| Living Autism Limited | Health & social care | 2010 |
| Living Life With HS C.I.C. | Wholesale & retail | 2026 |
| LMA Joinery Limited | Construction | 2018 |
| LMB Property Developments Limited | Real estate | 2003 |
| Locom Engineering Limited | Manufacturing | 1996 |
| Lomas Contracts Ltd | Administrative & support | 2025 |
| Lomas Group Ltd | Financial services | 2023 |
| Long Folly Limited | Professional & scientific | 2016 |
| Longitude Plus Limited | Professional & scientific | 2019 |
| Lorne Limited | Extraterritorial | 2024 |
| Lotus Digital Ltd | Information & communication | 2017 |
| Lotus Marketing Ltd | Professional & scientific | 2024 |
| Lotus Pier Investments Limited | Construction | 2021 |
| Lou's Tyres Limited | Wholesale & retail | 1999 |
| Louise Robinson Limited | Health & social care | 2010 |
| Lowland Mechanical Services Limited | Professional & scientific | 2017 |
| LPL Limited | Information & communication | 1994 |
| Luca's Bistro at the Bosville Arms Ltd | Hospitality | 2025 |
| Lugano Metal Trading Limited | Manufacturing | 2019 |
| Lumenetic Ltd | Information & communication | 1978 |
| Luminosity Designs Ltd | Wholesale & retail | 2018 |
| Lund Automation Ltd | Information & communication | 2008 |
| Luvvey Limited | Wholesale & retail | 2013 |
| Luxurious Bathing Limited | Manufacturing | 2007 |
| Lycosa Web Services Ltd | Information & communication | 2002 |
| Lyon 2009 Limited | Professional & scientific | 2021 |
| M Field Limited | Agriculture & fishing | 2023 |
| M J Girking Limited | Agriculture & fishing | 1992 |
| M J Property (East Yorkshire) Ltd | Real estate | 2023 |
| M J Sharpless Limited | Manufacturing | 2015 |
| M J Thatcher Limited | Hospitality | 2020 |
| M K Multi Services Limited | Professional & scientific | 2025 |
| M P Joinery Ltd | Construction | 2021 |
| M W Syme Ltd | Construction | 2003 |
| M&L Home Studio Ltd | Arts & recreation | 2025 |
| Mackay Investments & Holdings Limited | Financial services | 2025 |
| Magic Action Promotions Limited | Arts & recreation | 1993 |
| Magic Shellfish Ltd | Agriculture & fishing | 2013 |
| Magna Inspections Limited | Construction | 2008 |
| Magna Welding Limited | Professional & scientific | 2012 |
| Magtion Ltd | Information & communication | 2025 |
| Main Line Optical Connections Limited | Professional & scientific | 2004 |
| Main Line Optical Limited | Professional & scientific | 2007 |
| Mainline Growers Limited | Agriculture & fishing | 2012 |
| Maja Associates Limited | Hospitality | 2012 |
| Majestyk Limited | Real estate | 2010 |
| Malton & Driffield Junction Railway Limited | Extraterritorial | 2014 |
| Malton Dodger Limited | Transport & logistics | 2010 |
| Mammoth Site Services Ltd | Professional & scientific | 2022 |
| Manor Inn (Fridaythorpe) Limited | Hospitality | 2023 |
| Manorfield Joinery and Properties Ltd | Construction | 2016 |
| Manorfield Medics Ltd | Health & social care | 2024 |
| Manu Forti Property Ltd | Real estate | 2025 |
| Mapa PR Ltd | Professional & scientific | 2014 |
| Mario's of Driffield Limited | Hospitality | 2025 |
| Mark Jibson Mechanical Engineering Limited | Professional & scientific | 2015 |
| Mark Warkup Limited | Agriculture & fishing | 2012 |
| Mason Farming | Agriculture & fishing | 2010 |
| Mason Food Safety Ltd | Professional & scientific | 2025 |
| Massey Farmers (Garton) Limited | Agriculture & fishing | 1975 |
| Master Pace Limited | Administrative & support | 2002 |
| Matt Johnson Joinery Services Limited | Construction | 2012 |
| Matt.Lorne Transport Ltd | Transport & logistics | 2000 |
| Matthew COX Plumbing Limited | Construction | 2013 |
| Maylec Ltd | Construction | 2020 |
| Maytree Education Consultancy Limited | Education | 2016 |
| MBP Civil Engineering Ltd | Construction | 2022 |
| Meadow & Mill Ltd | Manufacturing | 2025 |
| Medical Broking Company Limited | Financial services | 2016 |
| Megginson Livestock Partnership | | 1991 |
| Megginson Plant Hire Limited | Agriculture & fishing | 2018 |
| Mercantilism Limited | Professional & scientific | 2011 |
| Mercury Panel Products Limited | Manufacturing | 1969 |
| Mereside Developments (Yorkshire) Limited | Construction | 2013 |
| MG Aesthetics Limited | Other services | 2017 |
| MH3 Solutions Ltd | Administrative & support | 2023 |
| Mholdco Limited | Financial services | 2025 |
| Michelle Robinson Limited | Health & social care | 2024 |
| Mike Tuesday Management Limited | Administrative & support | 2015 |
| Milcot Engineering Services Limited | Professional & scientific | 1999 |
| Millington Limousins Limited | Agriculture & fishing | 2012 |
| Mini Piling Ltd | Construction | 2022 |
| MJM Farriers Ltd | Professional & scientific | 2020 |
| MLR Fabrications Ltd | Manufacturing | 2020 |
| MM Band Services Limited | Administrative & support | 2003 |
| MM Sellers Limited | Agriculture & fishing | 2004 |
| Mmbs Holdings Limited | Financial services | 2024 |
| Modest Lettings Limited | Real estate | 2024 |
| Monostore Limited | Construction | 2004 |
| Montgomery Marine Consultants Limited | Professional & scientific | 2011 |
| Montyredman Holdings Limited | Real estate | 2017 |
| Moowind 2 Limited | Energy | 2015 |
| Morris Maintenance Ltd | Professional & scientific | 2019 |
| Morrison Property Developments Ltd | Construction | 2020 |
| Motionx Socials Limited | Wholesale & retail | 2026 |
| MR Moo's CVP Limited | Energy | 2012 |
| MR Moo's Limited | Manufacturing | 2018 |
| MR Pickwick's Puzzle Palace Ltd | Wholesale & retail | 2014 |
| Mrcw Limited | Construction | 2012 |
| MRL Project Management Limited | Professional & scientific | 2014 |