| College Street Technical Services CIC | Arts & recreation | 2021 |
| Collett Payroll Services Ltd | Administrative & support | 2006 |
| Colligant Limited | Administrative & support | 2013 |
| Collinge Associates Ltd | Construction | 2026 |
| Collingham Plumbing and Heating Limited | Construction | 2023 |
| Collington Holdings Limited | Financial services | 2020 |
| Collins Realty Ltd | Construction | 2025 |
| Collins Training Limited | Other services | 2013 |
| Collinshallgreen Limited | Professional & scientific | 2015 |
| Collishaw Paraplanning & Support Services Limited | Administrative & support | 2024 |
| Collyer Consultancy Services Limited | Manufacturing | 2019 |
| Collymore Estates Limited | Real estate | 2024 |
| Cololas Ltd | Administrative & support | 2016 |
| Color Brands UK Limited | Hospitality | 2015 |
| Colorset Inc. Limited | Professional & scientific | 2013 |
| Colour Command & Combat Ltd | Manufacturing | 2020 |
| Colour Flux Limited | Manufacturing | 2025 |
| Colour Inspiration by Park Ltd | Wholesale & retail | 2024 |
| Colour Stone Catering Ltd | Manufacturing | 2024 |
| Coloured Linen Hire Limited | Other services | 2021 |
| Colourful Blinds Ltd | Wholesale & retail | 2021 |
| Coloursafe Limited | Professional & scientific | 2014 |
| Colsmen Limited | Information & communication | 2011 |
| Colspar Asbestos Services Limited | Construction | 2008 |
| Colspar Environmental Services Limited | Construction | 2005 |
| Colsterworth Pallets Ltd | Wholesale & retail | 2014 |
| Colston Bassett Hall Stable Block Development Limited | Households | 1980 |
| Coltman Holdings Limited | Financial services | 2020 |
| Columa Water Limited | Water & waste | 2013 |
| Columbus Global UK Ltd | Information & communication | 1994 |
| Colway Computers Limited | Information & communication | 1994 |
| Colwick Business Park Management Company Limited | Households | 2003 |
| Colwick Cafe Ltd | Hospitality | 2026 |
| Colwick Couriers Ltd | Transport & logistics | 2023 |
| Colwick Electrical Solutions Ltd | Construction | 2012 |
| Colwick Park Management Limited | Real estate | 1982 |
| Colwick Property Ltd | Construction | 2015 |
| Colwick Road Garage Ltd | Wholesale & retail | 2003 |
| Coly Investments Limited | Financial services | 1992 |
| Comabe Engineering Research and Development Ltd | Professional & scientific | 2026 |
| Comax Construction Ltd | Construction | 2020 |
| Combat Health Limited | Education | 2013 |
| Combellack Construction Limited | Construction | 2025 |
| Combellack Holdings Limited | Construction | 2005 |
| Combellack Limited | Construction | 2013 |
| Combellack Properties Limited | Real estate | 2005 |
| Combi Ride Ltd | Administrative & support | 2008 |
| Combine Fabs Ltd | Manufacturing | 2011 |
| Combine Group Limited | Administrative & support | 2022 |
| Comcat Electrical Limited | Manufacturing | 2019 |
| Come & Plumb IT Limited | Construction | 2014 |
| Comer Industries (UK) Ltd | Wholesale & retail | 1988 |
| Comet SPV 1 Limited | Administrative & support | 2024 |
| Cometa Scientific Limited | Wholesale & retail | 2001 |
| Comfinity Limited | Information & communication | 2017 |
| Comfort Call Limited | Health & social care | 2006 |
| Comfort Call Services Ltd | Professional & scientific | 2019 |
| Comfort Care Direct Limited | Health & social care | 2025 |
| Comfort Circle Limited | Information & communication | 2026 |
| Comfort Estate Agents Ltd | Extraterritorial | 2019 |
| Comfort Hospitality UK Limited | Hospitality | 2025 |
| Comfort Letting Agents LLP | | 2011 |
| Comfort Nest Ltd | Health & social care | 2025 |
| Comfort Projects Ltd | Real estate | 2019 |
| Comfort Quality Care UK Ltd | Health & social care | 2022 |
| Comfort Rise Property Management Ltd | Real estate | 2025 |
| Comfort Short Stays Ltd | Extraterritorial | 2019 |
| Comfortable Duck Ltd | Wholesale & retail | 2025 |
| Comfortable IT Ltd | Wholesale & retail | 2025 |
| Comfy Garden Ltd | Wholesale & retail | 2024 |
| Coming Home Lettings Limited | Real estate | 2023 |
| Commando Locksmiths Ltd | Manufacturing | 2024 |
| Commerce Link (EU) Ltd | Professional & scientific | 2014 |
| Commercial Aviation Solutions Limited | Professional & scientific | 2022 |
| Commercial Consult Services Ltd | Professional & scientific | 2024 |
| Commercial Driver Hire Ltd | Transport & logistics | 2014 |
| Commercial Electrical Limited | Construction | 2017 |
| Commercial Furniture Company (UK) Limited | Manufacturing | 2025 |
| Commercial Inn Ltd | Hospitality | 2020 |
| Commercial IT Recycling Ltd | Water & waste | 2017 |
| Commercial Property Agents Limited | Real estate | 2021 |
| Commercial Store Development Ltd | Real estate | 2021 |
| Commercial Training Company Ltd | Construction | 2023 |
| Commify Limited | Financial services | 2016 |
| Commify Topco 2023 Limited | Financial services | 2022 |
| Commify Topco Limited | Financial services | 2016 |
| Commify UK Limited | Information & communication | 2001 |
| Commodity Creations Ltd | Water & waste | 2017 |
| Commodore Automatic Vending Machines Limited | Real estate | 1976 |
| Commodore Court (Nottingham) Ltd | Households | 2026 |
| Commodore Court Ltd | Households | 2020 |
| Common Excellence Ltd | Education | 2024 |
| Commonality Studios Limited | Administrative & support | 2022 |
| Commonwealth Residential Ltd | Real estate | 2024 |
| Communication,Hope and Trust (Chat ) CIC | Hospitality | 2022 |
| Communications 4 Results Limited | Administrative & support | 2013 |
| Communities That Work Ltd | Other services | 2015 |
| Community and Business Support UK Ltd | Administrative & support | 2021 |
| Community Café at ST Aidan's CIC | Hospitality | 2022 |
| Community CARE4U Limited | Health & social care | 2023 |