- MCWILLIAMS (DEVELOPMENTS) NI LTDDissolved- NI605112 - Dissolved on 12 December 2014 
- R.G. MCWILLIAMS (BUILDERS) LIMITED- NI007601 - Incorporated on 30 April 1969 
- MCWILLIAMS ENGINEERING SERVICES LTDActive - Proposal to Strike off- SC594532 - Incorporated on 17 April 2018 
- THE HARVEY MCWILLIAMS FOUNDATION- CE031824 
- MR & MRS O LTD.Active - Proposal to Strike off- SC217464 - Incorporated on 29 March 2001 
- MR & MRS W LTD- 08480767 - Incorporated on 9 April 2013 
- MR&MRS LTDActive - Proposal to Strike off- 10922002 - Incorporated on 18 August 2017 
- MR. & MRS. P LTD- 14381139 - Incorporated on 27 September 2022 
- MR&MRS LTDDisolved- 14548151 - Dissolved on 21 May 2024 
- MR MRG LTDDisolved- 14226733 - Dissolved on 19 December 2023 
- MR&MRS B.A.D LTDDisolved- 15544690 - Dissolved on 4 February 2025 
- TU FERGUSON LTDDisolved- 13636612 - Dissolved on 25 February 2025 
- MCWILLIAMS PSYCHOLOGICAL SERVICES LIMITED- 07139790 - Incorporated on 28 January 2010 
- MCWILLIAMS, DUDLEY & ASSOCIATES LIMITED- 03648396 - Incorporated on 12 October 1998 
- G MCWILLIAMS TRANSPORT LIMITEDActive - Proposal to Strike off- 08589359 - Incorporated on 28 June 2013 
- MR & MRS S LTDActive - Proposal to Strike off- 12290244 - Incorporated on 30 October 2019 
- C R & M M GRAHAM- SL004346 - Incorporated on 3 September 2001 
- FERGUSONS LTD- 05584455 - Incorporated on 6 October 2005 
- VP FERGUSON LTD- 11434125 - Incorporated on 26 June 2018 
- VG FERGUSON 8191 LTD- 10709927 - Incorporated on 5 April 2017