| I-Q Tyre Centre Limited | Wholesale & retail | 2020 |
| I.E.P. (Wholesale) Limited | Wholesale & retail | 2008 |
| I.J.L. Communications Limited | Information & communication | 2013 |
| I.M.N. Nutrition & Lifestyle Ltd | Other services | 2016 |
| I.S Group Holdings Ltd | Financial services | 2023 |
| I.S.A. Service Transformation Consultancy Ltd | Information & communication | 2023 |
| I.T.S. Plastering Ltd | Construction | 2015 |
| I10 Limited | Professional & scientific | 2004 |
| I3EC Electronic Security Limited | Administrative & support | 2017 |
| I3ERT Ltd | Transport & logistics | 2021 |
| I3MEDIA Ltd | Information & communication | 2009 |
| I4C Vending Ltd | Wholesale & retail | 2023 |
| IA Car Company Ltd | Wholesale & retail | 2020 |
| IA Lawal Limited | Financial services | 2024 |
| Ia&B Services Limited | Administrative & support | 2021 |
| IAB Wholesale Limited | Wholesale & retail | 2018 |
| Iain Toombs Services Limited | Information & communication | 2012 |
| Iakab Dent Ltd | Health & social care | 2009 |
| Iamtsg Limited | Information & communication | 2021 |
| IAN Ball Associates Limited | Professional & scientific | 2019 |
| IAN Barnett Limited | Professional & scientific | 2022 |
| IAN C Bradley Associates Ltd | Professional & scientific | 2010 |
| IAN Winters Consultancy Ltd | Professional & scientific | 2009 |
| Iannovate Limited | Information & communication | 2024 |
| IAR Asset Holdings Limited | Information & communication | 2026 |
| Iaza Limited | Real estate | 2024 |
| IB Automotive Ltd | Wholesale & retail | 2023 |
| IB Residential Limited | Real estate | 2024 |
| Ibacc Group Ltd | Professional & scientific | 2018 |
| Ibby Motors Ltd | Wholesale & retail | 2019 |
| Ibby Travels Solution Ltd | Transport & logistics | 2025 |
| Ibbytek Limited | Wholesale & retail | 2021 |
| Ibbyz Ltd | Wholesale & retail | 2024 |
| Ibex Carz Ltd | Transport & logistics | 2024 |
| Ibex Holdings Limited | Professional & scientific | 2003 |
| Ibizan Cocktails Ltd | Hospitality | 2023 |
| Ibpharm Ltd | Wholesale & retail | 2020 |
| Ibrahim Junaid Enterprises Ltd | Wholesale & retail | 2025 |
| Ibrahimi (Peterborough) Ltd | Administrative & support | 2016 |
| Ibrangefoods Limited | Wholesale & retail | 2024 |
| Ibta Ltd | Real estate | 2020 |
| IC Drivers Ltd | Transport & logistics | 2023 |
| IC Garage Ltd | Wholesale & retail | 2025 |
| IC Lighting Ltd | Construction | 2012 |
| IC Transport Ltd | Manufacturing | 2023 |
| Ice Cone LLP | | 2026 |
| Ice Cone Manufakture Ltd | Manufacturing | 2023 |
| Ice Sports Ltd | Wholesale & retail | 2025 |
| Iceberg Global Education Ltd | Professional & scientific | 2021 |
| Ichrc Ltd | Information & communication | 2023 |
| Iclinical Ltd | Health & social care | 2021 |
| ICM Refrigeration Services Ltd | Administrative & support | 2006 |
| ICM RS Trustee Ltd | Administrative & support | 2023 |
| Icmusicmedia Ltd | Arts & recreation | 2023 |
| ICN Delivery Ltd | Transport & logistics | 2020 |
| Icon Peterborough Ltd | Education | 2015 |
| Icon Pro Builders Ltd | Construction | 2024 |
| Iconic Edge Ltd | Wholesale & retail | 2025 |
| Iconic Mane Limited | Wholesale & retail | 2024 |
| Iconic Surveyors Limited | Professional & scientific | 2025 |
| Iconshift Ltd | Information & communication | 2025 |
| ICP Press Limited | | 1987 |
| Icsynergy Ltd. | Construction | 2013 |
| ICY SIP Ltd | Wholesale & retail | 2025 |
| ID Theft Protect Limited | Information & communication | 2005 |
| Id-A Protect Limited | Information & communication | 2007 |
| Idaho Music Limited | Information & communication | 2013 |
| Idea Hair and Beauty Ltd | Other services | 2017 |
| Idea Project Ltd | Wholesale & retail | 2019 |
| Idea Studio MMA Limited | Information & communication | 2006 |
| Idea-Innovations Limited | Professional & scientific | 2012 |
| Ideal Business Solutions Limited | Administrative & support | 2022 |
| Ideal Driving School Peterborough Limited | Education | 2025 |
| Ideal Hair & Beauty Supplies Ltd | Wholesale & retail | 1978 |
| Ideal Lettings (Peterborough) Ltd | Households | 2025 |
| Ideal Power Holdings Limited | Financial services | 2015 |
| Ideal Power Limited | Wholesale & retail | 2000 |
| Ideal Prestige Properties Limited | Construction | 2003 |
| Ideal Property Facilities Limited | Construction | 2018 |
| Ideal Resource Limited | Information & communication | 2012 |
| Ideal Social Care Group Ltd | Public administration | 2023 |
| Identity Management Technologies Limited | Information & communication | 2011 |
| Ideq Capital Ltd | Financial services | 2021 |
| Idevnerds Ltd | Information & communication | 2023 |
| IDF Constructions Ltd | Construction | 2018 |
| IDL Electrical Limited | Construction | 2010 |
| IDM Interiors Ltd | Construction | 2023 |
| IDM Pro Trans Ltd | Transport & logistics | 2016 |
| IDO Cloudtech Ltd | Information & communication | 2019 |
| IDO Property Ltd | Real estate | 2018 |
| Idream Entertainment Ltd | Arts & recreation | 2013 |
| Idris Properties Ltd | Construction | 2021 |
| Idris Property Ltd | Construction | 2021 |
| Idriseb Trans Ltd | Transport & logistics | 2019 |
| Idrive Limited | Wholesale & retail | 2021 |
| Idrive Motor Group UK Limited | Wholesale & retail | 2023 |
| IEDUC8 Ltd | Real estate | 2018 |
| IFC Drainage Limited | Water & waste | 2024 |
| Ifeewunata Company Limited | Construction | 2021 |
| IFH Limited | Other services | 2026 |