| C&R Care Ltd | Health & social care | 2025 |
| Caats Investments Limited | Professional & scientific | 2022 |
| Caddow Wood Forestry and Farming Ltd | Agriculture & fishing | 2026 |
| Cade Lane Management Company Limited | Professional & scientific | 2003 |
| Cadence Ventures Ltd | Professional & scientific | 2026 |
| Cadsbell Properties Ltd | Real estate | 2025 |
| Caenby Corner Estate Limited | Real estate | 1985 |
| Cake Traders Ltd | Wholesale & retail | 2019 |
| Cakery Bakery Corner Ltd | Wholesale & retail | 2023 |
| CAL Developments (Lincs) Ltd | Construction | 2017 |
| Callum Redhead Construction Ltd | Construction | 2024 |
| CAM Coffee Ltd | Hospitality | 2023 |
| Campus for Future Living Limited | Real estate | 2024 |
| Candy Machinery Limited | Manufacturing | 2013 |
| Canute Leisure Ltd | Hospitality | 2025 |
| Car Parking Management UK Ltd | Manufacturing | 2021 |
| Carly Smith Property Limited | Real estate | 2023 |
| Carmichael Property Group Limited | Professional & scientific | 2019 |
| Carrow Medical Limited | Health & social care | 2010 |
| Cart’Any Ltd | Other services | 2025 |
| Casper Property Limited | Households | 2018 |
| Castlegate House Rest Home Limited | Health & social care | 1984 |
| Cat Care Services Ltd | Professional & scientific | 2026 |
| Cater Gray Limited | Professional & scientific | 2013 |
| Cats & Co Limited | Manufacturing | 2014 |
| Cauvin Ltd | Transport & logistics | 2015 |
| CB Design and Development Limited | Information & communication | 2018 |
| CBN Electrical Services Ltd | Construction | 2017 |
| CCB Property Limited | Real estate | 2026 |
| CCS Online Limited | Wholesale & retail | 2014 |
| CDL Rental Property Limited | Real estate | 2009 |
| Cedar Rose Homes Ltd | Health & social care | 2025 |
| Centrepoint Kitchens Ltd | Manufacturing | 2024 |
| Cerakote by PB Ltd | Construction | 2021 |
| Ceramex Ltd | Manufacturing | 2004 |
| CFC Trans Ltd | Financial services | 2020 |
| CFS Ciano Fitting Services Ltd | Construction | 2022 |
| Challoner Building Services Limited | Construction | 2019 |
| Challoner Transport Limited | Transport & logistics | 2021 |
| Changing Waste Ltd | Water & waste | 2016 |
| Chantry Agricultural Sales Ltd | Wholesale & retail | 2020 |
| Charge Wise Ltd | Construction | 2020 |
| Charlesworth Health, Safety and Environment Ltd | Professional & scientific | 2011 |
| CHASE10 Limited | Construction | 2026 |
| Cheesy Monkey Ltd | Hospitality | 2024 |
| Chef Chen Limited | Hospitality | 2025 |
| Ches Capital Group Ltd | Information & communication | 2025 |
| Chic of Gainsborough Limited | Water & waste | 2012 |
| Chlomee Ltd | Hospitality | 2024 |
| Chorus Furniture Limited | Wholesale & retail | 2011 |
| Chris the Mindset Coach CIC | Health & social care | 2024 |
| Christopher J. Day Limited | Agriculture & fishing | 1984 |
| Church of the Forgiving Eagle Ltd | Wholesale & retail | 2025 |
| Cicon Holdings Ltd | Real estate | 2025 |
| Citizens Advice Lincoln & Lindsey | Information & communication | 2003 |
| CJ & B Parr & Sons Limited | Agriculture & fishing | 2011 |
| CJ Property (Lincoln) Ltd | Other services | 2022 |
| CJH Consultancy Limited | Professional & scientific | 2015 |
| CJR Maintenance Solutions Limited | Administrative & support | 2012 |
| CJS Developments Ltd | Construction | 2023 |
| CJS Plumbing Heating & Mechanical Services Ltd | Construction | 2018 |
| Clare Chardoux Limited | Hospitality | 2024 |
| Clayden Construction Limited | Construction | 2011 |
| Clayton Industrial Services Limited | Transport & logistics | 2006 |
| Clayton Joinery Limited | Construction | 2019 |
| Clean and Retrieve Limited | Construction | 2002 |
| Clements Plant Ltd | Wholesale & retail | 2011 |
| Client Side Ltd | Arts & recreation | 2022 |
| Cliff Bradley Memorials Limited | Other services | 2024 |
| Climate Control Limited | Construction | 1996 |
| Clinical and Education Solutions Ltd | Education | 2018 |
| Clint Holdings Ltd | Real estate | 2024 |
| Clock House Gainsborough Limited | Hospitality | 2026 |
| Cloverdale Ltd | Professional & scientific | 2017 |
| CLR Investment Properties Ltd | Real estate | 2021 |
| Club Gainsborough CIC | Education | 2025 |
| Clugston Holdings Limited | Financial services | 2024 |
| Clugston International Trading Limited | Transport & logistics | 2016 |
| CMP Promotions Ltd | Arts & recreation | 2003 |
| CNW Solutions Limited | Other services | 2021 |
| Coached by Conway Ltd | Arts & recreation | 2026 |
| Cochrane Capital | Financial services | 2024 |
| COE & Co Fine Jewellery Limited | Wholesale & retail | 2007 |
| Cogito Resolutions Limited | Professional & scientific | 2026 |
| Col's Mere Limited | Hospitality | 2019 |
| Collective Care and Support Limited | Health & social care | 2023 |
| Collective Dimensions Limited | Health & social care | 2024 |
| Collective Pathways Limited | Financial services | 2025 |
| Collision Assist Solutions Ltd | Wholesale & retail | 2022 |
| Combat Zone Events Limited | Arts & recreation | 2018 |
| Communi-Rate Limited | Information & communication | 2022 |
| Community Learning in Partnership Limited | Education | 2009 |
| Company 89 Ltd | Wholesale & retail | 2025 |
| Compart (Humberside) Limited | Wholesale & retail | 1993 |
| Competency Co Limited | Health & social care | 2023 |
| Completeair (UK) Ltd | Energy | 2020 |
| Connamix Ltd | Information & communication | 2018 |
| Connectors Limited | Administrative & support | 1974 |
| Construction Training Assessments Ltd | Construction | 2015 |
| Control Plan Ltd | Manufacturing | 2024 |