| SHO Housing Ltd | Real estate | 2025 |
| Shoaib Flooring Ltd | Construction | 2023 |
| Shoemaster Rochdale Ltd | Other services | 2018 |
| Shop 360 Ltd | Wholesale & retail | 2021 |
| SHOP4EVRY1 Ltd | Wholesale & retail | 2024 |
| Shopgooduk Ltd | Wholesale & retail | 2024 |
| Shoponweb Limited | Manufacturing | 2026 |
| Shoppocracy Ltd | Wholesale & retail | 2024 |
| SHOPZY0.LTD Ltd | Wholesale & retail | 2025 |
| Shopzzy Limited | Wholesale & retail | 2025 |
| Shore Aviation Ltd | Professional & scientific | 2023 |
| Shore Motor Company Ltd | Wholesale & retail | 2026 |
| Shoreham Street Limited | Real estate | 2024 |
| Shotgunmike Audio Ltd | Information & communication | 2019 |
| Shredential Limited | Extraterritorial | 2015 |
| Shruthi Limited | Health & social care | 2014 |
| Shtubi Holdings Ltd | Financial services | 2024 |
| Shubh Logistics Ltd | Transport & logistics | 2025 |
| Shunaar Bangladesh Ltd | Hospitality | 2026 |
| Sialkot Food Jungle Ltd | Hospitality | 2022 |
| Sialvi Trans Limited | Transport & logistics | 2021 |
| Siddhi Overseas UK Ltd | Wholesale & retail | 2021 |
| Siddiq Textile Limited | Manufacturing | 2022 |
| Siddique Solicitors Limited | Professional & scientific | 2020 |
| Side Street Properties Ltd | Real estate | 2021 |
| Sidney and Sapphire Limited | Wholesale & retail | 2020 |
| Siempre Security Limited | Administrative & support | 2017 |
| Sign in Convenience Store Limited | Wholesale & retail | 2017 |
| Sign IT UP Ltd | Manufacturing | 2024 |
| Signature Construction Developments Limited | Construction | 2013 |
| Signature Medical Birmingham Limited | Health & social care | 2021 |
| Signature Medical Cardiff Limited | Health & social care | 2021 |
| Signature Medical London Limited | Health & social care | 2021 |
| Signature Medical Manchester Limited | Health & social care | 2021 |
| Signature Medical Topco Limited | Financial services | 2023 |
| Signature Outdoor Living Ltd | Administrative & support | 2024 |
| Sigsum Ltd | Wholesale & retail | 2025 |
| SIH Foods Ltd | Hospitality | 2024 |
| Sika Solar Ltd | Professional & scientific | 2024 |
| Sila&Azaan Foods Limited | Hospitality | 2025 |
| Silco Online Limited | Wholesale & retail | 2019 |
| Silco Star Limited | Wholesale & retail | 2018 |
| Silk Thread Ltd | Wholesale & retail | 2025 |
| Silverback Pharma Limited | Wholesale & retail | 2018 |
| Silvergate Estates Ltd | Real estate | 2025 |
| Silviculture Limited | Administrative & support | 2014 |
| Silyk Limited | Hospitality | 2024 |
| SIM Switchgear Aberdeen Limited | Construction | 2019 |
| SIM Switchgear Holdings Limited | Construction | 2022 |
| SIM Switchgear Limited | Construction | 2003 |
| Simkat Shore Holdings Ltd | Real estate | 2017 |
| Simkiss Holding (SHA) Limited | Financial services | 2022 |
| Simkiss Home Automation Limited | Wholesale & retail | 1973 |
| Simkiss Limited | Real estate | 2002 |
| Simon & Simon Security Limited | Professional & scientific | 1999 |
| Simon Mccormack Plumbing & Heating Ltd | Construction | 2019 |
| Simons & Holden LLP | | 2021 |
| Simple a Mastic Ltd | Construction | 2019 |
| Simplex Ideas Ltd | Wholesale & retail | 2024 |
| Simply Affordable Properties Ltd | Real estate | 2017 |
| Simply Health Ltd | Health & social care | 2023 |
| Simply Indian Lounge Ltd | Hospitality | 2017 |
| Simply ME Ltd | Wholesale & retail | 2026 |
| Simply Medico Limited | Other services | 2020 |
| Simply Properties (Rochdale) Limited | Real estate | 2013 |
| Simtek (UK) Ltd. | Manufacturing | 2006 |
| Simulous Food Consultancy Ltd | Hospitality | 2024 |
| Simzanite Limited | Wholesale & retail | 2019 |
| Sincity Ltd | Hospitality | 2022 |
| Sinead Fitness Ltd | Arts & recreation | 2025 |
| Singhar Beauty NW Ltd | Health & social care | 2023 |
| Singhar Yorkshire Ltd | Health & social care | 2024 |
| Sinmar Plant Operations Ltd | Administrative & support | 2016 |
| Sino Chemsource Ltd | Administrative & support | 2017 |
| Sinowest Ltd | Wholesale & retail | 2026 |
| Sioharesolutions Ltd | Professional & scientific | 2026 |
| Siren Healthcare Ltd | Wholesale & retail | 2026 |
| Site Security Northwest Ltd | Administrative & support | 2017 |
| Sitehelpdesk.Com Limited | Information & communication | 2000 |
| SIW House Limited | Real estate | 2026 |
| SIX Sigma Motors Limited | Wholesale & retail | 2024 |
| Sixth Property Co. Limited | Construction | 1993 |
| Sizie Private Ltd | Information & communication | 2024 |
| Sizy Limited | Wholesale & retail | 2025 |
| Sizzling Pizza and Kebab Ltd | Hospitality | 2025 |
| Siân Alexia Ltd | Arts & recreation | 2021 |
| SJ Capital Group Ltd | Professional & scientific | 2026 |
| SJ Delivery Solutions Ltd | Transport & logistics | 2021 |
| SJ Electrical Services Ltd | Construction | 2025 |
| SJ Heald Limited | Education | 2009 |
| SJ Motors Group Ltd | Wholesale & retail | 2026 |
| SJ Phillips Properties Ltd | Real estate | 2025 |
| SJ Roofing Services Limited | Construction | 2013 |
| SJA Electrical & Sons Ltd. | Construction | 2018 |
| Sjan Properties Limited | Real estate | 2026 |
| SJF Granite & Quartz Ltd | Manufacturing | 2023 |
| SJG Aviation Services Ltd | Transport & logistics | 2025 |
| SJH Trading Ltd | Wholesale & retail | 2019 |
| SJJ UK Trading Ltd | Hospitality | 2023 |
| SJM Clinical Services Ltd | Health & social care | 2025 |