| JRV Maintenance Solutions Ltd | Construction | 2026 |
| JS Services (Brighton) Ltd | Construction | 2012 |
| JS2 Investments Limited | Professional & scientific | 2011 |
| JSD Group Ltd | Hospitality | 2023 |
| Just Paws Ltd | Agriculture & fishing | 2017 |
| Just Praline Ltd | Financial services | 2023 |
| Justine Rattray Architecture Ltd | Professional & scientific | 2014 |
| JV Building Solutions Ltd | Construction | 2020 |
| JWS Europe Ltd | Manufacturing | 1994 |
| K & S Technology Limited | Wholesale & retail | 2005 |
| K and a Transportation Limited | Transport & logistics | 2023 |
| K G Taylor Limited | Construction | 2005 |
| Kaleido Studios Ltd | Professional & scientific | 2018 |
| Karis Homes Limited | Real estate | 2002 |
| Karl Scotland Ltd | Administrative & support | 2014 |
| Kate Hudson Limited | Administrative & support | 2009 |
| Kathleens Lodge Rest Home Ltd | Health & social care | 2012 |
| Keenground Properties Ltd | Real estate | 2020 |
| Keith John Rule Ltd | Extraterritorial | 2023 |
| Kemp Court Brighton Limited | Households | 2008 |
| Kendrick Property Services Limited | Real estate | 2012 |
| Kennedy Independent School Trust Limited | Education | 1966 |
| Kettle & Hobs Ltd | Wholesale & retail | 2025 |
| Key Frames Limited | Real estate | 1967 |
| Kick-Start Medical Ltd | Professional & scientific | 2025 |
| Kilim Furniture Ltd | Wholesale & retail | 2013 |
| Kingnel Management Company Limited | Households | 1984 |
| Kingsley Court Brighton Ltd | Households | 2018 |
| Kinsman Associates Limited | Arts & recreation | 1981 |
| Kirk Counselling Ltd | Education | 2019 |
| KIS Autocentres Technical Centre Ltd | Wholesale & retail | 2023 |
| KJR Enterprises Limited | Hospitality | 2019 |
| Klyra Management Consultancy Ltd. | Wholesale & retail | 2024 |
| Knight Construction Group Ltd | Construction | 2024 |
| Knight Electrical Solutions Ltd | Construction | 2022 |
| Kondition Limited | Arts & recreation | 2019 |
| Koning Electrical Ltd | Construction | 2023 |
| KS Audio Group Ltd | Professional & scientific | 2019 |
| KSD Hearing Ltd | Wholesale & retail | 2024 |
| Kspt Limited | Real estate | 2020 |
| Kurd's Plumbing & Heating Limited | Construction | 2018 |
| L&K Bitebox Ltd | Hospitality | 2025 |
| LA Cascada Magica Ltd | Information & communication | 2026 |
| LA Manga Limited | Real estate | 2025 |
| Laser and Skin Ltd | Extraterritorial | 2016 |
| Later Life Planning Ltd | Professional & scientific | 2013 |
| Lateral Channel Limited | Information & communication | 2012 |
| Lawdrum Properties Ltd | Real estate | 2025 |
| LED by Love Limited | Information & communication | 2023 |
| Ledicote Property Limited | Financial services | 2023 |
| Legentax Ltd | Professional & scientific | 2025 |
| Leopard Luxe Retail Ltd | Wholesale & retail | 2025 |
| LES Honess Sound Services Ltd | Manufacturing | 2003 |
| Lesser Foxholes Managementcompany Limited | Households | 1968 |
| Level UP Rentals and Developments Ltd | Real estate | 2025 |
| LFS Notary Services Limited | Professional & scientific | 2017 |
| Liberte UK Consultancy Ltd | Professional & scientific | 2022 |
| Library Bars Ltd | Hospitality | 2024 |
| Life and Soul Photography Ltd | Professional & scientific | 2026 |
| Lifesavers Together Ltd | Wholesale & retail | 2024 |
| Lift & Revive Ltd | Other services | 2023 |
| Lift and Shift Crane Hire Ltd | Construction | 2020 |
| Lift Seat Limited | Manufacturing | 2013 |
| Limehouse Brighton Ltd | Hospitality | 2012 |
| Lindi Technologies Limited | Information & communication | 2026 |
| Little Buckinghams Limited | Professional & scientific | 1997 |
| Little Scarfs Limited | Hospitality | 2025 |
| Livia Turco Limited | Arts & recreation | 2014 |
| LJT Property Consultants Ltd | Construction | 2025 |
| LMG Property Holdings Ltd | Real estate | 2024 |
| Load Relay Ltd | Information & communication | 2026 |
| Lombardi Bidco Limited | Financial services | 2024 |
| Long Reach Design Limited | Construction | 2022 |
| Longport Developments LLP | | 2007 |
| Lontano Records Limited | Information & communication | 1991 |
| Lontano Trust Limited | Arts & recreation | 1991 |
| Lorissa Page Consulting Ltd | Administrative & support | 2018 |
| Loughton Photographic Holdings Limited | Financial services | 2005 |
| Love IS a Red Dress Ltd | Arts & recreation | 2021 |
| Love Your Life Ltd | Health & social care | 2024 |
| Lovejoy Accounting Limited | Professional & scientific | 2022 |
| Lowmoor Road Limited | Professional & scientific | 2014 |
| LRS Service & Repair Ltd | Wholesale & retail | 2025 |
| LS Sports Coaching Ltd | Education | 2025 |
| Lucia Growth Ltd | Professional & scientific | 2025 |
| Lucinda Dore Solicitors Limited | Extraterritorial | 2014 |
| Lucy Davis Limited | Administrative & support | 2007 |
| Ludoforma Ltd | Professional & scientific | 2023 |
| Lumberjoe's Garden Services Limited | Administrative & support | 2022 |
| Luxe Landscaping Ltd | Professional & scientific | 2023 |
| LV Power Consulting Ltd | Professional & scientific | 2025 |
| LX Support Ltd | Arts & recreation | 2024 |
| Lynwood Properties Limited | Construction | 2012 |
| Lynwood Property Holdings Limited | Real estate | 2020 |
| Lyons & Sons (Garages) Ltd | Households | 2025 |
| M a O Mechanical Limited | Construction | 2019 |
| M&M Workforce Ltd | Administrative & support | 2024 |
| MA Mias Catering Ltd | Hospitality | 2025 |
| Mapleview Properties Limited | Real estate | 2002 |
| Marco Warren Fabrication Limited | Manufacturing | 2025 |