| Lucy's Fish Bar Ltd | Hospitality | 2017 |
| Ludo Khelo AUR Jeeto Limited | Information & communication | 2025 |
| Lugo Tech Limited | Information & communication | 2023 |
| Lugowski Ltd | Transport & logistics | 2014 |
| LUI Solutions Ltd | Water & waste | 2021 |
| Lukas 2 Lukas Limited | Construction | 2018 |
| Lukas Trans Haulage UK Ltd | Transport & logistics | 2016 |
| Lukas Trucker Ltd | Transport & logistics | 2021 |
| Luke & Dan's Garden Services Ltd | Administrative & support | 2022 |
| Luke Roberts Ltd | Extraterritorial | 2024 |
| Luke Scott and Sons Ltd | Construction | 2026 |
| Luke's - Spares Limited | Wholesale & retail | 2014 |
| Lukerouse Enterprise Ltd | Wholesale & retail | 2023 |
| Lumen IT Solutions Limited | Information & communication | 2023 |
| Lumin & Loom Ltd | Wholesale & retail | 2025 |
| Lumina Capital Ltd | Hospitality | 2026 |
| Luminexa Ltd | Real estate | 2017 |
| Lumley Close Freehold Company Limited | Households | 2018 |
| Lumos HC Ltd | Wholesale & retail | 2025 |
| Luna & Fennel Ltd | Manufacturing | 2019 |
| Luna Balloona Ltd | Arts & recreation | 2023 |
| Luna Comms Ltd | Information & communication | 2026 |
| Luno Residential Limited | Real estate | 2017 |
| Lush Cleans Ltd | Administrative & support | 2023 |
| Lush Luxury Homes Limited | Real estate | 2021 |
| Lushbelle Ltd | Manufacturing | 2014 |
| Lusi Connect Ltd | Transport & logistics | 2025 |
| LUX Design & Development Ltd | Construction | 2019 |
| LUX Swindon Ltd | Real estate | 2025 |
| Luxe Living Solutions (South West) Ltd | Manufacturing | 2026 |
| Luxframe Swindon Ltd | Construction | 2025 |
| Luxselect Ltd | Wholesale & retail | 2023 |
| Luxton Development Services Limited | Other services | 2021 |
| Luxtre Ltd | Wholesale & retail | 2025 |
| Luxury Events by SIA Ltd | Health & social care | 2019 |
| Luxury VIP Limos Ltd | Transport & logistics | 2021 |
| LV Express Services Ltd | Transport & logistics | 2024 |
| LW Electrical South West Ltd | Construction | 2025 |
| Lwandile Ltd | Public administration | 2019 |
| Lwks Software Ltd | Information & communication | 2020 |
| Lyal Contracts (Swindon) Ltd | Manufacturing | 2017 |
| Lyddons Engineering Limited | Information & communication | 2015 |
| Lydiard Car Care Ltd | Wholesale & retail | 2014 |
| Lydiard Fields Business Park Management Limited | Real estate | 2006 |
| Lynch Road Store PVT Ltd | Wholesale & retail | 2026 |
| Lynchford Road Lettings Limited | Real estate | 2023 |
| Lynmar Limited | Construction | 2025 |
| Lynt Byre Limited | Real estate | 2023 |
| Lynt Cottage Limited | Hospitality | 2019 |
| Lynx Communication Systems Limited | | 1981 |
| Lypiatt View Management Company Limited | Households | 2009 |
| Lyttle IT Limited | Information & communication | 2013 |
| M & a Bodywork Ltd | Wholesale & retail | 2025 |
| M & B Auto Centre Ltd | Wholesale & retail | 2019 |
| M & J Sealey Bricklaying Limited | Construction | 2003 |
| M & M Medical and Training Services Limited | Administrative & support | 2012 |
| M Adan & Umar Ltd | Wholesale & retail | 2026 |
| M and a Transport Service Limited | Transport & logistics | 2018 |
| M B Aviation Services Limited | Transport & logistics | 2020 |
| M B Decking Ltd | Manufacturing | 2022 |
| M Colombo Express Ltd | Wholesale & retail | 2025 |
| M Cripps Consultancy Limited | Information & communication | 2017 |
| M Evans Consulting Limited | Information & communication | 2007 |
| M Gough Plumbing & Heating Services Ltd | Construction | 2014 |
| M J B Developments (South West) Limited | Construction | 2008 |
| M J Freeth Services Limited | Manufacturing | 2018 |
| M J Gardner & Co. Ltd | Construction | 2005 |
| M J SLY Memorials Limited | Other services | 2013 |
| M JAY Property Group Limited | Real estate | 2026 |
| M L G a Ltd | Construction | 2010 |
| M Lanes Properties Ltd | Construction | 2020 |
| M Nicholls Physical Training Limited | Administrative & support | 2002 |
| M R H Builders Limited | Construction | 2003 |
| M R Pool Services Limited | Administrative & support | 2010 |
| M R V Swindon Ltd | Wholesale & retail | 2025 |
| M R Young & Sons (Rural) Limited | Agriculture & fishing | 2012 |
| M R Young & Sons LLP | | 2021 |
| M Richardson Carpentry Services Limited | Construction | 2008 |
| M T Supported Living Ltd | Health & social care | 2019 |
| M Tanning N Ltd | Other services | 2026 |
| M W Hair Services Ltd | Other services | 2018 |
| M W L Property Group Ltd | Real estate | 2026 |
| M&A Removals Limited | Transport & logistics | 2025 |
| M&A Tape and Jointing Limited | Construction | 2022 |
| M&C Holdings (Gloucester) Limited | Financial services | 2026 |
| M&F Consultanting Ltd | Professional & scientific | 2019 |
| M&K Property Rentals Ltd | Real estate | 2025 |
| M&M 4X Ltd | Financial services | 2025 |
| M&M Consultants Limited | Wholesale & retail | 2025 |
| M&M Euro Trans Ltd | Transport & logistics | 2021 |
| M&S Property Swindon Ltd | Real estate | 2025 |
| M&S Residential Ltd | Real estate | 2025 |
| M&S Van & Truck Rental Limited | Administrative & support | 2004 |
| M&V Chipaila Ltd | Health & social care | 2015 |
| M&W Kadosh Sushi Ltd | Hospitality | 2024 |
| M-Arc Heritage Limited | Professional & scientific | 2017 |
| M. Preymesser Logistics Limited | Transport & logistics | 2006 |
| M. Wheeler Contracting Ltd | Construction | 2017 |
| M. Wisniewska Limited | Other services | 2016 |
| M.A.D.E Art Ltd | Wholesale & retail | 2008 |