| C&R Removals and Storage Limited | Other services | 2014 |
| C.A.R. & J.M. Stubbs Ltd | Agriculture & fishing | 2016 |
| C.H.A.S.E (Create Hope and Safe Environments) C.I.C. | Education | 2024 |
| Cadwell Motorcycles Ltd | Wholesale & retail | 2023 |
| CAG Driveways Ltd | Construction | 2019 |
| Cambridge Mineral Resources PLC | Professional & scientific | 1988 |
| Cannon Trading Limited | Construction | 2014 |
| Canon Independent Mortgage Services Ltd | Financial services | 2023 |
| Capillum Limited | Other services | 2003 |
| Car-Very Drive Thru Limited | Hospitality | 2024 |
| Cardinals Lincoln Limited | Extraterritorial | 2025 |
| Carlton Cleaning (UK) Limited | Administrative & support | 2006 |
| Carlton Cleaning Holdings Ltd | Real estate | 2021 |
| Carlton Hygiene Specialists Ltd | Administrative & support | 2024 |
| Carlton Park (Manby) Management Limited | Households | 1987 |
| Carlton Renewable Energy Limited | Real estate | 2012 |
| Carlton Road Management Company Limited | Households | 2017 |
| Cartledge Timber Frame Limited | Construction | 2009 |
| Castle Tree Care Limited | Agriculture & fishing | 2015 |
| Cat Electrical Limited | Construction | 2023 |
| Cawmc Restoration and Auto Refinishers Limited | Wholesale & retail | 2016 |
| CBH Build Ltd | Construction | 2006 |
| CF Trustees Limited | Professional & scientific | 2018 |
| CGC Ecology Limited | Professional & scientific | 2020 |
| Chambers Commercial Ltd | Real estate | 2020 |
| Charterhouse Farming Limited | Agriculture & fishing | 2025 |
| Cheaper Business Group Ltd | Administrative & support | 2025 |
| Cheaper Business Services (Lincolnshire) Limited | Administrative & support | 2018 |
| Cheaper Business UK Ltd | Information & communication | 2021 |
| Cheapside Investment Co.Limited | Construction | 1959 |
| Checkmate Productions Ltd | Administrative & support | 2025 |
| Cheekychimpcity Ltd | Information & communication | 2015 |
| Chopper Cost Mesi Ltd | Wholesale & retail | 2020 |
| Chris Vertigan Limited | Health & social care | 2014 |
| Chris Williams Electrical Ltd | Construction | 2012 |
| Chris Worth Productions Ltd | Arts & recreation | 2015 |
| Christy's Collectables Ltd | Wholesale & retail | 2024 |
| Churchills of North Somercotes Limited | Wholesale & retail | 2023 |
| City & Commercial Services Ltd | Administrative & support | 2022 |
| Cj's Metals Ltd | Wholesale & retail | 2026 |
| CJC Fabrications Limited | Manufacturing | 2021 |
| CJP Digital Limited | Information & communication | 2016 |
| Clandestine Digital Limited | Information & communication | 2025 |
| Clarity Therapy Ltd | Health & social care | 2025 |
| Clason Enterprizes Limited | Hospitality | 2005 |
| Classical Music Licensing Ltd | Arts & recreation | 2015 |
| Clavell (UK) Limited | Transport & logistics | 2004 |
| Clavell Caravans and Transport Limited | Wholesale & retail | 2005 |
| Claylake Rural Retreat Ltd | Hospitality | 2023 |
| Clee House Limited | Hospitality | 1999 |
| Clements Court Limited | Administrative & support | 1998 |
| Clough Build Limited | Construction | 2023 |
| Clunkett Software Limited | Information & communication | 2026 |
| CMA Interim Ltd | Information & communication | 2018 |
| Cocoa Encounters Ltd | Hospitality | 2018 |
| Coded Armour Limited | Information & communication | 2021 |
| Coladain Solutions Ltd | Manufacturing | 2026 |
| Coleman Plastering Limited | Construction | 2005 |
| Coloured Marble Limited | Professional & scientific | 1971 |
| Commercial Mushroom Growers UK Ltd | Agriculture & fishing | 2019 |
| Communicology Ltd | Information & communication | 2021 |
| Community Healthcare Ltd | Health & social care | 2018 |
| Coney's Warrens Limited | Real estate | 2024 |
| Conic Property Limited | Households | 2025 |
| Conisholme Farms (Holdings) Limited | Extraterritorial | 1988 |
| Conisholme Farms Limited | Agriculture & fishing | 1960 |
| Conon Properties Limited | Hospitality | 2004 |
| Cookstown Asset Management Unlimited Company | | 2024 |
| Coolbox Refrigerated Trailer Hire Ltd | Administrative & support | 2024 |
| Cooler Castle Limited | Wholesale & retail | 2015 |
| Cooper Press Ltd. | Information & communication | 2011 |
| Corix Research Labs UK Limited | Manufacturing | 2023 |
| Corrosol Global Ltd | Professional & scientific | 2025 |
| Cosmic Spirits Ltd | Wholesale & retail | 2025 |
| Cosmokorix Holdings Limited | Financial services | 2021 |
| Countrywide Business Transfer Consultants Limited | Extraterritorial | 1989 |
| Couplands (Lincoln) Limited | Wholesale & retail | 1994 |
| Couplands (Louth) Limited | Wholesale & retail | 2005 |
| Couplands (Worksop) Limited | Wholesale & retail | 2024 |
| Court Maisonettes Limited | Households | 1959 |
| Covenham Investments Limited | Real estate | 2011 |
| Crafty Bunch Beer Ltd | Hospitality | 2024 |
| Crafty Bunch PUB Company Ltd | Hospitality | 2022 |
| Craig Collinson Limited | Other services | 2008 |
| Craig Evans Plumbing Limited | Construction | 2003 |
| Craig Papper Plumbing and Heating Limited | Construction | 2018 |
| Creative Heights Lincs CIC | Education | 2025 |
| Crown Mills (Louth) Limited | Households | 2015 |
| Crystal Harmony Ltd | Wholesale & retail | 2023 |
| Cullingford Way Management Limited | Households | 2022 |
| Curtis Wealth Management Ltd. | Professional & scientific | 2013 |
| Cutting Edge Garden Services Limited | Other services | 2017 |
| CW Chiropractic Ltd | Health & social care | 2023 |
| D R Harrison Ltd | Education | 2002 |
| D R Jobe Limited | Financial services | 2023 |
| D Robinson Consulting Ltd | Hospitality | 2024 |
| D Salkeld Limited | Administrative & support | 2003 |
| D. Haxby Farms Limited | Agriculture & fishing | 1977 |
| D.& D. Engineering (Lincs.) Limited | Manufacturing | 1994 |
| D.A & P Spindley Property Holding's Ltd | Real estate | 1996 |