| Million Hairs (Elland) Limited | Other services | 2014 |
| Million Hairs (HX5) Ltd | Other services | 2025 |
| Milner Lodge Management Company Ltd | Households | 2013 |
| Ming Crystals Ltd | Wholesale & retail | 2021 |
| Mirfield Flat Management Company Limited | Households | 2005 |
| MJC Properties Limited | Real estate | 2018 |
| MJC Utilities Limited | Construction | 2016 |
| MJL Health Ltd | Arts & recreation | 2019 |
| Mknw Limited | Construction | 2013 |
| MMP Trans Ltd | Transport & logistics | 2020 |
| Modern Fire Extinguisher Services Limited | Other services | 1993 |
| Mollart Engineering Limited | Manufacturing | 1981 |
| Mollart Group Limited | Professional & scientific | 2016 |
| Mollart Holdings Limited | Professional & scientific | 1982 |
| Monarch Art Stone Holdings Limited | Financial services | 2026 |
| Moontex Bedding Company Limited | Wholesale & retail | 1988 |
| Moore Bakery Limited | Manufacturing | 2019 |
| Mortgage Inn Ltd | Professional & scientific | 2015 |
| Mortgage Innovations Ltd | Financial services | 2009 |
| Mount Charlotte Limited | Construction | 2008 |
| Mount Cook Limited | Real estate | 2008 |
| MPS Pension Trustees Limited | Extraterritorial | 2012 |
| MR Bradford Limited | Hospitality | 2019 |
| MSA Geotechnics Limited | Construction | 2026 |
| MW Construction Yorkshire Ltd | Construction | 2017 |
| Mwevci Ltd | Construction | 2024 |
| My Night Show Limited | Wholesale & retail | 2020 |
| Mybems Ltd | Administrative & support | 2021 |
| Mytholmroyd Electronics Company Limited | Professional & scientific | 1991 |
| N & a Percival (Ashtead) Ltd | Real estate | 2018 |
| N C Chicken & Sandwich Limited | Hospitality | 2019 |
| N D a Electrical Ltd | Manufacturing | 2011 |
| N.& A.Percival Limited | Administrative & support | 1971 |
| N02 ST Martins Management Company Limited | Households | 2012 |
| NA Cctv Ltd | Administrative & support | 2025 |
| Nationdrive Limited | Education | 2025 |
| Nearys Ltd | Construction | 2019 |
| Nevynweb Ltd | Information & communication | 2014 |
| New Durrani Jewellers Ltd | Wholesale & retail | 2017 |
| New Mill Management Company Limited | Real estate | 1996 |
| Newsome Holdings Limited | Real estate | 1974 |
| Nexaura Idea Ltd | Wholesale & retail | 2025 |
| Nexus Automation Ltd | Manufacturing | 2022 |
| Nigel Kyte Plumbing and Heating Engineer Limited | Construction | 2019 |
| NKG Haulage Solutions Ltd | Transport & logistics | 2018 |
| NLP Property (Halifax) Ltd | Real estate | 2024 |
| North Sports Group Limited | Wholesale & retail | 2023 |
| North Staffs Fire Limited | Public administration | 2010 |
| North West Breakdown Recovery Ltd | Transport & logistics | 2020 |
| Northern Construction Yorkshire Ltd | Construction | 2019 |
| Northern Estates and Properties Limited | Real estate | 1998 |
| Northerntrack Limited | Manufacturing | 1990 |
| Northgate Fabrications Ltd | Manufacturing | 2009 |
| Northlight Architecture Limited | Professional & scientific | 2005 |
| Northowram Paving and Driveways Ltd | Construction | 2017 |
| Northside 53 Management Company Limited | Real estate | 2022 |
| NU Construction Limited | Construction | 2003 |
| Nu-Fit Pvcu Windows & Doors Limited | Manufacturing | 2009 |
| Nu-Swift (Engineering) Limited | Manufacturing | 1994 |
| Nu-Swift International Limited | Manufacturing | 1933 |
| Nu-Swift Limited | Professional & scientific | 1995 |
| O.H. Steel Founders and Engineers Limited | Professional & scientific | 1967 |
| Oakview Fencing Supplies Ltd | Administrative & support | 2020 |
| Oates Developments Limited | Construction | 2022 |
| Occasions Cakes & Bakes Ltd | Hospitality | 2023 |
| Odin Lab's Ltd | Manufacturing | 2025 |
| Odinriskmanagement Limited | Financial services | 2022 |
| OFF Site App Ltd | Information & communication | 2026 |
| Old Coach Buildings Ltd | Real estate | 2013 |
| Old Earth School | Education | 2011 |
| Old Willow Developments Ltd | Construction | 2017 |
| Oldham Premier Plumbing Supplies Ltd | Wholesale & retail | 2012 |
| Ollerton Limited | Manufacturing | 2001 |
| Omega One Ltd | Administrative & support | 2025 |
| Omnicrete Limited | Extraterritorial | 2008 |
| OMR Developments Limited | Other services | 2015 |
| ON Trend Group Ltd | Manufacturing | 2019 |
| One Stop Automotive Ltd | Wholesale & retail | 2017 |
| One Stop Electrical Contractors Ltd | Construction | 2022 |
| Oneshot Estates Ltd | Real estate | 2025 |
| Oneshot Group Ltd | Construction | 2023 |
| Onewayfinance Ltd | Financial services | 2020 |
| Optimus International Ltd | Wholesale & retail | 2022 |
| Orchard First Fruits Limited | Real estate | 2016 |
| Oriental Direct Limited | Wholesale & retail | 2010 |
| Ossett 40 Limited | Construction | 2017 |
| Oulton 30 (Aberford RD) Ltd | Construction | 2020 |
| Oulton 30 Leeds Limited | Real estate | 2015 |
| Oulton 30 North West Ltd | Construction | 2025 |
| Oulton 30 Wakefield Ltd | Construction | 2016 |
| OUR Assets Ltd | Real estate | 2020 |
| Overgate Hospice Support Ltd | Administrative & support | 2009 |
| Oxford Lane Management Company Limited | Households | 2005 |
| Paddock Lodge Care Home Limited | Health & social care | 2017 |
| Panablok (UK) Ltd. | Professional & scientific | 1994 |
| Panel Processing Consultants Ltd | Financial services | 2014 |
| Paramount Auto Transport Ltd | Transport & logistics | 2020 |
| Park Lane Plaza (Liverpool) Management Company Limited | Extraterritorial | 2006 |
| Parkside Management (Plots 55 to 62) Limited | Households | 1994 |
| Parkview Court (Bradford) Management Company Limited | Households | 1996 |