| Cardea Healthcare-Northants Ltd | Administrative & support | 2024 |
| Cardell Rigging Services Ltd | Information & communication | 2017 |
| Cardesa Aesthetics International Ltd | Other services | 2023 |
| Cardinal IT Solutions Limited | Information & communication | 2010 |
| Cardinalco Ltd | Professional & scientific | 2024 |
| Cards and Roses Ltd | Wholesale & retail | 2022 |
| Care 365 Plus Limited | Health & social care | 2024 |
| Care Comply Solutions Ltd | Public administration | 2023 |
| Care Connect Services Ltd | Administrative & support | 2025 |
| Care Connect Software Ltd | Information & communication | 2023 |
| Care Cover Solutions Limited | Health & social care | 2015 |
| Care Difference Limited | Health & social care | 2015 |
| Care Launch Limited | Professional & scientific | 2024 |
| Care Prism Limited | Wholesale & retail | 2021 |
| Care-Excel Ltd | Administrative & support | 2015 |
| CARE4LIFEHEALTHCARE Services Ltd | Health & social care | 2017 |
| Carebank Healthcare Limited | Administrative & support | 2012 |
| Caredom Healthcare Limited | Health & social care | 2019 |
| Careers Consult UK Ltd | Education | 2022 |
| Careers Medical Ltd | Health & social care | 2018 |
| Careguru Recruitment Ltd | Administrative & support | 2017 |
| Carehome.Org.Uk Limited | Hospitality | 2000 |
| Carelink Northants CIC | Transport & logistics | 2026 |
| Carene Properties LLP | | 2016 |
| Carepable Ltd | Administrative & support | 2023 |
| Careuk Living Ltd | Health & social care | 2021 |
| Carewell 24 Care Services Ltd | Health & social care | 2025 |
| Cargo 28 Limited | Transport & logistics | 2017 |
| Cargoes Limited | Transport & logistics | 2003 |
| Cargoprime Ltd | Transport & logistics | 2020 |
| Caribbean Jerk Limited | Hospitality | 2018 |
| Carina Transport Ltd | Transport & logistics | 2024 |
| Caring Hearts Support CIC | Health & social care | 2025 |
| Caring Neighbour Limited | Health & social care | 2021 |
| Caringhearts Healthcare Services Limited | Health & social care | 2023 |
| Carisbrooke Mews Management Company Limited | Other services | 1996 |
| Carla Services Ltd | Transport & logistics | 2025 |
| Carlinks Healthcare Ltd | Administrative & support | 2020 |
| Carlos & Europe Security Ltd | Other services | 2018 |
| Carlos Europe Investments Limited | Real estate | 2019 |
| Carlos Europe Recruitment Ltd | Administrative & support | 2013 |
| Carlos Europe Security Limited | Administrative & support | 2009 |
| Carlos Remes Limited | Manufacturing | 1973 |
| Carly Cleaning Services Ltd | Administrative & support | 2021 |
| Carmac Building Products Ltd. | Wholesale & retail | 2008 |
| Carmangeria J&S Butchers Limited | Wholesale & retail | 2025 |
| Carmel CT Management Company Limited | Households | 2015 |
| Carmel Property Developments Limited | Construction | 2017 |
| Carmeltime Limited | Professional & scientific | 1986 |
| Carmine Estates Limited | Construction | 2018 |
| Caro Developments Ltd | Real estate | 2023 |
| Carolchaps Healthcare Limited | Health & social care | 2015 |
| Caroline Sinclair Ltd | Other services | 2026 |
| Carolkate Limited | Health & social care | 2018 |
| Carpatica Romanian Shop Ltd | Wholesale & retail | 2014 |
| Carpe Investments Ltd | Construction | 2014 |
| Carpe Ventures Ltd | Construction | 2019 |
| Carpets Northampton Limited | Wholesale & retail | 2003 |
| Carpettt. Ltd | Construction | 2024 |
| Carpit Ltd | Wholesale & retail | 2026 |
| Carranca Limited | Professional & scientific | 2021 |
| Carrem Cleaning Ltd | Administrative & support | 2023 |
| Carriage Properties Limited | Construction | 2017 |
| Carrino Flooring Limited | Construction | 1994 |
| Carrino Holdings Limited | Professional & scientific | 2018 |
| Carro Group Ltd | Administrative & support | 2025 |
| Carro Recruitment Limited | Administrative & support | 2022 |
| Carro Transport Ltd | Transport & logistics | 2020 |
| Carry-On Products Ltd | Manufacturing | 2012 |
| Cars&Parts Ltd | Wholesale & retail | 2022 |
| Cart Way Ltd | Wholesale & retail | 2025 |
| Cartel Brasserie & Grill Ltd | Hospitality | 2026 |
| Carter Horsley (Tyres) Limited | Wholesale & retail | 1978 |
| Carter SBM Limited | Construction | 2008 |
| Carteros.Msv Limited | Transport & logistics | 2021 |
| Cartify Online Ltd | Wholesale & retail | 2025 |
| Carton Edge Limited | Manufacturing | 1991 |
| Carver/Wright Limited | Construction | 2011 |
| Cas-Sell CVA Limited | Wholesale & retail | 1983 |
| Casa Sabrosa Limited | Hospitality | 2023 |
| Casa SIX Ltd | Professional & scientific | 2025 |
| Caschiropractic Ltd | Health & social care | 2011 |
| Case Building Services Maintenance Ltd | Construction | 2005 |
| Case Electrical Ltd | Construction | 2002 |
| Case Farm Construction Ltd | Construction | 2017 |
| Case Holdings Ltd | Financial services | 2022 |
| Cash Connect Limited | Financial services | 2025 |
| Casi International Limited | | 1997 |
| Casper & Davis Ltd | Education | 2023 |
| Casper Davis Limited | Other services | 2015 |
| Casper's Snack Wagon Limited | Wholesale & retail | 2019 |
| Caspian Warehousing and Logistics Ltd | Transport & logistics | 2021 |
| Cass - Compliance and Advisory Safety Services Ltd. | Professional & scientific | 2020 |
| Cass London Ltd | Wholesale & retail | 2026 |
| Cassmax Limited | Manufacturing | 2025 |
| Cassyannes Ltd | Other services | 2026 |
| Cast Group International Limited | Professional & scientific | 2021 |
| Castile Court (Waltham Cross) Management Company Limited | Professional & scientific | 1990 |
| Castilian Investments Limited | Real estate | 2010 |
| Castilian Property Management Company Limited | Real estate | 2015 |