Revenue Risk, Crop Insurance and Forward...
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RevenueRisk,CropInsuranceandForwardContracting
CoryG.Walters
DepartmentofAgriculturalEconomics,UniversityofKentucky
RichardPreston
PrestonFarms,HardinCountyKentucky
SelectedPaperpreparedforpresentationattheAgricultural&AppliedEconomicsAssociations2013CropInsuranceandtheFarmBillSymposium,Louisville,KY,October89,2013
Copyright2013byWaltersandPreston.Allrightsreserved.Readersmaymakeverbatimcopiesofthisdocumentfornoncommercialpurposesbyanymeans,providedthatthiscopyrightnoticeappearsonallsuchcopies.
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RevenueRisk,CropInsuranceandForwardContracting
Introduction
Overthepasttwentyyears,theUSgovernmenthasdramaticallyenhancedtheFederalCropInsurance
program.Subsidiesandthenumberinsurancecontractswereexpandedthroughboththe1996
AgriculturalReformActandthe2000AgriculturalRiskProtectionAct.Asaresult,insuredacres
increasedfrom100millionto279millionbetween1994and2012(USDARMANational,2012).The
RiskManagementAgency(RMA),whooverseestheFederalCropInsuranceprogram,providesenrolled
producerswithriskmanagementbenefitsthroughamyriadofinsurancecontracts.Withsome
insurancecontractsprovidingmoreriskmanagementbenefitsthanothers.Whatisunclearishow
muchdifferentinsurancecontractsreduceriskandmoreimportantly,riskreductionwhenprivaterisk
managementtools,suchasfuturesmarkets,areusedinconjunctionwithcropinsurance.Theresult
couldpossiblybeincreasedrisktotheproduceriftheydonotunderstandtheimpactofprivatehedging
tools(i.e.,futuresmarkets)onrevenuewhenapublictool(i.e.,cropinsurance)ispresent.
Ofallavailableinsurancecontractchoices,theintroductionofrevenueinsurance,whichadds
priceprotection,createsadirectlinkagewithfuturesmarkets.Thiscontract,calledrevenueprotection,
isthemostpopularrepresenting175millionofthe279millioninsuredacresin2012(USDARMA
National,2012).Enrolledacreageevidencesuggestsproducerprefersincludingfuturespricesinto
theircropinsurancerevenueguarantee.1Producerswitharevenueprotectionmayrespondby
reducing(orevenquitting)participationincommodityfuturesmarketseitherdirectlyorindirectly
throughcashforwardcontractsbecauseinsurancehascoveredthisrisksourceforthem.Thisstudyis
intendedtohelpfarmersunderstandhowrevenueinsuranceandfuturestradingcomplementeach
othertoimprovetheirriskmanagementplan.Weuseaportfolioapproachinmakingriskmanagement1Additionally,participatinginfuturesmarketsviaasubsidizedinsuranceproductmakespriceprotectioncostcheaperthandirectfuturesmarketparticipation.
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decisionsdistributingincomesourcesthroughavarietyoftoolstounderstandtheriskmanagement
linkagesbetweenthesepublicandprivatetools.
Inthispaperweexamineriskfromtheproducerspointofview.Atthebeginningoftheyear
producersarefacedwithuncertainpricesandyields.Producershavetoolsavailabletohelptamethis
uncertainty.Differentfarmershavedifferentobjectivesanddifferentresourcesandarefacedwitha
widerangeofinsurancechoicesandforwardpricingopportunities.Consequencesofdifferentdecisions
areexaminedtohelpindividualproducerscraftriskmanagementplansthatbestsupporttheirindividual
resources,values,andobjectives.Wefocusonthelongtermobjectiveoffarmsurvivalandtheshort
termobjectiveofproducingapositivenetincomeeachyear.Thesearegoalscommontomanyfamily
farmersacrosstheUS.
Weinvestigatetheriskofnotmeetingtheseobjectivesbymodelingpriceexpectationthrough
theuseofcommodityfuturespricesestimatedbythemarketsviewofriskdemonstratedbyusing
pricesofactualoptionstradedviewedwithintheframeworkoftheBlackScolesMertenmodelof
futuresmarketbehaviorandmodelingyieldexpectationbyanalyzinghistoricalfarmyieldsaidedand
constrainedbyexperienceandcommonsense.Futuresmarketsexisttoprovidethebestinformation
onwhatfallpriceswillbeinthespring.Producersareattractedtofuturesmarketsbecausethey
provideaguaranteedpriceinthespringforfalldelivery.Producersareattractedtocropinsurancefor
riskmanagementbenefitsfromyieldandpriceprotection(underarevenueprotectionpolicy)andthe
presenceofthesubsidy.Weuseproducerlevelhistoricalyieldriskadjustedforconsensuslongerterm
risktocapturefarmspecificrisks,risksthatcoulddeviatesubstantiallyfromaggregationtothosebased
oncounty,state,ornationallevelaggregatedata(MillerandKahl,1987).
Futurespricehedgingintroducesanotherrisk.Soldcropmustbeproduced;therefore,crop
yieldriskincreases.Sellingmorecropthanproducedresultsinbuyingbackpresoldfuturespositions.
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Buyingbackpresoldpositionscanbefinanciallyandemotionallypainful.Havingtherightcrop
insurancepolicyinplacecanreducethispainsubstantiallybecauseitreducesyieldrisk.Consequently,
forwardcontractingandcropinsurancecomplementeachother.Butfromtheproducerspointofview
thequestionishowmuchdocropinsuranceandcomplementeachother?Cropinsurancewithharvest
priceprotectionprovidesapartialhedgeforshortfuturespositions.However,theimpactonthe
amountofavailableworkingcapitalwhenanadverseoutcomearisesisnotfullyunderstood.We
developaportfolioapproachthatcandirectlyestimate(withinthelimitsofthemodelanditsdata
input)thelevelofworkingcapitalonhandforfarmsurvival.
Investigatingtherelationshipbetweencropinsuranceandfuturesmarketsonfarmincomerisk
provideschallenges.Areasonableyielddistribution,anapproximatepricedistribution,andthe
dependencebetweenyieldandpricemustbedetermined.Theprimaryissuefacingthemodelerishow
torepresenttheproducersunderlyingjointdistributionbetweenyieldsandpriceswhich
comprehensivelycombinesallthisinformation.Often,thisnegativerelationshipbetweenyieldsand
pricesisreferredtoasthenaturalhedgeandisrelevantindecisionmakingunderuncertainty(Finger,
2012).Farmlocationinfluencesthesizeoftheprice/yieldjointdistribution,makingitdifficulttoidentify
theoptimalcropinsurancecontractandhedgingamount.Additionally,widerangingstatementsabout
whatproducersshoulddobecomesirrelevantiftheprice/yieldjointdistributionisnttakenintoaccount
ormisunderstood.Wedescribetheprice/yielddependencestructurethroughacopula.Wethen
incorporatethecopulaintoaMonteCarlosimulationmodeltoanalyzerevenueriskfacedbyaKentucky
farm.
Anumberofvaluableresultscomeoutofthisstudy.Alloftheresultshelpshedlightonthe
producerscomplexdecisionenvironment.First,weanalyzetailrisk(i.e.,adverseunexpected
outcomes)inprobabilityspace.Second,weincorporateacopulaintothemodeltoaccountforthe
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inversedependencebetweenpriceandyields.Thisisanimportantfeaturebecausethestrengthofthe
dependenceisthefoundationformakingriskmanagementdecisions.Third,thefinancialbenefitsof
combiningcropinsuranceandforwardcontractingcanbeeasilycalculated.Fourth,amountofworking
capitalneededtoensurefarmsurvivalcanbemeasured,in$,throughdifferentcombinationsofcrop
insuranceandforwardcontracts.Thisallowsustocalculatethebenefitsofcropinsuranceduring
adverseoutcomesaloneaswellaswhenforwardcontractsareused.
PriorLiterature
Analyzingpriceriskimpactsproducerrevenueisnotanewendeavor(e.g.HansonandLadd,1991and
Coyle1992).McKinnon,1967foundthathedgingdependsupontheproducersprice/yieldcorrelation.
Whatisrelativelynewisanalyzingimpactsofcropinsuranceandhedgingonfarmrevenue.Dhuyvetter
andKastens(1997)foundthataverageincomewassimilaracrossinsurancetypesbutrevenueinsurance
resultedintheleastincomevariability.Cobleet.al.,(2000)demonstratedthatrevenueinsurancetends
toresultinslightlylowerhedgingdemandwhencomparedtoyieldinsuranceusingthesamecoverage
level.AfollowupstudybyCobleet.al.,(2004),thatintroducedLoanDeficiencyPaymentsintothe
model,foundthatgovernmentprogrammelevelsprofoundlyalterproducersoptionalhedgingstrategy.
Mahul(2003)foundthatrevenueinsurancetendstoresultinlowerdemandforfuturescontracts.
Wanget.al.,(2004)foundthatfutureshedgingisnegativelyaffectedbyrevenueprotection.
Theimportanceofaccountingforyieldandpricedependenceinmeasuringriskisimportant.
Forexample,TejadaandGoodwin,(2008)foundthatforratingrevenueinsurancebyincorporatingthe
price/yieldjointdistribution(viaacopula)resultedinasmallerprobabilityofpayoutthanpresent
methodsbeingused.
Ourextensionofpreviousworkliesinthewayweincorporateproduceravailableinformation
onyieldsandpricesinthefaceofuncertainty.Producersusehistorical,trendadjusted,yieldsasthe
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expectationfornextyearsyield.Theyunderstandyieldvariabilityexistsfromtheironfarmyielddata
andfromresultsoftheirneighborsyields.Manyproducersalsorememberthewidespreadcropfailures
intheearly1980s,andtheirparentsrecollectionofthe50s.Someevenrememberthestoriesofthe
30shandeddownbytheirgrandparents.Thisaccumulatedlocalknowledgehaspushedfarmersto
embraceriskmanagementtoolssuchascropinsuranceandlimitedforwardcontractingtoprotect
revenueagainstadverseimpacts.Forprices,producerslookforwardintime,viafuturesmarkets,
specificallynewcropcontractsforthemostrelevantpriceinformation.Consequentlyweincorporate
historicalyieldrealizationsandforwardlookingnewcropfuturesmarketpricesinassessingrevenue
risk.
ModelingProducerRisk
Traditionallyriskevaluationhasbeenthroughtheexpectedutilityframeworkwhereproducersare
presumedtoberiskaverse,expectedutilitymaximizers(Chavas,2004).Wewritetheexpectedutility
functionas
(1) U E f V ,
whereUisutility,E ,andV isthevarianceofprofit.Thevariancetermrepresentsuncertaintystemmingfromunknownyieldsandunknownprices.Usingthisprofitstructuretheinsuranceselection
andhedgingselectionaffectboth E ,andV .Futureshedgingreducespriceriskbutincreasesyieldrisk.Yieldprotection,aspecificcropinsurancepolicytype,impactsonlyyieldrisk.Revenueprotection,
anotherspecificcropinsurancepolicytype,impactsbothpriceriskandyieldrisk,butnotinasimple
linearadditivefashion.Riskmaybereducedwhenincorporatingbothcropinsuranceandhedging.The
amountofriskprotectiondependsupontherelationshipbetweenactualyieldandprice.
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Insteadofdefiningriskinageneralframework,werankdecisionsbyhowwellandhowlikely
theyhelptheproducermeethis/herspecificobjectives(Clemen,1996).Wedefinespecificrisksasthe
riskofnotmeetingspecificobjectives.Forexample,iftheobjectiveistomaximizeincomethen
decisionsaremeasuredbysimplycalculatingtheexpectedvalueofincome.Iftheproducersobjective
istomaximizeincomewhileminimizinguncertaintyboththemeanandthevarianceofthedistributions
couldbeexaminedtofindthedecisionthatbestsupportsthatobjectiveusingthemaximumexpected
utilityapproachgiveninequation(1).Hereweconcentrateonthespecificriskoffarmsurvivalby
examiningtheshapeoftheincomeprobabilitydistributions.Thisissimilartodevelopingasafetyfirst
setofpreferenceswheredecisionmakerstrytominimizethechanceoffallingbelowagiven
subsistencelevel(Chavas,2004).Farmsurvivalisdownsiderisk.Downsideriskliesinthetailofthe
incomedistribution.Producersdecisionswhichsupporttheobjectiveoffarmsurvivalmakedecisions
tominimizetheirexposuretodownsideriskwhilemaintainingapositiveexpectedincome.
Wemodelvarianceasfarmsurvivalorhavinga1%chanceofanincomeshortfall.Witha1%
chanceoffailure,theproducerthensetsasideXdollarsofworkingcapitaltocoverthe1%incomeat
risklevel.Bysettingbacktheminimumtocoverthe1%probabilityshortfallthereexistsa99%chance
ofsucceedingeachyear.2Wechose1%becauseitisaextremelyrare(1in100year)eventandbecause
workingcapitalneededtocovera1%chancewillcoverotherlowprobabilityevents,suchasthose
comingfrom5%and10%incomeshortfalls.
ConstructingFarmIncomeDistributions
Conceptually,wemodelfarmincomeriskbylookingatthefarmyieldandpricecombinationintheeyes
ofuncertainty.WeconstructaMonteCarlosimulationmodeltoanalyzerisksfacedbyaKYgrainfarm
bycalculatingadistributionofincomeoutcomesgivenreasonableinputdistributionsforpricesand
2Assumingindependentweatherthechanceofsuccesstosurviveeachyearbecomes.99^n.Forn=20yearstheproducerwhoworriesaboutprotecting1%incomeshortfallhasan82%chanceofsuccess.
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yieldscombinedwithanestimateoftheprice/yieldcoupling.Riskcanbemeasuredbystudyingthe
shapeoftheresultingincomedistributions.
Peracreprofit,withoutinsuranceorhedging,isgivenby
(2) p y c z y
Whereprepresentsoutputprice,yisactualyield,cisthefixedcostofproduction,andthefunctionz y representstheperbushelharvestcost.PurchasinginsuranceaddsthetermI r, r , z u z toequation(2),whereI . representstheinsuranceindemnityorpaymentfromtheinsurancecompanytotheproducer,rrepresentsactualrevenue(y p , wherep representstheinsuranceharvestprice;r isguaranteedrevenue,calculatedas y p CL ,wherey representsthe
yieldguarantee,p representstheinsurancebasepriceandCLrepresentsthepercentinsured.3Hedging,throughtheuseoffuturesmarkets,addsthetermp y ,wherep representsthehedgedproductionpriceandy representsthenumberofbushelshedged.Includinghedgingreducesthenumberofbushelstobesoldatharvest,therefore,wereplaceyieldinequation(2)withy whichistheremainderofy y .Withunknownyields,itispossiblefory tobegreaterthany.Whengiventheoptionofpurchasinginsuranceandhedgingtheproducersprofitperacreis
(3) p y y c z y I r, r , z u z p y
Afterthefinalyieldandpricearerealized,itwouldbeeasytoplugthevaluesintoequation(3)
anddeterminewhichdecisionchoicemaximizesincome.Ofcourse,insurancecontractselectionand
forwardcontractingdecisionsmustbemadebeforep and yareknown.Inthespring,bothp and y areuncertain.Itisusefultothinkofp and yasrandomvariableswithonlytheirjointprobability,,P( , ,knowninMarch.Thejointprobability, P( , ,measuresthechancethataparticular(pi,yi)3Underarevenueprotectionpolicy intherevenueguaranteecalculationcouldbereplacedwith if
.Forayieldprotectionpolicy isreplacedwith intheactualrevenuecalculation.
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combinationwilloccurinDecember.Associatedwitheach(pi,yi)pairandjthdecisionisanincomei,jgeneratedbyequation(2).
WecanuseaMonteCarloapproachtoobtainanestimateoftheincomeprobability
distribution.MonteCarlomethodsarerootedinthesimilaritybetweenprobabilityandvolume
(Glasserman,2004).4OnceweknowthejointprobabilityweconductaMonteCarlosimulationby
randomlychoosingpandymanytimesinafashionthatreproducestheshapeofP( , byinsuringeach Psegmenthasanequalchanceofbeingvisited(Vose,2008).Equation(3)mapseachpair
ofp, yintoanincome.Thedistribution(volume)ofincomesproducedreflectstheprobabilityofthatincomeoccurring.Risktodifferentobjectivescanbestudiedbyexaminingtheshapeoftheoutcome
volume.Eachchoiceisgoingtoproduceadifferentshapefortheincomedistribution.Theincome
resultsarecollectedinavectorofoutcomeswitheachdecisionlabelingadifferentcomponent.
ModelingtheDistributions
Thefirststepistoconstructthejointprobabilitydistribution,P( , ).Wedividetheproblemintobuildingamarginaldistributionforyield,y,constructinganestimateforthemarginaldistributionfor
price,p,anddevelopinganalgorithmtomodelthedependencebetweenyandp.
YieldDistributions
4Thinkofasimpleonevariablehistogram.Theprobabilityofaparticulareventoccurringisrelatedtothearea,whichrepresentsvolumein2D,occupiedbythecorrespondinghistogramdividedbythetotalareaofallpossibleevents.Thiscanbeextendedtohigherdimensions.AthreedimensionalhistogramrepresentationofP( , could be constructed by tossing all events that fall between pi and pi+1 and yi and yi+1 into a bin labeled P( , IwiththeheightofP( , IgivenbythenumberofeventswhicharecollectedinP( , I.NormalizingthevolumeofP( , Ibydividingthenumberofeventslandingineachbinbythetotalnumberofeventsturnsthevolumeintoajointprobability, P( , .
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Itisdifficulttogetalongenoughtimeseriesoffarmlevelyielddatathatadequatelydescribesfarm
yieldrisk.Asaresultresearchersoftenusecountyleveldatatodescribefarmyieldvariation.
Aggregationtothecountylevelcouldaverageoutpoororexcellentoutcomes.Inthisstudy,todescribe
farmlevelyieldvariabilityweuseyearlyfarmaverageyieldforasingleproducer.Thisproducerhas
beeninbusinesssince1979.
Sincethefarmstartedproducingin1979through2011yieldsincreasedsteadily.Todetermine
theamountofyieldriskwefirstremovetheyieldtrend.Failuretoremovethetrendwillresultinan
overestimateoffarmyieldrisk.Tocalculatethetrend,weregresscurrentyieldonthepreviousyield
usingLinearLeastSquaresusinghistoricalfarmdatafrom1979to2011.Theresidualratiodistribution,
Rf,whichweuseasthesamplingdistribution,iscalculatedas
(4) Rf
whereY representsyieldattimet,YT representstheestimatedyieldtrendattimet,andRfrepresentstheresidualratio.Wecanexpresstheunknown,nextyearsyieldas
(5) Rf
WeassumeRfcanbeusedasastationarysamplingdistribution,i.e.,thatthedistributionofratiosof
differencefromthetrenddividedbythetrenddonotchangeovertime.
The33yearsofyielddataareasampledrawnfromapopulationdistributionwhichisassumed
toexist.Figure(1)showstheRcdistributions,forHardincountyKY,Rfshowsthehistogramsforthe
farmunderstudy,RsandRnshowthehistogramsforthestateandnationallevels,respectively.The
normaldistributionhasshowndoesapoorjobofrepresentingyielddataashasbeenreportedby
severalauthors(Hennessy,2009;Sherricketal.,2004;Atwood,Shaik,andWatts,2002).Boththefarm
andcountydistributionsareskewedtotheleftsuggestingthatanormaldistributionwouldunder
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estimatetheprobabilityoflowyieldevents.Effortstofitthefarmdatatoseveralcommonfunctional
formsproposedintheliteratureincludingtheBetafunctionandWeibullfunctionfailedtoadequately
representthelowyieldtail(Sherricketal.,2004).WewantourRfdistributiontoadequatelydescribe
thechanceofanymajoryieldimpactingevent;therefore,wedevelopanempiricaldistributionby
plottingthecumulativedistributionanddrawingasmoothlinethroughthepointswiththeadditional
constraintthatthelinemustpassthroughapointwith1/30probabilitythattheyieldwillbeatleastas
badasitwasin1983.Thisconstraintwasaddedtomodeltheextremelowyieldeventswhichhave
occurredinthe30s,50s,and80swhichisaboutonceevery30years.Thisconstraintleadstoafatlow
yieldtail.ThisfattailbehaviorwaspredictedbeforethemajorKentuckydroughteventof2012.The
majoryieldshortfallwhichoccurredin2012iseasilyexplainedwithinthemodelforRfproposedforthis
farm.
PriceDistributions
WeareinterestedinthechangeinDecemberfuturespricefromMarch1toDecember1.Webuildan
approximatelystationarysamplingdistributionbytakingtheLnoftheDecemberfuturespriceon1
dividedbytheDecemberfuturespriceonMarch1andwedesignatethisdistributionasLnPh.
AssumingthedataresultedfromsamplingofaLogNormalpricedistribution,wecanusethisdatasetto
estimatetheparametersofLnPhwhichleadstoanestimateofaLogNormalhistoricaldistributionof
prices.Inthenextsectionweinvestigatethecouplingbetweenourpricesamplingdistribution,LnPh ,
andouryieldsamplingdistribution,Rf.
Insteadofusing LnPh directlyasasamplingdistribution,wechosetousethenewcropfutures
contractmarketinformationonMarch1toproduceaforwardlookingdistributiontoaccountforthe
possibleincreaseordecreaseinpricevolatility.Optionmarketpriceswereusedtoestimatetheprice
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probabilitydistribution.5Ourgoalistofocusonpricechange,butweconstructLnPbbyusingaBlack
ScholesMertonstochasticmodeltorelateastartingpointonMarch1toadistributiononDecember1.
Inordertodeterminethepriceprobabilitydistributionwefirstcalculatetheimpliedvolatility.
Weusedtheaverageofpremiumspaidfortheatthemoneycallandtheatthemoneyputfornew
cropfuturescontractoptionpricesandtheoneyearLIBORratetoestimateimpliedvolatilityusing
DerivaGemsoftware(Hull,2012).ThisimpliedvolatilitywasusedinBlacksmodelforvaluingoption
contractsatexpiration(Hull,2012).BlacksmodelassumesthatEuropeanoptionscanbeusedtomodel
Americanstyleoptions.6Blacksmodelprovidesalognormalpriceprobabilitydistribution.We
estimatethepriceprobabilitydistributioninthespringonMarch1st,justafterthecropinsurancebase
wasset.7Decembercornoptionpricesexpireapproximatelyoneweekbeforefuturescontractsenter
thedeliveryperiod.
JointdependenceandCopulas
Webaseouranalysisoffarmincomeriskonthejointdistributionbetweenyieldsandprices.Yieldsand
pricesarerelatedthroughsupply,loweryieldsreducesupplywhichholdingeverythingelseconstant
wouldresultinhigherprices.Thestrengthoftheinversepriceyieldrelationshipdependsupon
producerlocationrelativetotheprimarycropgrowingarea.8Forexample,becauseIowaistheprimary
corngrowingstate,averylargedeclineforanIowaproducersfarmyieldwouldlikelybeassociatedwith
lesscornmarketsupply,which,holdingeverythingelseconstant,wouldpushcornpriceshigher.As
producerlocationincreasesawayfromtheprimarycorngrowingareatheinversepriceyield
5Foradiscussionofprobabilitypricedistributionsusingthisapproachseehttps://www.msu.edu/~hilker/crnfut.htm6Europeanstyleoptions,oncepurchased,mustbehelduntilexpirationvs.Americanstyleoptionsthatcanbecontinuouslytradedanytimebeforeexpiration.7ForcorninKentuckythespringbasepriceistheaverageofDecembercornfuturesmarketduringthemonthofFebruary.8Irrigationwouldalsoplayarolebutisnotincludedinthisanalysis.
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relationshipwouldweakenorpossiblydisappear.CornyieldsinWashingtonStatewouldhavelittleto
noimpactoncornfuturespricessinceWashingtonStateissofarremovedfromtheprimarycorn
growingregion.9Duetothepresenceofaninversepriceyieldrelationshipitisimportanttomodelthis
asajointdistributionthroughtheuseofcopulas.Copulasallowstwofunctions,whowethinkare
related,tobetiedtogether.Copulasarearelativelynewmethodinansweringriskmanagement
questions(Embrechs(2002),Embrechs(2003),Kole(2007),Goodwin(2012)).Animportantfactorwhen
usingcopulasisthecopulaselection.Koleetal.(2007)foundthatriskswereoverorunderstated
dependinguponthetypeofcopulaused.
CopulasarethecombinationofmultiplejointdensitiesintoonejointdistributionthroughSklars
theorem(Sklar,1973).Thecopuladescribesthedependencebetweentherandomvariablesthrough
mappingfromtheindividualdistributionfunctionstothejointdistributionfunction
(6) F x , , x C F x , . , F x
wherex , , x representsanhcontinuousrandomvariableswithacumulativedistributionfunctionF x , , x ,marginaldistributionfunctionsofF x , . , F x andcopulafunctionC.10
Forourmodelweareconcernedidentifyingacopuladisplayingtaildependence.TheClayton
copula,fromtheArchimedeancopulafamily,displaystaildependence.TheClaytoncopulatakesthe
form
(7) C x , x , x x 1 /
where,thedependenceparameter,isrestrictedtobegreaterthanzero.Archimedeancopulashavethespecialpropertythatallowsthemtobeconstructedfromagenerator,,(Nelson)
9Itwouldlikelyimpactregionalcornbasis.10ForathoroughbackgroundoncopulamodelingseeTrivediandZimmer(2005).
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(8) , [1](( 2))
withtheClaytongenerator(Nelson,2006)givenby
(9)(t)=(1/)(t1)
Asapproacheszerothemarginaldistributionsbecomeindependent.Asincreasesinsizethemarginaldistributionsbecomemoredependent.TheClaytoncopulawith>0accountsforpositivedependence,notnegativedependenceandourhistoricaldatasuggestsverystrongnegative
dependence;lowyieldsimplyamuchstrongchanceforhigherprices.FortheClaytoncopulatowork
withnegativedependencewetransformthedataintopositivedependencebychangingthesampling
distributionforpricesfromLnPbpriceratioto1 LnPbpriceratio.Thehistoricaldataforthisfarmdoes
notsuggestthathighyieldsimplyastrongchanceoflowerprices.WefoundthattheClaytoncopula
exhibitsthistypeofrelationship;strongtaildependenceononesideofthedistributionandweak
dependenceontheotherside.
AnArchimedeancopulacanberelatedtoKendalltau,,whichisaglobalmeasureof
dependencebetweentworandomvariables(MariandKotz,2001)by
(10)=14 01(/')
UsingthegeneratorfortheClaytoncopula(Nelson,2006andVose,2008)relatestheparameter,,to
asshowninequation(11)
(11)=2/(1)
Weestimateusingequation(11)andhistoricalfarmyieldsandpricestocalculateKendaltaubetweenRfand1 LnPb..
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TorunthefinalMonteCarlomodelseveralstepsweretakentoincorporatetheCopula.The
firstissueisgivenanyx howtogetthecorresponding x .WeusetheLaplacetransformmethodbecauseitisstraightforwardwiththeClaytoncopulasinceitsgeneratoristheinverseLaplacetransform
oftheGammafunctionwitharguments1/and1(Nelson,2006)andcomputationallyefficient
(Chrisman,2013).With x , x )pairswethenfindyieldsandpricesbytakingtheinverseoftheirrespectiveCDF.Because1 LnPbwasassumedtohaveanormaldistributionwetaketheinverseofthe
normaldistributionusingthelibraryroutineprovidedbyANALYTICAdecisionsoftware(LuminaDecision
Software,2013).Thesamplingdistribution, Rf,connectedtoyieldisempirical.Atwodimensionalarray
withdimensions(30000,2)isbuiltcontainingx inonecolumnandCDFarrayforRfintheother.Becausex andtheCDFsdomainsare[0,1]andtheCDFisaincreasingfunctionon[0,1]theinversecanbenumericallyestimatedbyusingatablelookupmethod.WeusealibraryroutineinAnalyticawhich
usescubicspinestointerpolatebetweentheelementsofthearray.
Model
ToanalyzerevenueriskmodelwerunaMonteCarloprobabilitysimulationwith30,000iterations.
MonteCarloprobabilitysimulationallowstheprobabilitycalculationof,farmrevenue.Fromthiswecan
assessthelevelofincomeriskandimpactfromriskmanagementtools(cropinsuranceandfutures
hedging).RiskmanagementvariablesincludedwereCropinsurance(noinsuranceandrevenue
protection,RP,andrevenueprotectionwithharvestpriceexclusion,RPHPE,atdifferentcoverage
levels),hedging(futuresmarket,nohedgingto110%ofexpectedproductionhedgedin10%
increments).Forcropinsuranceunitchoicewelimitouranalysistoonlyenterpriseunitsbecausethe
produceristryingtomanagefarmincomeandfieldsenteringandexitingproductionovertimemakesit
difficulttoobtainfieldlevelyieldprobabilitydistributions.Welimithedgingtothefuturesmarketviaa
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hedgingaccountatabrokeragefirm.Theproduceriscompletelyresponsibleformarginpayments.11
GrainistobevaluedonDecember1atharvestusingthehistoricalbasisonDecember1.Historicalbasis
isestimatedastheaverageoverthe20yearsattheelevatortheproducertraditionallydeliversto.We
useANALYTICA,decisionsupportsoftwarespecializinginriskanalysisusingMonteCarlomethods,to
analyzeourincomeriskmodel.
Farmproductioncostsarecalculatedintwocomponents,coststhatareindependentofyield
andcostsdependentuponyield.Thiscalculationmethodaccuratelyreflectsfarmercosts.Giventhe
samecropinsuranceyieldguaranteeontwofieldstheproducerwouldbefinanciallybetteroffwitha
zeroyieldvs.ayieldonebushelbelowtheguarantee.12Itemsusedtocalculatecostsarethesameas
thosefoundinaLandGrantUniversityextensionbudget.Forcostsdependentuponyield,thosewere
estimatedusinghistoricalperacreharvestcosts.Costsincludedwouldbe:combinecosts,truckingcosts
(bothfromthefieldtobinandbintoelevator),anddryingcosts.Thecostperacreincludinglandcosts
wasassigned$606forthisfarmwhiletheestimatedperbushelyieldis%0.58.Theaverageyieldis143
bu/acreleadingtoatotalcostof$689peracre.Thisaveragetotalcostperacreissimilartotheaverage
costsfoundintheUniversityofKentuckynotillcornbudgets(Halich,2012).
Weanalyzefarmrevenueportfolioattwodistinctpointsintime.Thefirstpointisin
thespring,rightafterthecropinsurancebasepriceisdetermined.Thisalsocorrespondstothetime
whentheproducerismakinginvestmentdecisionsonwhichcroporhowmuchcroptoplant.The
secondpointisinthefall,justbeforeDecemberfuturesgointodelivery.Harvestiscompletedsocrop
sizehasbeendeterminedaswellascropinsuranceharvestprice.Forsimplicitythecropinsurance
11Herewedonotincludetheriskproducedbydaytodaymarginfluctuations.Insteadinthespiritofzerodrift(theperfectmarketassumption)wechargethecommissionplustheinterestontheinitialmarginrequirementincurredfromMarch1toDecember1.Marginriskisveryreal.Themodelhasbeenexpandedtoincludetheoptionofusingoverthecounterderivativessuchashedgetoarriveorcashcontracts.Weusuallypresentresultstofarmersusingthesemorespecificderivativesinordernottobeseenasencouragingriskybehavior.12Thisonlyappliestothecurrentyear.Thefollowingyearsyieldguaranteewouldbelowerforthezeroyieldproducerthantheonebushelbelowyieldguaranteeproducer.
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harvestpriceissetequaltofuturespriceonDecember1.13Thesepointsintimeareimportantbecause
oftherelationshiptospringplantinginvestmentsandhowcropinsurancefunctionstoprotectprices.
Forhedginginthisfirstordermodel,cropcanonlybepresoldatthefirstpoint(March1)inthespring.
Anyremainingunsoldbushelsmustbesoldatthesecondpoint(December1)andoversoldbushelsare
boughtbackatthesecondpoint.WedonotconsiderstoragepastDecember1becauseitisoutside
thecropinsurancepriceprotectionwindow.Anyincomeorlossincurredbystoringunpricedcroppast
December1canbecreditedtoaseparatestorageenterpriseandestimatedusingadifferentmodel;
therefore,postharvestpricedecisionareseparatedfrompreharvestdecisions.
Ourdataislimitedtooneproducerwith33yearsofexperience.Withonlyoneproducerovera
relativelyshorttimeframeourresultscouldleadtoaninaccurateassessmentoflinkagesbetweencrop
insuranceandhedging.Specifically,ourproducercouldhaveyieldriskthatisnotrepresentativeof
eitherthecountyorstateyieldrisk.Asaresultwecalculateyieldriskatthefarm(ourproducer),
county,stateandnationalleveloverthesamedataperiodasourproducer.Figure1presentsthese
histograms.14Itisthedistancebelowzeroonthexaxisthatisimportant.Aggregationfromthefarmto
thecountydoesnotchangethelevelofyieldrisk.However,aggregationfromthefarmtothestateor
evennationallevelreducestheamountofyieldrisk.Consequently,onewouldexpectsimilarresults
fromfarmorcountyanalysisbutnotfromthestateornationallevel.
Results
13ThefallpriceguaranteeforKYistheDecemberfuturesaveragedoverthemonthofOct.UndertheBlackScholesMertonassumptionsofastochasticprocessfollowinggeometricBrownianmotionthisisapathdependentquantity(Glassman,2004).Wehavemodeledthisquantityanditsdistributionhasaslightlysmallerspreadandthesameaverage(zerodrift)astheDecember1futurespricedistribution.HarvestpriceprotectionisnotaperfecthedgeforafuturespositionliftedonDecember1;however,wefeelthisapproximationwillnotsignificantlyalterourresults.14FfCnrepresentsthefarmyieldhistogram,CtCnrepresentsthecountyyieldhistogram,StCnrepresentsthestateyieldhistogram,andNtCnrepresentsthenationalyieldhistogram.
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December2013cornfuturespricesCumulativeDistributionFunction(CDF),whichwasanalyzedon
March1,2012becausethatisthefirstdayafterthecropinsurancebasepricewasset,ispresentedin
figure2.AccordingtooptionpricesandBlacksoptionspricingmodelthereexistsatenpercentchance
offuturespricesoflessthan$4.00perbushelatexpiration.Therealsoexistsatenpercentchanceof
futurespricebeinggreaterthan$7.55perbushelatexpiration.Themedianpriceis$5.60perbushel.
Thehistorical,detrendedcornfarmyieldCDFispresentedinfigure3.Accordingtohistorical
yields,thereexistsatenpercentchancethatyieldscouldbebelow100bushelsperacreandaten
percentchanceofyieldsbeingabove170bushelsperacre.Themedianyieldis155bushelsperacre.
Farmcornyieldriskdisplaysstrongtailriskinthatthereexistsamuchbetterchanceoflowyieldsthan
highyields.
Incomerisk,inprobabilityspace,facedbytheproducerwithandwithoutcropinsurancepolicy
(Revenueprotection,enterpriseunits,80%coveragelevelpolicy)arepresentedinfigure4.Large
differencesinincomeriskexistwhencropinsuranceispresent.Forexample,atthetenpercent
cumulativeprobabilitylevel(ora1in10event)thereexistsaapproximatelya$100peracrerevenue
increasewhencropinsurancecontractispurchased.Thedifferenceinrevenuebetweennocrop
insuranceandcropinsuranceincreases(decreases)asthecumulativeprobabilityleveldecreaes
(increaes).Bothpathscrosszeroincomeatapproximatelythesamepoint.Aresultindicating,forthis
producer,cropinsurancedoesnotenhanceincomeitmakeslossessmaller.Thechanceoflosingmoney
isapproximately25%.Asincomebecomesmorepositivethenoinsurancepathresultsinmoreincome,
withthedifferencebeingthepremium.
Includinghedging(50%expectedproductionhedged)intotheincomeriskmodelindicatesa
furtherreductionintailrisk(seeFigure5).Atthe10percentriskcumulativeprobabilitylevelthere
existsapproximatelya$130peracrerevenueincreasewhencropinsuranceispurchasedwithhedging
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vs.hedgingalone.Moreimportantly,atthe10percentcumulativeprobabilityarea,includinghedging
withcropinsuranceprovidespositiveincomeofabout$30peracre.Hedginglowersriskoflosing
money.Withouthedgingtherewasabouta25%oflosingmoney(seefigure3).Withhedgingthe
chanceoflosingmoneydropsto17percentforthenoinsurancepathanddropsanastonishingamount
to4%whencropinsuranceisused.Noinsurancepathcrossestheinsurancepathatapproximately31%
cumulativeprobabilitylevel;abovethisthereexistssmalldifferencesinbothpaths.
Figure6presentsreductionsinincomeriskfromdifferentcoveragelevelswith50%hedging.
60%coveragelevelprovidesthemostincomeriskwhile85%coveragelevelprovidestheleast.At70%
cumulativeprobabilitylevelresultsareopposite;60%coveragelevelprovidesthemostrevenueand
85%providestheleast.Differencesareequaltopremiumamounts.
Figure7providestheefficientfrontierofdifferentportfolios.Fromtable7wecanidentifythe
setofoptimalportfoliosorportfoliosthatmaximizereturnrelativetoanacceptablerisklevel.
Portfolioswiththehighestexpectedreturnandlowesttailriskrepresenttheefficientfrontier.What
standsoutintable7isthatnopointsfromthenoinsurancepathexistontheefficientfrontierandat
allhedginglevelsriskincreasesovernohedging.Hedging,whennoinsuranceispresent,increasesthe
riskofnotmeetingthefarmsurvivalobjective(1%tailrisk).Hedgingreducesvariability,butitincreases
tailriskbecauseeachcontractedbushelnotraisedmustbeboughtbackifthefallpriceishigherthan
thecontractprice(Hedgingstarchesthetailsevenasitreducesthevariance).Negativecorrelation
betweenfarmyieldandfallpricemakesthisworse.Shapesofyieldandpricedistributionsdetermine
thisoutcome.
BothRPandRPHPEinsurancepolicytypesexistontheefficientfrontier.However,onlyoneRP
HPEpointexistsandthatiswithnohedging.RPandRPHPEwithnohedgingprovidethehighest
expectedreturnwithanimprovementinriskatthe1%levelofjustover$292peracreoverno
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insurance.AshedgingincreasespastzeropercenttheefficientfrontierexitsonlyontheRPpath.15At
the1%probabilitylevelrevenueriskisminimizedwithRPbetween3040%ofexpectedyieldhedged.
Hedgingat30to40%ofexpectedyield,underaRPinsurancepolicy(othercontractelementsare80%
coveragelevelandenterpriseunits),reduced1%revenueriskbyanadditional$39peracre.After55%
hedgedrevenueriskincreasedsteadily.Thehighestrevenueriskwithinsuranceandhedging,at120%,
wasconsiderablylowerthannoinsuranceandnohedging.
ForRPonlythereisevidenceofnearlyidenticalrisklevelsusingdifferenthedginglevels,Figure
7.Forexample,10and70percenthedgingprovides41to44dollarsperacreofrevenuerisk,
respectively.Whilebothhedginglevelsprovidethesamerisk,expectedincomeatthe70percent
hedginglevelisnearly$14.00peracrelessthanthatfoundatthe10percenthedginglevel.Recallthat
theproducerselected80%coveragelevel.Evidencesuggeststhathavingahighcoverageleveldoesnot
implyhedgingtothatcoveragelevelforoptimalrisk/reward.Inourcase,hedgingtolevelssimilartothe
selectedcoverageisnotontheefficientfrontier,expectedincomecanbeimprovedwhileholdingrisk
constant.
Reportedinfigure8,theaverageincomefromcropinsurancewashigherthanwithout
insuranceacrossallhedginglevels.Aresultindicatingthatovertime,30,000yearsinourcase,crop
insuranceindemnitieswillbelargerthanproducerpaidpremiums.Thedifferenceistheamountofthe
subsidy.Cropinsuranceissetuptobeactuariallyfair,meaningthatovertimeindemnitiesequal
premiums.However,producersdonotpaytheentirepremium,justaportionofit.Asaresult,over
time,producerswillgetmoremoneyinindemnitiesthanpaidinpremiums.
Ourfindingssuggestthatarevenueprotectioncropinsuranceplanincombinationwithforward
contractingminimizesrevenuerisk.TheyarecountertofindingspreviouslynotedbyCoble(2000)and
15RPHPEincreasesinrevenueriskpastthe10percenthedginglevelbecauseyieldriskisgreaterthanthereductioninpricerisk.
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Wang(2004)thatcropinsurancenegativelyimpactstheneedforforwardcontracting.However,our
resultsaresensitivetobothfuturespriceriskandalsoproduceryieldrisk.Twovariablesthatwhen
changedcouldleadtodifferentconclusions.
Conclusions
Inthispaper,weinvestigatedrevenueriskimpactsfromcropinsuranceandforwardcontractingfora
producergrowingcorn.Ourfindingscontributetothevalueofinsurancetotheproducerand
demonstratetheimportanceofcropinsurancewhenhedgingispresent.Thisarticlecanaidinthe
debateoftheimportanceofcropinsurance.
Revenueriskimpactsfromcropinsuranceandforwardcontractingwereanalyzedusinga
portfolioapproachontwodays,oneinthespringjustafterthecropinsurancebasepricewassetand
theotherinthefallrightbeforeDecemberfuturesgointothedeliveryperiod.Weanalyzehow
differentcropinsurancecoveragelevelsandhedginglevelsimpactrevenuerisk.Understandingthe
revenuerisklinkagesbetweencropinsuranceandhedgingwouldresultinproducersmakingbetter
informeddecisionsandpolicymakersbetterunderstandingofthevalueofcropinsurance.Whilecrop
insuranceimprovesriskmanagementoverdoingnothingthecombinationofcropinsuranceand
hedgingprovidesfurtherriskreduction.Themagnitudeofriskprotectionbenefitswasquitelarge.The
costsofriskmanagementforfinanciallybeneficialoutcomesarequitesmall.
Justpurchasingcropinsurance,withouthedging,providesaexceptionallylargedecreasein1%
tailrisk.Forourproducer,thereisa$292.2peracrereductionintailrisk.Asaresult,theproducer
canreleasethesedollarsfromworkingcapitalandapplythemtootherinvestments,makingthefarm
moreefficient.Thischangeinworkingcapitalonhandforadverseeventshasapositiveimpactonthe
farmeconomybecausethesedollarswouldbeinvested.While1%riskwasreducedfromjust
purchasinginsurancewithouthedgingexpectedincomerose.Forourproducer,purchasinginsurance
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increasedexpectedincomeby$23.7peracre.Withpurchasinganinsuranceproductonewouldexpect
areductioninexpectedincome;however,wefindanincreaseinexpectedincome.Theanswertowhy
isclearthepresenceofthepremiumsubsidy.Producerspayaportionoftheactuariallyfairinsurance,
therebyovertime,allowingthemtogainbackmoreinindemnitythantheiroutofpocketcosts.
Resultsindicateexceptionallylargerevenueriskreductionatthe1%risklevelwhencrop
insuranceispresentandfutureshedgingwitharevenueprotectionpolicy.Ourresultsarespecificand
requirecautionwheninterpretingresults.First,resultsarespecificto2013cropinsurancebasepriceor
springfuturesprices.Changesinthesepriceswoulddirectlyimpactlevelofrevenueriskprotectionsoit
isimpossibletoinferlongtermresults.Second,resultsarespecifictofuturespricevolatility.Changesin
volatilitywoulddirectlyimpactthelevelofhedging.Third,weanalyzeonlyonecrop,corn,different
cropswouldundoubtedlyleadtodifferentrevenueriskimpacts.Fourth,wedonotidentifystatistically
significantdifferencesindifferentportfolios.Especiallycrucialwhentherearesmallchangesinriskat
differenthedginglevels.Fifth,ourmodeldoesnotallowgrainstorageoranyothertypeofhedging
tools(i.e.,hedgetoarrivecontractsoroptions).Slightimprovementintheresultsisexpectedusing
thesetools.Likelythelargestgainwouldbeinsavinginterestexpenseonmarginpaymentsbyusing
hedgetoarrivecontractsvs.futurescontractsdirectly.
Oneparticularlyinterestingresultisthatofhedgingwithoutinsurance.Resultsindicatethatrisk
increasesatalllevelsofhedging.Hedgingunderourobjectiveoffarmsurvival,the1%revenuerisklevel
inourcase,increasestailriskbecauseeachcontractedbushelmustbeboughtbackifthefallpriceis
higherthanthecontractprice.Negativecorrelationbetweenfarmyieldandfallpricemakesthisworse.
Thecombinationofexperiencinglowyields,higherpricesandhedgingcommitmentsistheworst
scenariofortheuninsuredproducer.Becauseourmodelanalyzestwopointsintime,onceinthe
springandtheotherinthefall,itcannotallowforbuyingbackhedgedbushels,atthelowestpossible
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price,oncethereisastrongchancethatcontractedbushelswillnotbemet.Additionally,theproducer
couldrollundeliverablecontractedbushelsintothenextcropyear,afeatureourmodeldoesnot
allowfor.Itispossiblethatourmodelcontainstheworstcasefinancialscenarioofnotmeetinghedged
bushels.Lessfinancialoutcomesexistandwouldlikelybeexercised.
Resultsleadtoadditionalresearchquestions.Forinstance,revenueriskimpactsfromdifferent
cropsandregions.Furtherinvestigationintotheimpactofthenaturalhedgeonrevenueriskreduction
andoptimallevelsofhedgingwouldbeusefulforbothproducersandpolicymakers.
Acknowledgments
TheauthorsaregratefultoJerrySkeesforhelpfulmodelingsuggestions.
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References
Atwood,J.,Shaik,S.,&Watts,M.2003.Arecropyieldsnormallydistributed?Areexamination.AmericanJournalofAgriculturalEconomics,85(4),888901.
Chavas,J.2004.RiskAnalysisinTheoryandPractice.ElsevierInc.
Chrisman,L.ChiefTechnologyOfficer,LuminaDecisionSystems.Privatecommunication.
Clemen,R.,T.1996.MakingHardDecisions:AnIntroductiontoDecisionAnalysis(2nded.).DuxburyPress.
Coble,K.H.,Heifner,R.G.,&Zuniga,M.2000.Implicationsofcropyieldandrevenueinsuranceforproducerhedging.JournalofAgriculturalandResourceEconomics,432452.
Coble,K.H.,Miller,J.C.,Zuniga,M.,&Heifner,R.(2004).Thejointeffectofgovernmentcropinsuranceandloanprogrammesonthedemandforfutureshedging.EuropeanReviewofAgriculturalEconomics,31(3),309330.
Coyle,B.(1992).RiskAversionandPriceRiskinDualityModelsofProduction:ALinearMeanVarianceApproach.AmericanJournalofAgriculturalEconomics74:849859.
Dhuyvetter,K.C.,andT.L.Kastens.1997.CropInsuranceandForwardPricingLinckages:EffectsonMeanIncomeandVariance.ProceedingsoftheNCR134ConferenceonAppliedCommodityPriceAnalysis,Forecasting,andMarketRiskManagement.Chicago,IL.[http://www.farmdoc.uiuc.edu/nccc134].
Embrechts,P.,McNeil,A.,&Straumann,D.2002.Correlationanddependenceinriskmanagement:propertiesandpitfalls.Riskmanagement:valueatriskandbeyond,176223
Embrechts,P.,Lindskog,F.,&McNeil,A.2003.Modellingdependencewithcopulasandapplicationstoriskmanagement.Handbookofheavytaileddistributionsinfinance,8(1),329384.
Finger,R.2012.Howstrongisthenaturalhedge?Theeffectsofcropacreageandaggregationlevels.In123rdSeminar,February2324,2012,Dublin,Ireland(No.122538).EuropeanAssociationofAgriculturalEconomists.
Glasserman,P.2004.MonteCarloMethodsinFinancialEngineering.SpringerCo.
Goodwin,Barry.2012.CopulaBasedModelsofSystemicRiskinU.S.Agriculture:ImplicationsforCropInsuranceandReinsuranceContractsUnpublishedURL:http://rmi.gsu.edu/research/downloads/2012/Goodwin_SystemicRisk_Update.pdf
-
24
HalichG.2012.CornandSoybeanBudgets(CentralKY2012).Retrievedspring2012fromhttp://www2.ca.uky.edu/agecon/index.php?p=110
Hanson,S.D.,Ladd,G.W.,&Curtiss,C.F.1991.Robustnessofthemeanvariancemodelwithtruncatedprobabilitydistributions.AmericanJournalofAgriculturalEconomics,73(2),436445.
Hennessy,D.A.2009.Cropyieldskewnessandthenormaldistribution.JournalofAgriculturalandResourceEconomics,3452.
Hull,J.,C.2012.Options,Futures,andOtherDerivatives(8thed.).PrenticeHall.
Kole,E.,Koedijk,K.,&Verbeek,M.2007.Selectingcopulasforriskmanagement.JournalofBanking&Finance,31(8),24052423.
LuminaDecisionSystems.2013.ANALYTICARelease4.4.LosGatos,CA.
Mahul,O.2003.Hedgingpriceriskinthepresenceofcropyieldandrevenueinsurance.EuropeanReviewofAgriculturalEconomics30(2):217239.
Mari,D.andD.,KotzS.2001.CorrelationandDependence.ImperialCollegePress.
McKinnon,R.I.1967.Futuresmarkets,bufferstocks,andincomestabilityforprimaryproducers.TheJournalofPoliticalEconomy,75(6),844861.
Miller,S.E.,andK.H.Kahl.1987.ForwardPricingWhenYieldsareUncertain.ReviewofFuturesMarkets,6,2139.
Nelson,R.,B.AnIntroductiontoCopulas(2nded.).SpringerInc.,2006.
Sherrick,B.J.,Zanini,F.C.,Schnitkey,G.D.,&Irwin,S.H.2004.Cropinsurancevaluationunderalternativeyielddistributions.AmericanJournalofAgriculturalEconomics,86(2),406419.
Sklar,A.1973.Randomvariables,jointdistributions,andcopulasKybernetica9,449460.
Tejeda,H.A.,&Goodwin,B.K.2008.ModelingcroppricesthroughaBurrdistributionandanalysisofcorrelationbetweencroppricesandyieldsusingacopulamethod.InannualmeetingoftheAgriculturalandAppliedEconomicsAssociation,Orlando,FL.
TrivediP.K.andZimmer,D.M.2005.CopulaModeling:AnIntroductionforPractitionersFoundationsandTrendsinEconometrics.1(1),1111.
USDARMANationalSummarybyInsurancePlan.2012.RetrievedJuly9,2012fromhttp://www.rma.usda.gov/data/sob.html
Vose,D.2008.RiskAnalysisAQuantitativeGuide.JohnWiley&SonsCo.
Wang,H.H.,Makus,L.D.,&Chen,X.2004.TheimpactofUScommodityprogrammesonhedginginthepresenceofcropinsurance.EuropeanReviewofAgriculturalEconomics,31(3),331352.
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Figure1Farm,County(HardinCounty),State(Kentucky),andNationalyielddistributions
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Figure2.DecemberFuturesPriceCumulativeDistributionFunction
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Figure3.FarmYieldCumulativeDistributionFunction
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Figure4.FarmRevenueRiskCDFwithandwithoutInsurance.
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Figure5.FarmRevenueRiskCDFHedgingwithandwithoutCropInsurance.
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Figure6.RevenueRiskCDF,Hedging(50%)andInsuranceacrossDifferentCoverageLevels
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Figure7.IncomeandTailRiskEfficientFrontierunderDifferentPortfolios.
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Figure8.AverageIncomewithandwithoutInsurance.
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