From what I gather [2], WHOIS often matches sub-domains before top-level-domains, making it easy for someone to create a sub-domain such as 'microsoft.foobar.com' with false records that will populate before the actual domain.
It seems that using the following WHOIS query returns registrar information for Microsoft.com, though it requires sifting through the 'spoofed' results: 'WHOIS =Microsoft.com' [3]. You'll have to wade to the bottom of the results.
[1] MICROSOFT.COM.ARE.GODDAMN.PIGFUCKERS.NET.NS-NOT-IN-SERVICE.COM MICROSOFT.COM.CAN.GO.FUCK.ITSELF.AT.SECZY.COM MICROSOFT.COM.EENGURRA.COM MICROSOFT.COM.FILLS.ME.WITH.BELLIGERENCE.NET MICROSOFT.COM.HAS.A.PRESENT.COMING.FROM.HUGHESMISSILES.COM MICROSOFT.COM.IS.A.MESS.TIMPORTER.CO.UK MICROSOFT.COM.IS.A.STEAMING.HEAP.OF.FUCKING-BULLSHIT.NET MICROSOFT.COM.IS.IN.BED.WITH.CURTYV.COM MICROSOFT.COM.IS.NICE.WHEN.TOASTED.COMKAL.NET MICROSOFT.COM.IS.NOT.HOSTED.BY.ACTIVEDOMAINDNS.NET MICROSOFT.COM.IS.NOT.YEPPA.ORG MICROSOFT.COM.LIVES.AT.SHAUNEWING.COM MICROSOFT.COM.LOVES.ME.KOSMAL.NET MICROSOFT.COM.MAKES.RICKARD.DRINK.SAMBUCA.0800CARRENTAL.COM MICROSOFT.COM.MATCHES.THIS.STRING.AT.KEYSIGNERS.COM MICROSOFT.COM.MORE.INFO.AT.WWW.BEYONDWHOIS.COM MICROSOFT.COM.RAWKZ.MUH.WERLD.MENTALFLOSS.CA MICROSOFT.COM.SHOULD.GIVE.UP.BECAUSE.LINUXISGOD.COM MICROSOFT.COM.SHOULD.INSTALL-GENTOO.NET MICROSOFT.COM.SOFTWARE.IS.NOT.USED.AT.REG.RU MICROSOFT.COM.WAREZ.AT.TOPLIST.GULLI.COM MICROSOFT.COM.WILL.BE.BEATEN.WITH.MY.SPANNER.NET MICROSOFT.COM.WILL.BE.SLAPPED.IN.THE.FACE.BY.MY.BLUE.VEINED.SPANNER.NET MICROSOFT.COM.ZZZ.IS.0WNED.AND.HAX0RED.BY.SUB7.NET MICROSOFT.COM.ZZZZZ.GET.LAID.AT.WWW.SWINGINGCOMMUNITY.COM MICROSOFT.COM.ZZZZZZ.MORE.DETAILS.AT.WWW.BEYONDWHOIS.COM MICROSOFT.COM.ZZZZZZZ.LOLLERSKATES.RENDRAG.NET MICROSOFT.COM.ZZZZZZZZZZZZZZZZZZ.IM.ELITE.WANNABE.TOO.WWW.PLUS613.NET MICROSOFT.COM.ZZZZZZZZZZZZZZZZZZZ.GET.ONE.MILLION.DOLLARS.AT.WWW.UNIMUNDI.COM MICROSOFT.COM.ZZZZZZZZZZZZZZZZZZZZ.LOLLERSKATES.RENDRAG.NET MICROSOFT.COM.ZZZZZZZZZZZZZZZZZZZZZZ.IS.A.GREAT.COMPANY.ITREBAL.COM MICROSOFT.COM
[2] http://www.securiteam.com/securitynews/6D00L0K00G.html
[3] Domain Name: MICROSOFT.COM Registrar: MARKMONITOR INC. Sponsoring Registrar IANA ID: 292 Whois Server: whois.markmonitor.com Referral URL: http://www.markmonitor.com Name Server: NS1.MSFT.NET Name Server: NS2.MSFT.NET Name Server: NS3.MSFT.NET Name Server: NS4.MSFT.NET