QuickLinks -- Click here to rapidly navigate through this document

EXHIBIT 21

INTERNATIONAL BUSINESS MACHINES CORPORATION SUBSIDIARIES

Subsidiaries—as of December 31, 2013

Company Name	State or country of incorporation or organization	Voting percent owned directly or indirectly by registrant
IBM Argentina Sociedad de Responsabilidad Limitada	Argentina		100
IBM Australia Limited	Australia		100
IBM Oesterreich Internationale Bueromaschinen Gesellschaft m.b.H.	Austria		100
IBM Bahamas Limited	Bahamas		100
IBM Bangladesh Private Limited	Bangladesh		100
IBM Foreign Sales Corporation	Barbados		100
International Business Machines of Belgium sprl/buba	Belgium		100
WTC Insurance Corporation, Ltd.	Bermuda		100
IBM Brasil—Industria, Maquinas e Servicos Limitada	Brazil		100
IBM Bulgaria Ltd.	Bulgaria		100
IBM Burkina Faso SARL	Burkina Faso		100
IBM Canada Limited—IBM Canada Limitee	Canada		100
IBM Tchad SARLU	Chad		100
IBM de Chile S.A.C.	Chile		100
IBM (China) Investment Company Limited	China (P.R.C.)		100
IBM de Colombia & C.I.A. S.C.A.	Colombia		100
IBM Congo SARL	Congo		100
IBM RDC	Congo Republic		100
IBM Business Transformation Center, S.r.l.	Costa Rica		100
IBM Croatia Ltd./IBM Hrvatska d.o.o.	Croatia		100
IBM Ceska Republika spol. s.r.o.	Czech Republic		100
IBM Danmark ApS	Denmark		100
IBM del Ecuador, C.A.	Ecuador		100
IBM Egypt Business Support Services	Egypt		100
IBM Eesti Osauhing (IBM Estonia Ou)	Estonia		100
Oy IBM Finland AB	Finland		100
Compagnie IBM France, S.A.S.	France		100
International Business Machines Gabon SARL	Gabon		100
IBM Deutschland GmbH	Germany		100
International Business Machines Ghana Limited	Ghana		100
IBM Hellas Information Handling Systems S.A.	Greece		100
IBM China/Hong Kong Limited	Hong Kong		100
IBM Magyarorszagi Kft.	Hungary		100
IBM India Private Limited	India		100
PT IBM Indonesia	Indonesia		100
IBM Ireland Limited	Ireland		100
IBM Ireland Product Distribution Limited	Ireland		100
IBM Israel Limited	Israel		100
IBM Italia S.p.A.	Italy		100
IBM Japan, Ltd.	Japan		100
IBM East Africa Limited	Kenya		100
IBM Korea, Inc.	Korea (South)		100
Sabiedriba ar irobezotu atbildibu IBM Latvija	Latvia		100
IBM Lietuva	Lithuania		100
IBM Services Financial Sector Luxembourg Sarl	Luxembourg		100
International Business Machines Madagascar SARLU	Madagascar		100

Company Name	State or country of incorporation or organization	Voting percent owned directly or indirectly by registrant
International Information Services Management Limited	Malawi		100
IBM Malaysia Sdn. Bhd.	Malaysia		100
IBM Malta Limited	Malta		100
IBM Mauritius	Mauritius		100
IBM de Mexico, S. de R.L.	Mexico		100
IBM Maroc	Morocco		100
IBM International Group B.V.	Netherlands		100
IBM Nederland B.V.	Netherlands		100
IBM New Zealand Limited	New Zealand		100
IBM Niger SARLU	Niger		100
International Business Machines West Africa Limited	Nigeria		100
International Business Machines AS	Norway		100
IBM del Peru, S.A.	Peru		100
IBM Philippines, Incorporated	Philippines		100
IBM Polska Sp.z.o.o.	Poland		100
Companhia IBM Portuguesa, S.A.	Portugal		100
IBM Qatar SSC	Qatar		100
IBM Romania Srl	Romania		100
IBM East Europe/Asia Ltd.	Russia		100
International Business Machines Senegal	Senegal		100
IBM—International Business Machines d.o.o., Belgrade	Serbia		100
International Information Services Management Limited	Seychelles		100
IBM Limited	Sierra Leone		100
IBM Singapore Pte. Ltd.	Singapore		100
IBM Slovensko spol s.r.o.	Slovak Republic		100
IBM Slovenija d.o.o.	Slovenia		100
IBM South Africa (Pty) Ltd.	South Africa		100
International Business Machines, S.A.	Spain		100
IBM Svenska Aktiebolag	Sweden		100
IBM Schweiz AG—IBM Suisse SA—IBM Suizzera SA—IBM Switzerland Ltd.	Switzerland		100
IBM Taiwan Corporation	Taiwan		100
IBM Tanzania Limited	Tanzania		100
IBM Thailand Company Limited	Thailand		100
IBM Tunisie	Tunisia		100
IBM (International Business Machines) Turk Limited Sirketi	Turkey		100
Technology Products and Services Limited	Uganda		100
IBM Ukraine	Ukraine		100
IBM Middle East FZ—LLC	United Arab Emirates		100
IBM United Kingdom Limited	United Kingdom		100
IBM del Uruguay, S.A.	Uruguay		100
IBM Capital Inc.	USA (Delaware)		100
IBM Credit LLC	USA (Delaware)		100
IBM International Group Capital LLC	USA (Delaware)		100
IBM International Foundation	USA (Delaware)		100
IBM World Trade Corporation	USA (Delaware)		100
IBM de Venezuela, S.A.	Venezuela		100
IBM Vietnam Company	Vietnam		100
International Business Machines Zambia Limited	Zambia		100

QuickLinks

EXHIBIT 21

INTERNATIONAL BUSINESS MACHINES CORPORATION SUBSIDIARIES