| Little Earth Project Ltd | Manufacturing | 2021 |
| Little Green Court Management Company Limited | Households | 2026 |
| Little Oaks Wrap Around Care Ltd | Health & social care | 2019 |
| Little Properties Ltd | Construction | 2015 |
| Little Venice Boat Company Ltd | Arts & recreation | 2012 |
| Little White Box Interiors LLP | | 2019 |
| Loader Technology Limited | Manufacturing | 1999 |
| Lockeswood Management Company Limited | Households | 2016 |
| Lockett Flooring Limited | Financial services | 2023 |
| Lodestar Environments Ltd | Construction | 2021 |
| Logical Lawns Ltd | Administrative & support | 2024 |
| Long Melford Antiques & Interiors Warehouse Ltd | Wholesale & retail | 2020 |
| Long Melford Cricket Club Limited | Arts & recreation | 2018 |
| Long Melford Football Club 2002 Limited | Arts & recreation | 2002 |
| Long Melford Open Spaces C.I.C. | Real estate | 2012 |
| Loni Hand Car Wash Ltd | Administrative & support | 2026 |
| Loni Property Service Limited | Real estate | 2026 |
| Lookingood Hair and Beauty Ltd | Other services | 2023 |
| Lord MAY Holdings Limited | Real estate | 2020 |
| Lord MAY Partnership LLP | | 2020 |
| Louise Anthony Carpenters and Builders Limited | Administrative & support | 2016 |
| Louise Saunders Contractors Limited | Construction | 2023 |
| Love From Marnie Ltd | Wholesale & retail | 2022 |
| Love in the Hair Limited | Other services | 2019 |
| Love Lavenham CIC | Information & communication | 2022 |
| LPL UK Holdings Ltd | Wholesale & retail | 2022 |
| LPN Limited | Administrative & support | 2009 |
| LPS Ventures Ltd | Wholesale & retail | 2024 |
| LR Skipper Ltd | Hospitality | 2024 |
| LSJ Properties Ltd | Real estate | 2019 |
| Lucentra AI Ltd | Information & communication | 2026 |
| Luckhurst Consultants Limited | Real estate | 2026 |
| Lucward Co Limited | Financial services | 2007 |
| Lunar Thinking Limited | Professional & scientific | 2026 |
| Lungley Heat Co Limited | Wholesale & retail | 2026 |
| Luxsigns Limited | Other services | 2000 |
| M & F Pharma Quality Solutions Ltd | Professional & scientific | 2019 |
| M & M Drilling Services Ltd | Construction | 2026 |
| M a Design Interiors Ltd | Professional & scientific | 2020 |
| M J Border Holdings Limited | Financial services | 2024 |
| M J Bryant Electrical Limited | Manufacturing | 2004 |
| M J Chance Builders Limited | Construction | 2019 |
| M J Pearson Builders Limited | Construction | 2009 |
| M Stevenson Consulting Ltd | Professional & scientific | 2018 |
| M T Developments (East Anglia) Limited | Construction | 2016 |
| M&L Investment Properties Ltd | Real estate | 2020 |
| M.A.T. Ltd | Construction | 2007 |
| M.D. Mills (Building Contractors) Limited | Construction | 2003 |
| M.J.Body Repairs Ltd | Wholesale & retail | 2018 |
| M2 Storage Limited | Arts & recreation | 2024 |
| M3 Storage Limited | Arts & recreation | 2024 |
| Macawber UK Ltd | Manufacturing | 1994 |
| Mackman Ltd | Professional & scientific | 2003 |
| Made Electrical Ltd | Construction | 2023 |
| Madison & Lincoln Developments Ltd | Real estate | 2011 |
| Madorium Limited | Information & communication | 2022 |
| MAF Contracting Ltd | Wholesale & retail | 2019 |
| Magical Mail Limited | Manufacturing | 2019 |
| Magre Restaurants Limited | Hospitality | 2024 |
| Malam Concepts Limited | Professional & scientific | 2009 |
| Mamma’S Ministries CIC | Other services | 2025 |
| MAN of the World Pictures Limited | Information & communication | 2019 |
| Manbi Active Brands Ltd | Wholesale & retail | 2025 |
| Manbi Property Ltd | Real estate | 2025 |
| Mandana Developments Ltd | Construction | 2026 |
| Mandarin 166 Limited | Hospitality | 2023 |
| Mandarin Sudbury Limited | Hospitality | 2025 |
| Mander Auctioneers Ltd | Wholesale & retail | 2013 |
| Mander Property Holdings Limited | Real estate | 2024 |
| Mango Property Investments Limited | Real estate | 2018 |
| Manmoore Steel Construction Limited | Construction | 2024 |
| Mapby Limited | Energy | 2015 |
| Marbell Transport Solutions Ltd | Transport & logistics | 2020 |
| Margee Limited | Administrative & support | 1991 |
| Mario Drive Ltd | Transport & logistics | 2015 |
| Mark Loeffler Limited | Health & social care | 2010 |
| Markadept Ltd | Professional & scientific | 2021 |
| Market Hill Store Ltd | Wholesale & retail | 2026 |
| Market Regent Property Co Limited | Administrative & support | 2003 |
| Marshall Auto Locksmith Ltd | Wholesale & retail | 2025 |
| Marshfield MOT Ltd | Wholesale & retail | 2026 |
| Martin Group Limited | Financial services | 2015 |
| Master Home Care Ipswich Ltd | Administrative & support | 2025 |
| Matador HQ Ltd | Wholesale & retail | 2024 |
| Matthew Hynes Limited | Health & social care | 2013 |
| Mattock Motors Limited | Wholesale & retail | 2002 |
| Mawney Court Management Company Limited | Households | 2002 |
| Maysbrook Grove Number Two Residents Association Limited | Professional & scientific | 1999 |
| Mazan Limited | Hospitality | 2023 |
| Mazarine Ltd | Wholesale & retail | 2025 |
| MB Forklifts Ltd | Manufacturing | 2022 |
| MB LB Holdings Ltd | Real estate | 2025 |
| MBA Scaffolding Ltd | Construction | 2020 |
| Mbhb Limited | Financial services | 2020 |
| MC O’Neill Ltd | Professional & scientific | 2025 |
| MC Painting and Decorating Ltd | Construction | 2020 |
| Mccarter Construction Ltd | Construction | 2018 |
| MCJ Invest Limited | Real estate | 2016 |
| Mcknight Roofing Limited | Construction | 2021 |
| Mcmh Solutions Ltd | Wholesale & retail | 2023 |