| Summerlea Gardens Management Company (Littlehampton) Limited | Households | 1971 |
| Summerley Point Properties Co Ltd | Households | 2020 |
| Summerley Point Residents Management Company Limited | Households | 2015 |
| Summers Close Residents Limited | Households | 2005 |
| Summit Point Digital Ltd | Professional & scientific | 2025 |
| Summit Tasty Ltd | Hospitality | 2022 |
| Sun Court (Worthing) Management Company Limited | Households | 1978 |
| Sun Earth Energy Ltd | Construction | 2012 |
| Sun WAH 134 Limited | Hospitality | 2022 |
| Sunflower Child Day Care Ltd | Health & social care | 2025 |
| Sunflower Social Limited | Hospitality | 2026 |
| Sunnydown Court Residents' Association Limited | Professional & scientific | 1999 |
| Sunshine & Bear Limited | Professional & scientific | 2018 |
| Sunshine Studio East Preston Ltd | Other services | 2025 |
| Superior Exterior Cleaning & Maintenance Ltd | Administrative & support | 2026 |
| Supernatural Distribution Ltd | Transport & logistics | 2020 |
| Surf 50 Limited | Other services | 2009 |
| Surfing Camel Ltd | Wholesale & retail | 2016 |
| Surge Electrical Contractors UK Limited | Construction | 2021 |
| Surkle Limited | Information & communication | 2021 |
| Surrey Cottage Limited | Households | 2000 |
| Surrey Hills Plastering Limited | Construction | 2014 |
| Susi Ltd | Construction | 2026 |
| Sussex and Surrey Garden Rooms Ltd | Construction | 2026 |
| Sussex Appliance Ltd | Wholesale & retail | 2024 |
| Sussex Auto Centre Limited | Wholesale & retail | 2009 |
| Sussex Business Solutions Ltd | Information & communication | 2016 |
| Sussex Carpentry & Joinery Limited | Construction | 2018 |
| Sussex Court (Barnham) Management Company Limited | Households | 2001 |
| Sussex Design Interiors Limited | Manufacturing | 2006 |
| Sussex Eco Solutions Limited | Construction | 2009 |
| Sussex Mobiles Limited | Wholesale & retail | 2013 |
| Sussex Orthopaedic Clinic Limited | Health & social care | 2005 |
| Sussex Orthopaedic Solutions Limited | Health & social care | 2007 |
| Sussex Parts Hub Ltd | Wholesale & retail | 2023 |
| Sussex Road and Race Limited | Wholesale & retail | 2015 |
| Sussex Stays LLP | | 2023 |
| Sussex Velo Ltd | Wholesale & retail | 2014 |
| Sutton Plumbing Ltd | Construction | 2015 |
| SW Power Services Ltd | Construction | 2011 |
| Swanbourne Park Management Company Limited | Households | 2015 |
| Sweet Coast Limited | Wholesale & retail | 2017 |
| Sweetpeas and Honeybees Boutique Florists Ltd. | Wholesale & retail | 2014 |
| Swift Half Enterprises Ltd | Arts & recreation | 2021 |
| Swindens Vices Ltd | Manufacturing | 2026 |
| Swyce Interiors Ltd | Construction | 2016 |
| Sylvatica Homes Limited | Real estate | 2015 |
| Szalka Homes Developments Ltd | Construction | 2025 |
| T & DG Property Ltd | Real estate | 2018 |
| T and T Cleaning UK Ltd | Administrative & support | 2019 |
| T M Appliance Services Ltd | Other services | 2012 |
| T M GAS Services Ltd | Construction | 2018 |
| T Tudor Ltd | Hospitality | 2019 |
| T&C Travel Limited | Transport & logistics | 2019 |
| T. Lewis Design Ltd | Professional & scientific | 2019 |
| TA Power Solutions Limited | Professional & scientific | 2012 |
| Tamarisk (West Sussex) Management Company Limited | Extraterritorial | 2010 |
| Tamburello Limited | Administrative & support | 1994 |
| Tandoori Nights Rustington Ltd | Hospitality | 2018 |
| Tannery Gardens Residents Management Company Limited | Households | 2011 |
| Tansy's Dog Grooming Limited | Other services | 2024 |
| Tapp Recruit Ltd | Administrative & support | 2020 |
| Taraxakum Ltd | Health & social care | 2013 |
| Taste in Perfection Ltd | Information & communication | 2025 |
| Taylorgp Ltd | Arts & recreation | 2023 |
| Taylors Technical Services Limited | Administrative & support | 1986 |
| Tea Four Limited | Wholesale & retail | 2011 |
| TEC26 Limited | Information & communication | 2026 |
| Tech 2 WIN Competitions Ltd | Information & communication | 2024 |
| Techie Limited | Information & communication | 1996 |
| Techliu Limited | Information & communication | 2017 |
| Techron Equipment Limited | Wholesale & retail | 1993 |
| Tekky's Ltd | Wholesale & retail | 2019 |
| Telemerge IT Services UK Ltd | Information & communication | 2024 |
| Teloimport Ltd | Wholesale & retail | 2024 |
| Temps Dental Recruitment Ltd | Administrative & support | 2024 |
| TEN Eighty Limited | Real estate | 2002 |
| Tenant Management (4) Limited | Households | 2004 |
| Tendercare Limited | Manufacturing | 1998 |
| Teqsys Ltd | Information & communication | 2022 |
| TFB Consultants Ltd | Professional & scientific | 2014 |
| Thaggys Ltd | Other services | 2020 |
| THAHOST263 Limited | Arts & recreation | 2025 |
| That's SO Gemma Limited | Professional & scientific | 2022 |
| THE Anchor Springs Brewery Company Limited | Manufacturing | 2009 |
| THE Artis Crewe Ltd | Professional & scientific | 2020 |
| THE Arun Kitchen and Bathroom Company Ltd | Construction | 2026 |
| THE Back Office Collective Limited | Professional & scientific | 2025 |
| THE Bake LAB Ltd | Manufacturing | 2025 |
| THE Baytree Group Limited | Professional & scientific | 1993 |
| THE Beach Stop Ltd | Hospitality | 2025 |
| THE Bear Free House Limited | Hospitality | 2025 |
| THE Beeches (Dappers Lane) Residents Management Company Ltd | Households | 2020 |
| THE Bluebird Cafe Limited | Hospitality | 2002 |
| THE Boathouse in the Marina Limited | Hospitality | 2017 |
| THE Body Shop Amea Limited | Wholesale & retail | 2025 |
| THE Body Shop Brand Limited | Wholesale & retail | 2024 |
| THE Body Shop Holdings Limited | Wholesale & retail | 2024 |
| THE Body Shop International Limited | Wholesale & retail | 2024 |
| THE Bolton Bombshells Ltd | Information & communication | 2025 |