Does Going Public Affect Innovation(2)

Therestofthepaperproceedsasfollows.SectionIdescribesthedataandpresentssummarystatisticsandSectionIIpresentstheempiricalstrategy.SectionIIIprovidesthemainresultsandSectionIVdiscussespotentialchannels.SectionVconcludes.

Accepted ArticleI.Data

ThedatainthisanalysiscompriseinformationonIPO?lings,patents,hand-collected

?nancialinformation,andinformationonother?rmcharacteristics.

A.IPOFilings

ToapplyforanIPO,a?rmisrequiredtosubmitaninitialregistrationstatementtothe

SEC(usuallyFormS-1),whichcontainstheIPO?ler’sbusinessand?nancialinformation.FollowingthesubmissionoftheFormS-1,?lersmarkettheequityissuancetoinvestors(thebook-buildingphase)andhavetheoptiontowithdrawtheIPO?lingbysubmittingFormRW.WithdrawalsarecommoninIPOmarkets,withapproximately20%ofallIPO?lingsultimatelywithdrawn.

IcollectallIPO?lingsusingThomsonFinancial’sSDCNewIssuesdatabase.Thesample

startsin1985,whenSDCbegancoveringwithdrawnIPOssystematically,andendsin2003,astheanalysisexplorestheinnovationoutcomesof?rmsinthe?veyearsaftertheIPO?ling.FollowingtheIPOliterature,IexcludeIPO?lingsof?nancial?rms(SICbetween6000and6999),unito?ers,closed-endfunds(includingREITs),ADRs,limitedpartnerships,specialacquisitionvehicles,andspin-o?s.Iidentify5,583completeIPOsand1,599withdrawnIPO?lingsfrom1985to2003.

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B.PatentData

B.1.

MeasuringInnovativeActivity

Accepted ArticleAnextensiveliteratureontheeconomicsoftechnologicalchangedemonstratesthat

patentingactivityre?ectsthequalityandextentof?rminnovation,andtheuseofpatentingactivityasameasureofinnovationiswidelyaccepted(Hall,Ja?e,andTrajtenberg(2001),Lanjouw,Pakes,andPutnam(1998)).Importantlyforthisanalysis,patentinformationisavailableforbothpublicandprivate?rms,unlikeR&Dexpenditures,andallowstomeasure?rminnovationoutputalongseveraldimensions.

Themostbasicmeasureofinnovationoutputisasimplecountofthenumberofpatents

granted.However,patentcountscannotdistinguishbetweenbreakthroughinnovationandincrementaldiscoveries(e.g.,Griliches(1990)).Asecondmetricthereforere?ectsthenoveltyofapatentbycountingthenumberofcitationsapatentreceivesfollowingitsapproval.Thenumberofpatentcitationsalsocapturestheeconomicimportanceoftheinnovation,asitcorrelateswitha?rm’smarketvalue(Hall,Ja?e,andTrajtenberg(2005)).Indeed,Koganetal.(2012)showthatthestockmarketstrongly,andpositivelyreactstotheapprovalofpatentsthatareeventuallyhighlycited,andthatsuchpatentspredictboth?rmproductivityandcapitalandlabor?owsfromnon-innovativetoinnovative?rmswithintheindustry.Bothcitationratesandpatentcountsvaryovertimeandacrosstechnologies.Variation

maystemfromchangesintheimportanceoftechnologiesorfromchangesinthepatentsystem.Therefore,acomparisonofrawpatentsandcitationsisonlypartiallyinformative.Toadjustpatentcitations,IfollowHall,Ja?e,andTrajtenberg(2001)andconstructScaled

Citationsbyscalingeachpatentcitationcountbytheaveragenumberofcitationsofmatchedpatents,wherematchedpatentsarepatentsgrantedinthesameyearandinthesametechnologyclass.Similarly,toadjustpatentcounts,Iweighteachpatentbytheaveragenumberofpatentsgrantedby?rmsinthesameyearandtechnologyclass.Hence,patentsgrantedintechnologiesinwhich?rmsissuemorepatentsreceivelessweight.TheScaled

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NumberofPatentsisasimplesumofthescaledpatentsa?rmgeneratesinayear.AsadditionalmeasuresIemployOriginalityandGenerality,whichusethedistributionofcitationstocapturethefundamentalnatureofinnovation(Trajtenberg,Henderson,andJa?e(1997)).Apatentthatcitesabroaderarrayoftechnologyclassesisviewedashavinggreateroriginality,whileapatentthatiscitedbyamoretechnologicallyvariedarrayofpatentsisviewedashavinggreatergenerality.4Similarlytopatentcountsandcitations,ScaledOriginalityandScaledGeneralityarenormalizedbythecorrespondingaverageoriginalityorgeneralityofallpatentsgrantedinthesameyearandtechnologyclass.

B.2.PatentDataSources

ThepatentdatacomefromtheNationalBureauofEconomicResearch(NBER)patent

Accepted Articledatabase,whichincludesdetailedinformationonmorethanthreemillionpatentssubmittedtotheU.S.PatentandTrademarkO?ce(USPTO)from1976to2006(Hall,Ja?e,andTrajtenberg(2001)).

IusetheNBERbridge?letoCOMPUSTATtomatchpatentsto?rmsthatcompleted

theIPO?ling,andmanuallymatchpatentstowithdrawnIPO?lings.5Irestrictthesampleto?rmswithatleastonesuccessfulpatentapplicationovertheperiodfromthreeyearsbeforeto?veyearsaftertheIPO?ling.Thisyields1,488innovative?rmsthatwentpublicand323thatwithdrewtheIPOapplication.

Thegoalistocollectinformationon?rms’innovationactivityinthe?veyearsafterthe

IPO?lingregardlessofwhetherthe?rmsareacquiredorgopublicinasecondattempt,toavoidbiasesthatmayarisefromtruncating?rmactivity.Afterall,?rmexitsareyetanotherconsequenceoftheIPOe?ectthatin?uences?rms’innovationpaths.Collectingpatentinformationsubsequentto?rmexitsisfeasibleasinmostcases,evenifa?rmisacquired,itspatentsarestillassignedtotheacquiredratherthantheacquiringcompany.6

Icalculatethenumberofcitationsapatentreceivesinthecalendaryearofitsapprovalandinthesubsequentthreeyears.Thistimeframeisselectedto?tthenatureofthesample.

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SincemanyoftheIPO?lingsinthesampleoccurtowardtheendofthe1990s,increasingthetimehorizonofcitationcountswouldreducesamplesize.Furthermotivatingtheselectedcitationhorizonisthefactthatcitationsareconcentratedinthe?rstfewyearsfollowingapatent’sapproval,withaconsiderableserialcorrelationincitationrates(AkcigitandKerr(2013)).

SincetheNBERpatentdatabaseendsin2006,Isupplementitwithinformationfrom

Accepted ArticletheHarvardBusinessSchool(HBS)patentdatabase,whichcoverspatentsgrantedthroughDecember2009.Thisenablescalculationofcitationsforpatentsgrantedtowardtheendofthesample.Overall,thesampleconsistsof39,306granted …… 此处隐藏：651字，全部文档内容请下载后查看。喜欢就下载吧 ……