- O'SULLIVAN & EDMONDS LIMITED- 08400333 - Incorporated on 13 February 2013 
- SINEAD O'SULLIVAN LIMITED- 08414678 - Incorporated on 21 February 2013 
- O'SULLIVAN SWANSEA LIMITED- 08983872 - Incorporated on 8 April 2014 
- O'SULLIVAN-SMITH LTD- 09051531 - Incorporated on 22 May 2014 
- MICHAEL O'SULLIVAN LIMITEDActive - Proposal to Strike off- 09090922 - Incorporated on 18 June 2014 
- CHRIS O'SULLIVAN LIMITED- 09104029 - Incorporated on 26 June 2014 
- O'REILLY & O'SULLIVAN LLP- OC397438 - Incorporated on 12 January 2015 
- MOLLY O'SULLIVAN LIMITEDActive - Proposal to Strike off- 10337878 - Incorporated on 19 August 2016 
- BRENDAN O'SULLIVAN LIMITEDActive - Proposal to Strike off- 10413573 - Incorporated on 6 October 2016 
- PAUL O'SULLIVAN LIMITED- 10872850 - Incorporated on 19 July 2017 
- O'SULLIVAN CONSULTANCY LIMITEDActive - Proposal to Strike off- 10973978 - Incorporated on 21 September 2017 
- SAM O'SULLIVAN LTD.- 11124878 - Incorporated on 27 December 2017 
- DON O'SULLIVAN LTD- 11148463 - Incorporated on 15 January 2018 
- O'SULLIVAN VENTURES LTD- 15909594 - Incorporated on 21 August 2024 
- O'SULLIVAN HUGHES LIMITED- 16532392 - Incorporated on 20 June 2025 
- 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