| Memory Forest Ltd | Extraterritorial | 2023 |
| Merchant Taylors Residents Association (Ashwell) Limited | Professional & scientific | 2011 |
| Metal Transformation Ltd | Professional & scientific | 2025 |
| Methven Inns Ltd | Hospitality | 2017 |
| Metric Surveyors Limited | Real estate | 2015 |
| MGS Construction (UK) LLP | | 2009 |
| Michlex Limited | Construction | 2016 |
| Micropiling (Eastern) Limited | Construction | 1995 |
| Micropiling (London) Limited | Construction | 2015 |
| Middle Farm (Hinxworth) Ltd | Agriculture & fishing | 2007 |
| Minuendo UK Limited | Wholesale & retail | 2020 |
| Mitchell Countryside Services Ltd | Agriculture & fishing | 2026 |
| Mixa Production Limited | Financial services | 2020 |
| MJR Maritime Limited | Transport & logistics | 2017 |
| Mobius Artworks Limited | Arts & recreation | 2011 |
| Monty's Meadow LLP | | 2024 |
| Moonflower 42 Limited | Wholesale & retail | 2022 |
| MPH Engines Ltd | Manufacturing | 2023 |
| MR Duce Limited | Professional & scientific | 2015 |
| MSL Electrical Ltd | Administrative & support | 2005 |
| Mwclean Ltd | Administrative & support | 2021 |
| Mxtchday Ltd | Wholesale & retail | 2026 |
| N&D Tools Ltd | Wholesale & retail | 2018 |
| N5 Consultants Limited | Real estate | 2013 |
| Narrowa Ltd | Administrative & support | 2024 |
| Natural Corundum Limited | Wholesale & retail | 2022 |
| NE Quality Control Limited | Construction | 2024 |
| Negentropy Consulting Ltd | Information & communication | 2025 |
| Nemesis Commercial Limited | Real estate | 2013 |
| Newlook DRY Cleaners Baldock Limited | Other services | 2011 |
| Next Genz League Bedfordshire Ltd | Arts & recreation | 2026 |
| North Hertfordshire Construction Limited | Construction | 2016 |
| North Hertfordshire Developments Limited | Construction | 2022 |
| North Hertfordshire Group Limited | Financial services | 2022 |
| North Hertfordshire Plant Hire Limited | Administrative & support | 2022 |
| North Hertfordshire Properties Ltd | Real estate | 2018 |
| North Herts Angling Centre Limited | Wholesale & retail | 2003 |
| Nuwrld Limited | Wholesale & retail | 2021 |
| Nyrvana Ltd | Real estate | 2026 |
| Octree Limited | Information & communication | 2008 |
| OF Holdings Ltd | Hospitality | 2022 |
| Omega Luke Media Ltd | Other services | 2024 |
| One True Path Ltd | Professional & scientific | 2025 |
| Opalion Holdings Limited | Financial services | 2024 |
| Opalion Limited | Wholesale & retail | 1981 |
| Optim System Ltd | Financial services | 2016 |
| Orchestrator Ltd | Information & communication | 2026 |
| Oriental Trade Links Ltd | Wholesale & retail | 2024 |
| Orseno Limited | Information & communication | 2019 |
| Oscar Healy Ltd | Professional & scientific | 2017 |
| OSH Advisory Ltd | Professional & scientific | 2025 |
| Osstec Ltd | Professional & scientific | 2021 |
| Ours Collective Ltd | Wholesale & retail | 2025 |
| Owens Warehouse Limited | Wholesale & retail | 2022 |
| P & S Farms Limited | Agriculture & fishing | 1998 |
| Patina Art Collection Care Limited | Arts & recreation | 2008 |
| Paul Nicholas Limited | Construction | 2003 |
| Paul Watler Ltd. | Administrative & support | 2005 |
| PAW Print Dogalogue Co Limited(The) | Wholesale & retail | 1987 |
| PBS UK LLC | | 2011 |
| PDC Engineering Consulting Ltd | Professional & scientific | 2025 |
| Pemberton Technologies Limited | Manufacturing | 1996 |
| Pepper-Bowen Limited | Financial services | 2020 |
| Peter a Wright Electrical Limited | Construction | 2005 |
| Phoenix Property Rentals Ltd | Construction | 2020 |
| Physio Health Hub Ltd | Health & social care | 2026 |
| Platinum-Reg.Co.Uk Ltd | Wholesale & retail | 2024 |
| PMM Properties Limited | Real estate | 2026 |
| Polaris Evidence Ltd | Professional & scientific | 2021 |
| Positive Town Planning Limited | Professional & scientific | 2022 |
| Pragmateq Limited | Information & communication | 2017 |
| Premier Plant Services Ltd | Manufacturing | 2024 |
| Premier Power Services Ltd | Construction | 2023 |
| Prep Solutions Limited | Hospitality | 2023 |
| Print Badger Ltd | Manufacturing | 2021 |
| Product People Limited | Professional & scientific | 2012 |
| Property Together Ltd | Real estate | 2018 |
| PSB1970 Ltd | Construction | 2024 |
| Psplaserworld Limited | Information & communication | 2011 |
| Puddleducks Day Nursery (Baldock) Limited | Education | 2002 |
| Puffin Games Ltd | Information & communication | 2023 |
| Pugh Music Ltd | Information & communication | 2025 |
| Pulse Physio Ltd | Other services | 2006 |
| Pure Energy Wind Limited | Manufacturing | 2025 |
| Purple COW Developments Limited | Real estate | 2026 |
| Q.I.I. Limited | Administrative & support | 1998 |
| Qsheppard Ltd | Information & communication | 2015 |
| Quenby Bros. Limited | Wholesale & retail | 1938 |
| R & J B Limited | Professional & scientific | 2012 |
| R G Signs and Print Ltd | Manufacturing | 2022 |
| Radwell (Farms) Ltd | Construction | 2015 |
| Radwell Mill Ltd | Transport & logistics | 1985 |
| Rank and Role Ltd | Wholesale & retail | 2024 |
| Rapcatchup Limited | Information & communication | 2021 |
| RCW Logistics Ltd | Administrative & support | 2025 |
| RDO Architectural Design Ltd | Professional & scientific | 2025 |
| Re:New Coaching Ltd | Arts & recreation | 2023 |
| Rec-Onx Ltd | Information & communication | 2025 |
| Red Lift Hire Limited | Administrative & support | 2021 |
| Rehabilitation Innovations and Solutions Ltd | Professional & scientific | 2021 |