Sign in

Private company

Rational Software

Logo: Unknown author Unknown author, Public domain, via Wikimedia Commons3

Defunct software company

Rational Machines was an enterprise founded by Paul Levy and Mike Devlin in 1981 to provide tools to expand the use of modern software engineering practices, particularly explicit modular architecture and iterative development. It changed its name in 1994 to Rational Software, and was sold for US$2.1 billion (equivalent to current US$3.68 billion) to IBM on February 21, 2003.2 Wikipedia text CC BY-SA 4.0

Last updated Oct 21, 2026.

Overview

1991Founded1

See how the biggest companies compare on our leaderboards

Rational Machines was an enterprise founded by Paul Levy and Mike Devlin in 1981 to provide tools to expand the use of modern software engineering practices, particularly explicit modular architecture and iterative development. It changed its name in 1994 to Rational Software, and was sold for US$2.1 billion (equivalent to current US$3.68 billion) to IBM on February 21, 2003.2

Corporate structure

Rational Software is part of a group headed by IBM. 224 entities, 71 countries on record. Switch between the flow chart and the network, and select any entity to see its details.

  • IBM North Castle, New York, United States
    • IBM India Private Limited 100% · Bangalore, India
    • Confluent Inc. Mountain View, California, United States
      • Confluent Australia Pty Limited Subsidiary · Australia
      • Confluent Brazil Ltda. Subsidiary · Brazil
      • Confluent Czech Republic S.R.O. Subsidiary · Czechia
      • Confluent Europe Ltd. Subsidiary · United Kingdom
      • Confluent France SAS Subsidiary · France
      • Confluent Germany GmbH Subsidiary · Germany
      • Confluent Hong Kong Ltd Subsidiary · Hong Kong
      • CONFLUENT INDIA PRIVATE LIMITED Subsidiary · Mumbai, India
      • Confluent Ireland Software Limited Subsidiary · Ireland
      • Confluent Israel Ltd. Subsidiary · Israel
      • Confluent Italy S.R.L. Subsidiary · Italy
      • Confluent Japan Godo Kaisha Subsidiary · Japan
      • Confluent Korea Limited Subsidiary · South Korea
      • Confluent Malaysia Sdn. Bhd. Subsidiary · Malaysia
      • Confluent ME FZ-LLC Subsidiary · United Arab Emirates
      • Confluent Netherlands B.V. Subsidiary · Netherlands
      • Confluent Poland sp. z o.o. Subsidiary · Poland
      • Confluent Singapore Pte. Ltd. Subsidiary · Singapore
      • Confluent Spain, Sociedad Limitada Subsidiary · Spain
      • Confluent Sweden AB Subsidiary · Sweden
      • Confluent Switzerland GmbH Subsidiary · Switzerland
      • Infinitem Canada Ltd. Subsidiary · Canada
    • IBM GLOBAL FINANCING INVESTMENTS I B.V. Amsterdam, Netherlands
    • IBM INTERNATIONAL GROUP B.V. Amsterdam, Netherlands
      • IBM Norge Oslo, Norway
      • IBM DANMARK ApS Subsidiary · Brondby, Denmark
      • IBM LUXEMBOURG S.a r.l. (IBM LUXEMBOURG S.à r.l.) Subsidiary · Belvaux, Luxembourg
      • International Business Machines of Belgium Subsidiary · Brussel, Belgium
    • IBM ITALIA S.P.A. Segrate, Italy
      • Dock Joined In Tech S.R.L. Subsidiary · Segrate, Italy
      • IBM SOUTH AFRICA Subsidiary · Johannesburg, South Africa
      • SISTEMI INFORMATIVI S.R.L. Subsidiary · Roma, Italy
    • IBM Japan 港区, Japan
      • IT Frontier Subsidiary
    • IBM Korea 서울, South Korea
    • IBM SCHWEIZ AG Zurich, Switzerland
      • IBM Bulgaria 100% · Sofia, Bulgaria
      • IBM SLOVENIJA Podjetje za proizvodnjo, marketing in storitve d.o.o. Ljubljana Subsidiary · 100% · Ljubljana, Slovenia
    • IBM Svenska AB Stockholm, Sweden
    • Rational Software
    • Red Hat Wilmington, Delaware, United States
      • Red Hat Czech Brno, Czechia
      • Inktank Storage Subsidiary · Los Angeles
      • Red Hat (Israel) Subsidiary · Ra'Anana, Israel
      • Red Hat (United Kingdom) Subsidiary · Farnborough, United Kingdom
      • Red Hat Germany Subsidiary · Grasbrunn, Germany
      • StackRox Subsidiary · Mountain View
      • RED HAT ASIA PACIFIC PTE LTD Subsidiary · Raleigh, North Carolina, United States
      • RED HAT LIMITED Subsidiary · Cork, Ireland
        • RED HAT INDIA PRIVATE LIMITED Subsidiary · Raleigh, North Carolina, United States
      • ROUND POND UNLIMITED COMPANY Subsidiary · Dublin, Ireland
    • IBM Denmark Subsidiary · 100%
    • IBM France Subsidiary · 100% · Paris, France
    • IBM Germany Subsidiary · 100% · Ehningen, Germany
    • SoftLayer Subsidiary · 100% · Dallas
    • AlchemyAPI Subsidiary · Denver
    • Algorithmics Inc. Subsidiary · Toronto
    • Cloudant Subsidiary · Boston
    • Cognos Subsidiary · Ottawa
    • Dehomag Subsidiary · Berlin
    • IBM (Spain) Subsidiary · Madrid, Spain
    • IBM Canada Subsidiary · Markham, Ontario, Canada
    • IBM Cloud Video Subsidiary · San Francisco
    • IBM Global Financing Subsidiary · North Castle, New York, United States
    • IBM Global Services Subsidiary · Armonk
    • and 145 more

Built from parent and subsidiary links from GLEIF, the Global Legal Entity Identifier Foundation (CC0); subsidiaries listed in Exhibit 21 of annual reports filed with the SEC; subsidiaries, stakes and holdings from Wikidata (CC0). Each entity in the chart links to its source.

The story

Founded by Mike Devlin in 1991.1

Leadership

Who has led Rational Software, and when. Pick a name to see everywhere that person has worked.

Products and brands

  • software

Listed on Wikidata.1

Subsidiaries and ownership

Parent company

From Wikidata.1

Timeline

  1. 2003Dissolved Dissolved1
  2. 1991Founded Founded1

Sources

The numbers on this page point here. Each one links to the record it came from.

  1. 1
  2. 2
  3. 3