- MCMAHON SCAFFOLDING LTD- 07079677 - Incorporated on 18 November 2009 
- MCMAHON HOLDINGS LIMITED- 01896417 - Incorporated on 18 March 1985 
- MCMAHON ENGINEERING LIMITEDActive - Proposal to Strike off- SC431623 - Incorporated on 31 August 2012 
- MCMAHON MCLEAN LIMITEDActive - Proposal to Strike off- 06455692 - Incorporated on 18 December 2007 
- MCMAHON CONSULTING LTDActive - Proposal to Strike off- 07312453 - Incorporated on 13 July 2010 
- MCMAHON THOROUGHBREDS LTDDissolved- 07899570 - Dissolved on 31 March 2015 
- MCMAHON TRANSPORT LIMITEDDissolved- 01058962 - Dissolved on 6 July 2010 
- JAMES MCMAHON LIMITEDDisolved- 09032872 - Dissolved on 22 July 2021 
- LUDVIGSEN MCMAHON LIMITED- 09414108 - Incorporated on 30 January 2015 
- MCMAHON CATERING LIMITEDDissolved- 08818016 - Dissolved on 6 November 2018 
- MCMAHON CARPENTRY LTD- NI655913 - Incorporated on 25 September 2018 
- MCMAHON INDUSTRIAL LIMITEDActive - Proposal to Strike off- 10135462 - Incorporated on 20 April 2016 
- ADAM MCMAHON LIMITEDDisolved- 09902414 - Dissolved on 27 July 2021 
- MCMAHON ENGINEERING LTD- NI636907 - Incorporated on 7 March 2016 
- MCMAHON CONSULTING LTDDisolved- 10059274 - Dissolved on 5 April 2022 
- MCMAHON CONSTRUCTION LTD- 10453228 - Incorporated on 31 October 2016 
- MCMAHON MEDIA LIMITEDDisolved- 10606988 - Dissolved on 31 December 2024 
- CAMILLA MCMAHON LTDActive - Proposal to Strike off- 14813271 - Incorporated on 19 April 2023 
- MCMAHON CONSTRUCTION LTDDisolved- 15255310 - Dissolved on 22 April 2025 
- JACKSON MCMAHON LTDDisolved- SC824040 - Dissolved on 24 December 2024