- K.E. O'BRIEN LIMITED- 06941234 - Incorporated on 23 June 2009 
- D.M. O'BRIEN LIMITEDDissolved- 02504822 - Dissolved on 19 November 2013 
- STEVE O'BRIEN LTDDissolved- 07948806 - Dissolved on 1 October 2019 
- K & B O'BRIEN LIMITEDActive - Proposal to Strike off- 08285145 - Incorporated on 7 November 2012 
- B BRIEN LIMITEDActive - Proposal to Strike off- 08692670 - Incorporated on 16 September 2013 
- R T O'BRIEN LIMITEDActive - Proposal to Strike off- 04675493 - Incorporated on 24 February 2003 
- AIMEE O'BRIEN 6408 LTDActive - Proposal to Strike off- 10331783 - Incorporated on 16 August 2016 
- CARTY O'BRIEN LTD- NI633825 - Incorporated on 23 September 2015 
- O'BRIEN LEISURE LTDActive - Proposal to Strike off- 07512470 - Incorporated on 1 February 2011 
- K.G. O'BRIEN FLOORING LIMITEDDissolved- 04473055 - Dissolved on 7 March 2012 
- MR MRG LTDDisolved- 14226733 - Dissolved on 19 December 2023 
- MR&MRS B.A.D LTDDisolved- 15544690 - Dissolved on 4 February 2025 
- H W O'BRIEN LIMITEDDissolved- 04866854 - Dissolved on 12 February 2019 
- R.J. O'BRIEN LIMITED- 01810354 - Incorporated on 19 April 1984 
- DR. SINEAD O'BRIENActive - Proposal to Strike off- NI605325 - Incorporated on 30 November 2010 
- DR. CELINE O'BRIENActive - Proposal to Strike off- NI606251 - Incorporated on 21 February 2011 
- DR LAOISE O'BRIEN- NI625708 - Incorporated on 16 July 2014 
- M L O'BRIEN LIMITED- 09023869 - Incorporated on 6 May 2014 
- E A O'BRIEN LIMITEDDisolved- 11911895 - Dissolved on 22 August 2023 
- SHAUN O'BRIEN LTDDisolved- 14470733 - Dissolved on 16 April 2024