefirm's balance sheet Debt consistsof
asinglezero-coupon bondwithanominal paymentof D,maturingat rime T.The
notation D refersto thenotionalvalue of debt, whileD(andEt indicatethevalueof
debtandequityat time t (marketvaluesofdebt andequity}.The model alsoassumes
that thefirmcandefault onlyon thematuritydateof die bond
3. Equityconsistsofcommonsharesonly
4 Debtholdershavelimited liabilityandhave no recourse toanyoiher assets onceequity
iseliminated
5 Contractsarestriedyenforcedand debtholder obligationsmust be fully satisfied before
equityowners canrealize any value Note diat thisassumptionissomewhat unrealistic,
asthereare typicallynegotiationsbetween debtholdersand equityowners onhowto
distributeassetsifafirm isundergoingreorganization
6. Tradingin marketsoccursnotonly for the firm's equity and dehtsecurities, but alsofor
its assets.Traderscanestablish hodilongand short positions
7 Thereare nocash flows priorto diematurityof the debt (includingdividends).
Default occurswhen the market valueof the firm'sassets isless chan theface value ofits
obligations,or whenAj-< D.Aq-—Discalled the distancetodefault.Therefore,we can
view the firm's debt and equityasEuropeanoptionson thevalueof the firm'sassecswith
diesame maturitybisthe firm’s zero-coupondebt.Optionscan then be Vbdued using the
Black-Scholes-Mertonoption formula,althoughcontrary to typicaloption pricingmodels,
herewe arelooking covaluecredit risk
Professor's Note:For thistopic,you are notrequiredto usethe
Black-Scholes-Merton (BSM) modelto valueoptions Calculations usingBSMwill he
demonstratedin Topic20. Yourfocushere should heon how to useprovided
option valuesto value thefirm'sdebt andequity
As mentioned,thesetof assumptions just outlinedis notentirelyrealistic, including the
assumption ofanabsenceofnegotiationsbetween debtholders andequityownersduring
Trang 23Topic 1 8
Cross Reference to CARP AssignedReading-Mali, Chapter 6
reorganization In addition,it is unrealisticto assumethat thevalueandvolatilityof die
firm'sassetswould beknownatanygiventime.
Nowthatwehaveoutlined thesetofassumptions, equityanddebtvaluescan he computedusingoption-pricing modelsasfollows:
Equity valueoffirmzThe valueofassets, and thevolatilityofassets, are seen as
known quantities Equitycan he viewedas acall option on the firm'sassetswithan exercise
priceequal toD.Atmaturitydate T,if thefirm'sassets are greaterthan itsdebt, the firm
pays thevalueof debt.Ifthe valueofassets islessthan the value of debt, equity is zero
and the firm doesnot have sufficientresources topaydebtinfull The valueofequityat
maturitydate Tcan then beseen as:
Ep = masfAp- D,0)
The notation T=T- t represents thetime to maturity, and thecurrentvalueof equity,Et,
can then he valued using die Black-LScholes-Merton value ofaT-yearEuropean callat a
D(=De rr -(European putvalue with strikeat D)
Thefirm'sbalance sheet The halance sheet equation ofA( =Eÿ+ D(can be re-written asdie
valueofa portfolio of the risk-free discount hond plus along call anda short putoption
withstrike prices of thenominal valueof debt:
A(= E(+D(= (European call with strikeat D)+ De rr -(European putwith strikeat D)
Leverage*.Leverageissimplytheratioof equityto assets.
Probabilityofdefault(PDfi Theprobability of defaultis theprobabilityof exercising theput
and call options Itisimportant, however, todifferentiate between crue/actuarial/physicalprobability ofexerciseand therisk-neutral probability
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Trang 24Topic 1 8 Cross Reference to CARPAssigned Reading-Mali, Chapter 6
The actuarial(true orphysical)PDcan becalculated using astochastic process usingthe
return on assets, p PD can then he calculatedusingalognormaldistributionofthefirths
assetswidi parameterspand oA:
Yieldtomaturityand creditspread:"We can nowalsocalculate dieyield to maturity of debt
and.itscreditspread-Theyield tomaturity of debt,yt is:
DteÿT =D
Theequation canbe re-arranged usingthecurrent market valueof die debt:
[De-rr-Europeanput optionwith strikeat D]ey tT= D
Aftertaking logarithms, the formula becomes:
yt — — logjÿl—e pEuropean putopdonwith strikeatDj
Finally,we can calculatethe creditspreadbysubtracting the risk-freerate from both sides:
r= —log|ÿ1 — e-1"7ÿ +European put optionwith strikeat Dj -r
yt-Loss givendefault(LCD): TheLGD dependsonhowmuchthe valueof the firm’s debt
exceeds the valueofassets atmaturity.In theMerton model, LGD is arandom variable
Note that theactuarial expecteddefaultlossis not thecurrentmarket valueof the put
opdon Rather, the value of theputopdonis greaterthan die actuarialexpected loss given
thecompensation to die put writerfor cakingon the risk and expectedcostof default
protection The actuarialexpecteddefaultlossescanthen he calculated as thefuture valueof
the actuarialdefaultputoption:
expecteddefaultlosses=erf (European putoptionwithstrikeat D)
Trang 25Topic 18
Cross Reference to CARP AssignedReading-Mali, Chapter 6
Dividingtheactuarialexpected default lossesbythe PD gives ns the LGD:
je1"7 (European putoptionwith strikeatD)j
expectedLGD
PDFinally,we can compute theexpected recoveryrate as:
(expected LGD)
1
Profestor'sNote:The Merton model will be reviewed Again in Topics 19and20
AIM18.12:Explain the drawbacksand
Merton Model,andidentifyproprietary models of rating agencies thatattempt to
address these issues
possible improvements to the
assess
Asmentioned in the previousAIM,the Merton model makessome unrealisticassumptions
Another drawbackof the model is that itcouldresult inlow default probability valuesand
high recoveryratesfor firmswithhighleverage.Firms widihigh leveragein realitywould
typicallyhavehigherdefault probabilitiesand lower recoveryrates.
Despiteitsdrawbacks, the Merton model has provedpopularandhasbeen adapted
byseveralratingagencies in theirproprietary models,including Moody’sKMVand
RiskMetries’CreditGmdesmodels Thesemodels address theMerton model’s two main
shortcomings: (1) afirm's capitalstructure,especiallyitsdebtstructure, isgenerallymuch
morecomplex than themodelimplies, and(2) afirm’s assetvalueandvolatilityis not
direedyobservable in die market
CREDIT FACTOR MODELS
AIM18.13: Describe credit lactor models and evaluatean example ofasingle¬
factor model
Factormodels relate the riskof credit losstofundamentaleconomicquantities Asimple
versionofafactor model is asingle-factor model,which usesa randomassetvaluefrom the
Merton modelas thevaluebelow which thefirmdefaults
Asingle-factormodelcan beused tovaluea firm’sasset return.Withahorizonatthefuture
dateof T ™ t + T, asset return canbecalculated usinga logarithmicformula:
Trang 26Topic 1 8 Cross Reference to GARPAssignedReading-Malz, Chapter 6
As weyepreviouslyseen,defaultoccurswhenAp< D.Thisisthenidentical to theevent
that;
D~A/ =
, A , -MfeH -log(equity ratio]
aT <log
In ocherwords,defaultoccurswhen dieasset return isnegative andgreaterinabsolute value
chan the initial equityratio(E, t A().
Asset return under this model is afunction of two randomvariables: (1) the return on a
marketfactor m that denotes the correlation between default and thestateof the economy,
and(2)ashock E-t thatcapturesidiosyncratic risk.Asset returnand thevarianceofasset
return can thenbe written asfunctionsof dieasset betas:
a-p — 3m "H>/l — 0ÿ£
Var[aT] = 0ÿ +1-/?2 =1
The0in themodelabove relatesto assetbeta radier thanequitybeta andcaptures the
co-movement of the firm’sreturnswithan unobservable market index
lasdy, thesingle-factor model uses adefault probabilityas an input(rather than an output
as under the Merton model) that values thedefault diresholdassetvalue (denotedas k)
based on the /'Z?-th quantile of usingastandard normaldistribution function.In
summary, thesingle-factor modeluses two parameters,8and£, whichcan heestimated
usingbalance sheetdataandstock price informationorfirmratingsandtransition matrices.
A practicalexample of the model would hetocalculate thevalue of0wheresystematicand
idiosyncraticrisk contributeequallyto total credit risk, as measuredbyreturn variance This
would heat a0valuewhere:
CREDIT VAR
AIM18.14: Define Credit VaR (Vaiue-at-Risk).
CreditVaRandthe previous models for estimatingcredit risk statistics(e.g., unexpected
loss) arerelatedbecause they incorporatepotential losses at afuture dateat agiven
probability Theydiffer, however,in two main respects First,thetime horizonfor
measuringcredit riskis typically muchlonger than for marketrisk,andisgenerallyaround
oneyear.As aresult, creditdriftforcredit riskcan be material andcanalsocreateissues that
areusuallynot a concernwidi market risk,includingdie treatmentof coupon payments
andcostoffundingpositions.Second, extreme skewness is amaterial concern in credit risk
Extremeskewnessarisesgiven,in the rare eventthatdefault doesoccur, returns arevery
Trang 27Topic 1 8
Cross Reference to GARP AssignedReading-Mail,Chapter6
large and negative Skewness resultsin a higherconfidenceintervalfor measuring credit
VaR,usuallyat99th and99.9thpercentiles
Onceacreditloss occurs,losses can he broken down into threecomponents;expected
loss, unexpectedloss, and tail loss (lossbeyond unexpectedlosses).Expectedloss(EL) is thedifferencehetween die par valueofa bond and itsexpected futurevalue,factoringin
default probability andrecovery Unexpectedloss(UL) is aquantile ofcreditlossin excess
of expected loss,defined eitherasstandarddeviation ordie99thor99.9tb percentileloss
inexcessof expected loss.CreditVaRistypically definedin termsofULastheworst-case
portfoliolossat agivenconfidencelevelover aspecific holding period, minus the expectedloss This differs Irorn market risk, where market risk VaR isdefinedin termsofprofitand
loss,thatis,it comparesafuturevalue witha currentvalue.Credit riskVaR compares two
futurevalues
Jump-ta-defaultriskis an estimateof the lossifa position were to immediatelydefault
The jump-to-default value ofJC units ofabondwithavalueofpisxpRR,where RRis therecoveryrate.Notethat jump-co-defaultriskcanalso becalculated widioutdefault
probabilitiesas a form ofstress testing, by lookingat it as a worst-case scenario. Notethat
jnmp-tn-defaiilt riskcanbe misleadingfor portfolios for two reasons First, a portfolio
withlongand short positions thatareoffsettingwill haveartificiallylow jump-co-default
valuesalthough portfolio riskishigh.Second,aportfolio with only longpositionswill showartificially highjump-to-defaultvaluesas itdoesnot factorin diversification
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Trang 28Topic 1 8 Cross Reference to GARP Assigned Reading-Malz, Chapter 6
KEY CONCEPTS
AIM1S.1
Creditis an economicobligationto anoutsideentitythat is not oneof theownersof the
firm’sequity.Creditrisk iseither the riskofeconomiclossfromdefault,orchangesincredit
events orcredit ratings Credit riskysecuritiesincludecorporateand sovereign debt, credit
derivatives,andstructuredcredit produces
AIM 18.2
Afirm’s bookvaluerefersto theaccounting balance slicetof diefirm, whereaseconomic
balance sheet of the firm refers to thecomponentsof the balancesheetvaluedat market
prices.Accordingto the basic balance sheet equation,assetsequaldebtplusequity The
equityratio isequityover assets,and die leveragerado is assets overequity
AIM18.3
Debtseniorityis die orderof repayment onohligadonsofsecuritieswithinafirm’s capital
structure.
LSecurides canincludehybrid securities thathave characteristiesof bothequidesanddebt,
includingpreferredshares, convertiblebonds andpayment in kind bonds
Unsecured ohligadonsonly haveageneral claimon assetsin bankruptcy, while secured
obligationshaveaclaimonspecificassets ascollateral
AIM18.4
Despitetheiradvantages, creditcontractshaveanumber of drawbacks,including
asymmetric information,principal-agent problems, riskshifting, moralhazard problems,
adverseselecdon, externalities,andcollectiveaction problems
AIM18.5
Defaultis die failuretopayafinancialobligation andincludesboth distressedexchanges
(creditors receivenew securities with lowervaluedian their originalsecurities)and
impairment (assetvaluesare writtendown)
Probabilityofdefault Is the likelihood that aborrower willdefaultwithin aspecified time
horizon.Probability of defaultisdependenton dietimefrom wherewe areviewingdefault,
thetimeintervaloverwhich tomeasuredefault probabilities,andarandom variabletime
when defaultoccurs
Exposureatdefaultis dieamountof money the lendercanlosein theeventofaborrower’s
default
Loss givendefault (LCD)is theamountofcreditorlossin theeventofadefault.LGD is
essentiallyexposurelessrecovery.Therecoveryamount istheamountowed that creditors
receive underbankruptcy,anddependsonseniority,assetvalues,andbusinessconditions,
Trang 29Topic 1 8
Cross Reference to CARP AssignedReading-Mali, Chapter 6
AJM 18.G
Expectedlossis die expectedvalueof die creditloss, andisequal to the probability of
default times LCD.Creditmigration referstothe potentialchangesincredit ratings BothLCDandrecoveryareconditionalexpectations
AIM IS.7
Market riskis the riskofeconomiclossesfrom movementsin market prices.Credit risk is
the riskof borrower defaultoncontractualobligations,and includes other risks likecredit
downgrades
AIM18.8
A credit ratingis an alphanumeric gradeassignedby ratingagencies that summarizes the
creditworthinessofaparticular securityorentity
Ratingmigration refersto a changein ratings.Probabilityestimates aresummarizedin
transition matrices,which show the estimatedlikelihoodofa ratingchangeforacompanywithinaspecifiedtimeperiod-Theratingsbusinesssuffers from conflicts ofinterest,
includinga conflict between bondissuers and investors.
AJM 18.9
Counterpartyriskis a typeofcreditrisk thatoneof theparties to a transactionwillnot
fulfillitsobligations.Twoconditionsmust bemet inevaluatingcounterpartyrisk:(1)die
investmentmust beprofitable,and (2) thecounterparty mustfulfill itsobligationtodie
investor
AIM18.10
Credit riskis either the riskofeconomiclossfromdefault,orchangesincreditevents
or creditratings.Counterparty riskis a type of credit risk thatoneof die parties to a transactionwill notfulfillitsobligations.Market riskisthe risk that the value ofan
underlyingposidon will moveagainst dietraderdue toadverse marketfactors
AJM 18.11
TheMerton modelis asingle-obligorcredit risk model that relates the firms balance sheet
components tocredit riskusingthe Black-Scholes-Merton opdon pricingmodel inorderto
value credit-riskycorporatedebt.TheMertonmodelrests on anumberof simplifying and
at times unrealisticassumptions
AIM18.12
TheMerton model hasbeenadapted by several radng agencies in theirproprietary models,
including Moody’s KMVandRiskMetrics'CreditGradesmodels, whichcorrectseveralof
theMertonmodel’sshortcomings
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Trang 30Topic 1 8 Cross Reference to GARP AssignedReading-Mali, Chapter 6
AIM IS.13
Factormodels rek.ee[he risk of credit losstofundamentaleconomicquantities A
single-factor modelcanhe usedtovalueafirmsasset return anddefaultevents.
AIM18.14
Unexpected losses and creditVaRare relatedconcepts sincethey bothincorporatepotential
lossesat afuture dateat a given probabilityhowever,differin that dietimehorizonfor
measuringcreditriskistypically muchlonger than for market risk, andextremeskewnessis
a materialconcern incredit risk
Lossesfollowingacreditlosscan be broken downintoexpectedloss,unexpectedloss,and
tail loss (lossbeyond unexpectedlosses)
Trang 31Followingtheaggressive risk-takingbyoneof the largestAustralian hedgefunds, the
sis month AustralianLIBOR ratehas increasedfrom 3.5% to3.8% Which of the
followingeconomic termsbest describes thisscenario?
JemisFund Management Inc (Jemis)is amutual fundcompany diatfrequendy
tradesinterest rateswaps.Oneof the swapscurrentlyoutstandinghasa net present
value(NPV)of $2 millioninJemis7favor.AccordingtoJemis, the$2million
represents itspotentiallossintheeventof the counterparty's default Which of thefollowing termsbest describes this amount?
A. Exposureatdefault
B Recovery
C Expected loss
D Loss givendefault
A bank hasanoutstanding tradewith oneofitscounterpardeswith anexposure
of$500,000andarecoveryrateof 70%.Thehankestimatedthat thereis a2%
probabilitythat thecounterpartywill defaulton itsobligations.Whatisthe bank’s
A Transition matrices assessrating mlgradons, dialis, the probability thata
company starting with aparticular ratingwill hedowngradedwithin thestated
period
B Thediagonalelements in the transition matrix beginningat thetopleft show
theprobabilityofending the year withan unchanged rating
C Withina transition matrix,thereis no transidonfromdefaulttoanother rating
D The probabilityofarating migrationislowerfor lower raied companies
Foradditional Book2 Topic18practice questionssee:
SelfTestQuestions: #1—2(page247)PastFRM Exam Questions:#1(page252)
5
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Trang 32Topic 1 8 Cross Reference to GARP AssignedReading-Malz, Chapter6
CONCEPT CHECKER ANSWERS
1 B The film’s equity is its assets less itsdebt*or $258,800-$150,000=$ 100,000,
The equity ratio is the ratio of equity to assets, or $100,000 l $250,000=0.4.
Theleverageratio is the ratio of assets to equity, or $250,000!$100,000 n2.5
2 C This scenario is anexampleof anexternality.Externalities arc costs or benefits that occur
when one party’s actions cause others to absorb the cost or benefit In this case, the aggressive
risk taking of one entity lead to an increase in short-termborrowingcosts for adprudent
borrowers in theAustralian fendingmarket
3 A Exposureatdefault(exposure)is thepotentialamount lenders would lose in the event of a
borrower’s default, Exposurefor interest rate swaps is the NPV of the swap Lossgivendefault
(LCD) is the amount of creditor loss in the event that a default does occur, and is calculated
as the exposure less recovery The fraction of exposure not lost at default is recovery.Expected
loss is theexpectedvalueof the credit loss, and is a factor of theprobabilityof default and
LGD.
4 A At a recovery tare of 70%, the recovery amount is $500,000 x 0.70=$350,000.
The loss givendefault(LCD) is $500,000-$350,000 =$1 50,000.
Expectedloss is(probabilityofdefault x LGD)=0.02 x$150,000=$3,000.
5 A Transition matrices assess theprobabilitythat a company’s rating will remain unchangedat
the end of astatedperiod.Rating migration measures theprobabilityof achangein letter
rating, however it encompasses both ratingupgradesanddowngrades
Trang 33The fallowing is n review of the Qtiiii Riik Measurement and Management principles designed to address die
AIM statements set forth bv GARP®, This topic is also covered in:
METHODOLOGIES
Topic 19
EXAM FOCUS
In this topic,wewill discussmethodsfor computingdefaultrisk The Mertonmodelestimates
die value of the bondholder andstockholder claims, which are then used to calculate the
implied probability of default However, diis model requires many unrealisticassumptions
Moodys KMV model relaxes some of diese assumptions Other methods used to predict
defaultarecreditscoring models,includingparametricmethods andnonparamerricmediods.Note that the Merton model and die KMV model will hediscussed in greater detail in the
nexttopic{Topic20).Fordieexam,understand how theKMVmodel calculates probability of
defaultand haveageneral understanding of the credit scoringmodels discussed
AIM 19.L:Describe theMerton modelforcorporate securitypricing, includingits
assumptions,strengths and weaknesses:
* Illustrate andinterpret security-holder payoffsbasedontheMerton model
* Using theMerton model,calculate thevalueofafirms debt and equity and thevolatility offirm value
* Describe the resultsandpractical implicationsofempirical studiesthatuse theMerton modeltovalue debt
Professors Afate: The lasttwo bulletpointsfromAIM19.1 will be addressedin
Topic20.
Structuralmodelsof credit riskestimatedefaultriskas afunctionof thevalueof the firm
Given thevalueof the firm, the valueof debt and equitycan bedetermined Structuralmodelsin thiscontext arealsocalledvalue-based models
The Merton model isconsideredavalue-based model, where thevalueof the firm’soutstanding debt(D)andequity (£) areequal to the valueof thefirm{V}.Given an estimateofanytwo of the three values (V, E, orD),weknow the valueof the third
component. Forexample, given thefundamentalvalueof thefirmand the observed value
of diestock,ananalystcandetermine the valueof the bonds: D=V-E Also, given Vand other information, D and Ecan hedetermined.The valueof the debtcan serve as an
indicatorof the firm’sdefaultrisk.
SinceEandDarecontingentclaims,option pricingcan be used todetermine theirvalue?
TheMerton modelassumesthat the debt consistsofasinglezero-couponbond issuethat
matures at timeMatface value£>M.Atthe maturity of thedebt, ifthevalueof the firm’s
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Trang 34Topic 19
Cross Reference to GARP AssignedReading—de Servigny Sc Renault, Chapter 3 assets isless than the value of the debt, then thefirm mustdefault.Thedebtholdersget
thevalueof thefirm, and they either breakeven or takea loss,while the equityholdersget
nothing.Thepayoffsatmaturityare asfollows:
payment todebtholders= Dw-max(DM-VM,0)
payment tostockholders- max(VM-DM,0)
The Mertonmodelassumes that Vfollowsa certaindistributionover time,such that the
valueof the stockholders’ claimcan bedeterminedby the Black-Scholes-Merton option
pricingmodel.This isbecausethe payment to the stockholdersatmaturityislike diepayoff
ofalongpositionin acall option The payolfofacall option isdenotedwith thefollowing
expression: max(priceof stock—exerciseprice, 0).Thedebtholders’payoff resembles that of
ashortputand risk-free bond
The relationship of theMerton model to the Black-Scholes-Merton modelrequiressome
other strong assumptions (e.g., the bondholderscannotforcebankruptcyprior to maturity}
the valueof thefirm, V, isobservable and follows theassumed time-seriesprocess; etc.)
Ifwe canassume theMertonmodelisvalid andthat theassumptions hold,we can use
the previous equationsto computethe payoffs For example,wewill assumethe bonds
haveamaturity,orfacevalue,of $80 Ifweconsidera case where the value of thefirm is
$200 when the bondsmature,then the payofftostockholdersis$120,and thepayoffto
bondholdersis $80,In anothercase, if thevalueof thefirmis $70,then thedebtholdersget
$70, and die stockholdersget$0 These resultsrequire theassumption that noadjustment
forliquidityisneeded
Diagrams of thepayoffs resemble thoseof option payoffs Figure1shows that thepayoff to
bondholders (D) increasesone-for-one with thevalueof thefirm (TO, D = V,untilV> DM,
when the maximum payofftothebondholders(DM)isreadied The payoff toshareholders
(.S)beginsat the pointwhereV= DMandincreasesdollar-for-dollarwith thefirmvaluefor
firmvaluesaboveDM.Itcan be viewedas acalloptionon firm value withan exerciseprice
ofDm, tiie maturity value of the debt
Figure1:Payoff to BondholdersandShareholdersatMaturity
Payoff to bondholders Payoff to shareholders
S D
DM
D* Firm Value Firm VaJue
Trang 35Topic 1 9
Cross Reference to GARP AssignedReading-de Servigny & Renault,Chapter3
Thestrengthsof theMerton modelare itssimplicity when pricingcorporatedebt,aswell
as its intuitive nature.The weaknessesaredie numberofassumptions required,aswellas some practicalityissues. Forexample, the absenceofmarked to marketdebtvalues makesit
difficult toaccurately value thefirm In addition, itcanalso be difficult to hndan accurate
estimateofassetvolatility
AIM 19.2:Describe the Moodys KMVCredit Monitor Model toestimate
probability'of defaultusing equityprices, andcomparethe Moodys KMVequitymodel withthe Merton model
Batiks use theMertonand dieKMV approachtodeterminedefault rates.Default rate
informationis necessaryto determine die required capital needed to coverlosses Thefollowingis adiscussionof diesourcesoferror in thedeterminadonof default ratesusingthese methods
The Merton model usesmarket datasuch asstock value andcapitalstructure topredict
racesofdefault.TheMerton model relieson alistofunrealisticassumptions:
1. Thereisonlyone issueof equity and debt, andthedebtis intheform ofazero-coupon
bond that matures at agivendate.
2 Defaultcanonlyoccur at thematuritydace
3 The value of the firmisobservable and followsalognormal diffusion process(geometric
Brownian motion).
4. Therisk-freeinterest rate is constantthrough time.
5 Thereis nonegotiationbetweenequityand bondholders
6 Thereis noneedtoadjust for liquidity
The KMV model isbuilton the Merton model andtries toadjust forsomeof die
shortcomings,mostnotably (1)that all thedebtmatures at the same timeand(2) that the
valueof thefirmfollowsalognormal diffusion process
The KMVmodelassumes that thereareonly twodebtissues;die firstmaturesbefore thechosen horizon, and theochermaturesafter chat horizon The maturity value,ordefaultthreshold,is alinear combinadonof die values.Thedefaultthreshold (a.k.a thedefaultpoint)is in essencethe parvalueof the firm’sliabilities (or debt) In other words, thedefault
thresholdis acombinationof short-termandlong-term liabilities
Apractical rule fordeterminingthedefaultpoint (i.e.,default threshold)is:
short-term liabilities+0.5x long-termliabilities
Trang 36Topic 1 9 Cross Reference to GARPAssigned Reading—de Serrigny & Renault,Chapter 3
Thisequation isapplicable when dieratioof long-term-liabilities-to-short-term-liabilities
isless than 1.5- Ifthisratio is greaterthan 1 ,5,die default point would bedeterminedas
follows:
0.3 x shore-termliabilities
long-termliabilites
Beforewe cancalculate the probability ofdefault using theKMV model,we mustderive the
distancetodefault (DD).The DD considers die distribution of the firm’sasset returns and
calculatesthe numberofstandard deviationsbetween themean of theassetdistributionand
thedefaultdireshold In equation form:
expectedassetvalue-default threshold
asset value
DD
Professor's Note: Onprevious FRMexams, the distanceto default has been
calculatedusingthefollowing expression:(asset value-liability value)l
(standarddeviation ofasset valueindollar terms).
Once die distance todefaultiscomputed, the expected default frequency(aÿk.a.die
probabilityof default) can be found We willsoon seehow the expecteddefaultfrequency
figureismapped onto acredit ratingsystem toidentify theratingofa particular firm
Figure2: Distance toDefault
Trang 37Cross Reference to GASP AssignedReading-de Servigny & Renault,Chapter3
Since asset pricesarelognormallydistributed, the DDis morepreciselycalculated using the
followingformulaat timehorizon T%
E(ROA)=expected return on assets
= valueof thefirmassets
= standarddeviationof firmassets
V
Professor'sNote:"log(V)— log(defaultthreshold)" in the equation abovecan
also be written as “log(V1default threshold)."1Also, recall that the valueofthe
firm (i.e., valueofassets) ismade up ofboth debt and equity Therefore, like
the Merton model,oneofthe main driversofthe KMV modelisequity prices
(i.e.,stock prices)
This equation will also beseen inTopic20when we examine theprobabilityofdefaultusing theMerton model Thedifference, however, between MertonandKMVishowthisequationis utilized*Asyouwillsee inthenext topic, theMerton modelcomputes
the cumulative normaldistributionfor the negative value of die previous DD expression.Forexample, if theexpressionequals1,96, theMertonmodelwouldsaythat thereis N(—1.96)= 0.025or 2,5% probabilityofdefault Notethat this valueisfound byusingthecumulative normaldistribution table (i.e., cumulative z-table) in theappendixof this hook
TheKMVmodelon the otherband, usesthesame distance todefaultvalue (e.g.,1.96) and
assessesthe numberofdefaultsat a laterdate(e.g., 1 year) associated with diecomputed
DD value The number ofdefaultsfrom agiven sampleof firms Ls then used to compute
theexpecteddefaultfrequency(EDF).Again, EDF in the KMVmodelisalso known
as theprohahilityofdefault.The EDF will heassociatedwithaparticularcreditrating
(e.g.,BBB),Thefollowingexamplewill helpillustrate thecalculation of expected defaultfrequency
Example:Expected default frequency
Assumethe expectedassetvalueinoneyearfrom theassetvalue distributionis $800, andthedefault thresholdis found tobe $500 Calculatediedistance to defaultif the annual
assetstandarddeviation is 100.
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Trang 38Topic 1 9 Cross Reference to CARP Assigned Reading-de Servigny & Renault, Chapter 3 Answer:
HOO 500
DD=
100
Tocompute EDF, assumethat 2,000firms last year UadaDD of3, and15of these firms
defaultedafteroneyear.The expected default frequency= 15/2,000= 0.75% This value
isassociated with the EDF of thefirmsincethisfirmalso hasaDD of3.An implied
credit ratingis then assigned basedon diis EDFvalue.Forexample,alowEDF,suchas
0.75%,would be assignedanAA-rating
Thecalculationof EDF is avaluableleadingindicatorofdefault andoftentimes predicts
defaultmonthsinadvance.Asharpincreaseinthe slope of the expected default frequencyis
agoodindicator thata creditratingdowngradeislikelyto occur in drenear future,
CREDIT SCORING MODELS
AJM 19.3:Describe credit scoring models and the requisite qualitiesof accuracy,
parsimony, non-triviality,feasibility,transparencyandinterpretability.
Creditscoring models assigna numerical valueto afirm, which indicateswhedierafirmis
likelytodefaultor not.Theirmainfunctionis to assess thecreditworthinessof small and
private firms For example,creditscoresenable small businessestogain approvalfor loansin
ashorteramountoftime.Featuresofoptimalcreditscoringmodelsinclude thefollowing:
• Accuracy-producesalow volumeoferrors.
• Parsimony- uses alimited numberof independent variables
• Non-triviality - producesappealingoutcomes.
• Feasibility— usesaccessible resourcesin a reasonableamountoftime.
* Transparency andInterpretability—dataiseasytofind andinterpret
AJM19.4:Define and differentiate among thefollowing quantitative
methodologiesfor credit analysisandscoring:
+ Lineardiscriminant analysis
Parametricdiscrimination
Knearest neighbor approach
+ Supportvector machines
Fisher linear discriminant analysis.A process thatsegregates alarger groupinto
homogeneous subgroups.Thelargergroupcould bepotential borrowers,for example, and
thesubgroups could begoodand bad borrowers.Anexample of linear discriminant analysis
is Altman’sZscore,
Parametric discrimination.A particularapproach todiscriminantanalysis that uses a
score function to determine die membersof thesubgroups Examplesof parametric
discriminationarelogitand probit models.Parametricdiscriminant analysis determines
Trang 39Topic 19
Cross Reference to GARP AssignedReading-tie Servigny & Renault,Chapter3
a score usinga regression, logit,orother statistical technique.Whether the value of the
scorefalls aboveor belowa certain threshold determineswhich subgroup the observation is
placedin(e.g.,whedierafirm iscategorized into alikely-to-or not-likely-to-default group)
Professor'sNote:Logit modelsare basedonlinearprobabilitymodels, which
restrict the rangeofthedefaultprobability to be between 0andL
©
K-nearest neighbor.A nonparametricdiscriminanttechnique that usesthepropertiesof
firms diat havealreadyfalleninto thecategoriesof Interest (e.g.,defaultor notdefault) and
categorizesa new entrantbyhowcloselyit resembles the membersalreadyineachof the
groups
Supportvectormachines.Amethod that usesthe characteristicsof observations (firms) to create anequation thatdoesdie bestjobofdividingthelarger groupinto twosubgroups.The groupscan belinearandincludeplanesand hyperplanes They can henonlinearwheretheseparationcriteria is apolynomial
AIM19.5:Define and differentiate thefollowingdecision rules:minimumerror,
minimum ris k, Neyman-Pearson andMinimax
Decision rules,asusedincreditanalysis,categorizepatternsof descriptive variables,such
asleverage andearningsmeasures, thatwould then placeailobservation(e.g.,afirm) into a
group(e.g.,ahigh-risk-or alow-risk-of-default group)
Minimum error is adecision rulediatusesBayes’dieorem to determineaprobability
It formsaconditional probabilityofafirmbeingin onegrouporanothergiven its
characteristics,denoted C, anddie highest condidonal probability determines thegroup
towhich thefirm isassigned.Thedecision basically becomesonewhere theuserwould
compute the probabilitiesin thefollowingexpression:
p(Cgivendefault) x p(default) > or < p(C givennotdefault) x p(not default)
If die leftis greaterthan the right, then Cwould indicate that thefirm shouldbe indielikely-to-default group.Iftheinequalityis reversed, then thecharacteristicswouldindicatechat diefirm shouldhein thenot-likely-to-default group
Minimum riskrefersto a classof rules thattry toeitherminimizetheprobabilityof
misclassification (incorrecdylendingto riskyfirm) or minimize the lossassociated widichat error.
Neyman-Pearson is adecisionrulechat uses diestatistical conceptofTypeIandType
IIerrors.AType I error islendingto arisky firm becauseitwasincorrecdy accepted as a
non-ri.skyfirm,ATypeIIerror is notlendingto anon-risky firm becauseit wasincorrectly
rejectedas beingrisky.The procedure first requires that the user select afixed valuefor
the probability ofaType IIerrorandplacesit in aLagrangiau multiplier equation that
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Trang 40Topic 19
Cross Reference to GARP AssignedReading—de Servigny & Renault, Chapter 3
determinesathreshold value For any givensecoffirm “characteristics,13 the decision is to
not extend a loan to the firm if thefollowing holds:
p("conditions'f givendefault)
> thresholdvalue
p("conditions"notgivendefault)
Minimax is adecision ruleof minimizing themaximum error orrisk UsingTypeland
TypeIIerrors asexamples, Lhegoal is m minimizediemaximumof the two.Ina casesuch
asthis where thereareonly two typesoferrors, theminimum isobtained bydetermininga
setofcriteriawhere diecutoffmakes the probabilityof the two typesoferrorsequal toeach
other
In summary, theminimum error rule makesadecision basedoncalculated probabilides
The other three methodsuseoptimization techniques todetermineaclassificationsystem
that reducestheprobability oferrorand/or loss
AJM19.6: Identify theproblemsand tradeoffs between classification and
predictionmodelsofperformance
AIM 19-7:Describeimportantfactorsin the choiceofaparticular classof model
Thereceiveroperatingcharacteristic (ROC)evaluatesacreditdecision ruleby computing
(1) the proportion ofcorrecdypredicteddefaultsand (2) the proportion of firms thatwere
predicted todefaultanddid not:
numberof defaults correcdy predicted
dimensionalgraph.The graphicalrepresentation wouldhavea maximum value ofunity
(i.e., 1) for both the X- and Y-axes TheX-axiscorrespondsto the propertion ofincorrecdy
predicted defaults,andthe Y-axiscorresponds to theproportionof correcdy predicted
defaults Theslopeof the ray from the originto the point represendng the plotof the two
valuesistheperformancemeasure. Ideally, the ray should haveaninfiniteslope;thisoccurs
if alldefaultswerecorrectlypredictedanddierewere noprediedonsofdefaultthat did
not occur Ifthe ray hasa45-degreeslope, then therewereequal proportions oftypesof
mistakes
Thecumulativeaccuracy profile,orGAP (alsocalledGINIcurve),comparesthe
probabilities ofdefaultcomputedby the classificationsystem tothe rankingof observed
defaults.It usesa graphicalsystemsimilartothat of theROC.The vertical axis represents
the fraction of firms that actuallydefaulted,and thehorizontalaxis representsthe
probabilities computed bythe classificationsystem.Theshapeof the lineonthegraph
indicates the successof the classificationsystem.