曼昆《经济学原理》basic_tools--(汉魅HanMei—经济金融类汇总分享).ppt

27 TheBasicToolsofFinance Financeisthefieldthatstudieshowpeoplemakedecisionsregardingtheallocationofresourcesovertimeandthehandlingofrisk PRESENTVALUE MEASURINGTHETIMEVALUEOFMONEY Presentvaluereferstotheamountofmoneytodaythatwouldbeneededtoproduce usingprevailinginterestrates agivenfutureamountofmoney PRESENTVALUE MEASURINGTHETIMEVALUEOFMONEY Theconceptofpresentvaluedemonstratesthefollowing Receivingagivensumofmoneyinthepresentispreferredtoreceivingthesamesuninthefuture Inordertocomparevaluesatdifferentpointsintime comparetheirpresentvalues Firmsundertakeinvestmentprojectsifthepresentvalueoftheprojectexceedsthecost PRESENTVALUE MEASURINGTHETIMEVALUEOFMONEY Ifristheinterestrate thenanamountXtobereceivedinNyearshaspresentvalueof X 1 r N PRESENTVALUE MEASURINGTHETIMEVALUEOFMONEY FutureValueTheamountofmoneyinthefuturethatanamountofmoneytodaywillyield givenprevailinginterestrates iscalledthefuturevalue FYI Ruleof70 Accordingtotheruleof70 ifsomevariablegrowsatarateofxpercentperyear thenthatvariabledoublesinapproximately70 xyears MANAGINGRISK Apersonissaidtoberiskaverseifsheexhibitsadislikeofuncertainty MANAGINGRISK Individualscanreduceriskchoosinganyofthefollowing BuyinsuranceDiversifyAcceptalowerreturnontheirinvestments Figure1RiskAversion Wealth 0 Utility Current wealth Copyright 2004South Western TheMarketsforInsurance Onewaytodealwithriskistobuyinsurance Thegeneralfeatureofinsurancecontractsisthatapersonfacingariskpaysafeetoaninsurancecompany whichinreturnagreestoacceptallorpartoftherisk DiversificationofIdiosyncraticRisk Diversificationreferstothereductionofriskachievedbyreplacingasingleriskwithalargenumberofsmallerunrelatedrisks DiversificationofIdiosyncraticRisk Idiosyncraticriskistheriskthataffectsonlyasingleperson Theuncertaintyassociatedwithspecificcompanies DiversificationofIdiosyncraticRisk Aggregateriskistheriskthataffectsalleconomicactorsatonce theuncertaintyassociatedwiththeentireeconomy Diversificationcannotremoveaggregaterisk Figure2Diversification Numberof Stocksin Portfolio Morerisk Lessrisk 0 1 4 6 8 10 20 40 Risk standard deviationof portfolioreturn 30 Copyright 2004South Western DiversificationofIdiosyncraticRisk Peoplecanreduceriskbyacceptingalowerrateofreturn Figure3TheTradeoffbetweenRiskandReturn Risk standard deviation 0 5 10 15 20 8 3 3 1 Return percent peryear Copyright 2004South Western ASSETVALUATION Fundamentalanalysisisthestudyofacompany saccountingstatementsandfutureprospectstodetermineitsvalue ASSETVALUATION Peoplecanemployfundamentalanalysistotrytodetermineifastockisundervalued overvalued orfairlyvalued Thegoalistobuyundervaluedstock EfficientMarketsHypothesis Theefficientmarketshypothesisisthetheorythatassetpricesreflectallpubliclyavailableinformationaboutthevalueofanasset EfficientMarketsHypothesis Amarketisinformationallyefficientwhenitreflectsallavailableinformationinarationalway Ifmarketsareefficient theonlythinganinvestorcandoisbuyadiversifiedportfolio CASESTUDY RandomWalksandIndexFunds Randomwalkreferstothepathofavariablewhosechangesareimpossibletopredict Ifmarketsareefficient allstocksarefairlyvaluedandnostockismorelikelytoappreciatethananother Thusstockpricesfollowarandomwalk Summary Becausesavingscanearninterest asumofmoneytodayismorevaluablethanthesamesumofmoneyinthefuture Apersoncancomparesumsfromdifferenttimesusingtheconceptofpresentvalue Thepresentvalueofanyfuturesumistheamountthatwouldbeneededtoday givenprevailinginterestrates toproducethefuturesum Summary Becauseofdiminishingmarginalutility mostpeopleareriskaverse Risk aversepeoplecanreduceriskusinginsurance throughdiversification andbychoosingaportfoliowithlowerriskandlowerreturns Thevalueofanasset suchasashareofstock equalsthepresentvalueofthecashflowstheownerofthesharewillreceive includingthestreamofdividendsandthefinalsaleprice Summary Accordingtotheefficientmarketshypothesis financialmarketsprocessavailableinformationrational