| inktec europe | witney | A rating |
| Inmarkets Ltd T/A Skillcast | London | A rating |
| Inmarsat Global Limited | London | A rating |
| InMindful (UK) Limited | London | A rating |
| InMobi | London | A rating |
| Inn on the Park (London) Limited doing business as Four Seasons Hotel London | London | A rating |
| INNOCEAN WORLDWIDE UK LTD | London | A rating |
| Innomotics Motors and Large Drives Limited | Salford | A rating |
| Innospec Limited | Ellesmere Port | A rating |
| Innovation Technology and Business Solutions Limited | London | A rating |
| Innovent Leasing Limited | London | A rating |
| Innovia Group (Holding 3) Ltd | Wigton | A rating |
| Innovis Consulting Limited | London | A rating |
| Innovo Holding Limited | London | A rating |
| Inoapps Ltd | Aberdeen | A rating |
| INOVAANTAGE LTD | Reading | A rating |
| Inovia Capital (UK) Limited | London | A rating |
| Inoxilos UK Ltd. | London | A rating |
| INPEX Europe Limited | London | A rating |
| Inserta Ltd | London | A rating |
| Insider Services UK Limited | London | A rating |
| InsideSource EMEA Limited | London | A rating |
| Insight Analytics Solutions Limited | Nottingham | A rating |
| Insight Direct (UK) Ltd | Sheffield | A rating |
| Insight Venture Management UK Limited | London | A rating |
| Insmed Innovation UK Ltd | Cambridge | A rating |
| Inspectorate International Ltd | Witham | A rating |
| Inspired Gaming (UK) Limited | Burton on Trent | A rating |
| InspireXT Consulting Ltd | London | A rating |
| Instem Ltd | Stone | A rating |
| Instil Bio (UK) Limited | Manchester | A rating |
| Instinet Global Services Limited | London | A rating |
| Institutional Limited Partners Association (UK) Limited | London | A rating |
| Institutional Shareholder Services UK Limited | London | A rating |
| Institutional Venture Partners UK LLP | Fitzorvia London | A rating |
| Instro Precision Ltd | Sandwich | A rating |
| Instron - Division of ITW Ltd | High Wycombe | A rating |
| Instructure Global Limited | London | A rating |
| Insulation Global Solutions Ltd | London | A rating |
| Insulet International Limited | London | A rating |
| Insure and Go Insurance Services Limited | Bristol | A rating |
| InsureMO (UK) Limited | London | A rating |
| Insurity Europe Ltd | London | A rating |
| Insync Bikes LIimited | Manchester | A rating |
| Intapp Limited | London | A rating |
| Intech Scaffolding Ltd | London | A rating |
| INTEGRA SOFTWARE SERVICES PRIVATE LTD | Berkshire | A rating |
| Integral Ad Science UK Limited | London | A rating |
| Integral Development Corporation (Europe) Limited | London | A rating |
| Integral Powertrain Ltd (trading as helix) | MILTON KEYNES | A rating |
| Integral Zone UK Limited | Reading | A rating |
| Integrated Clinical Oncology Network UK Ltd | Wimbledon | A rating |
| INTEGRATED RESEARCH UK LTD | Marlow | A rating |
| Integration Management Consulting Limited | London | A rating |
| Integreon Managed Solutions Ltd | London | A rating |
| Integrity NDT Limited | Chester | A rating |
| Intel Corporation (UK) Ltd | Salford | A rating |
| Intelex Europe Limited | Reading | A rating |
| Intellect Design Arena Limited | London | A rating |
| INTELLEX CONSULTING SERVICES LIMITED | Northwood | A rating |
| Intellian Limited | Uxbridge | A rating |
| Intellum UK Limited | West Sussex | A rating |
| Intelsat Global Sales & Marketing Limited | London | A rating |
| Intense Technologies UK Limited | Reading | A rating |
| Intentsify Limited | London | A rating |
| Interactive Brokers (U.K.) Limited | London | A rating |
| Interconnector Limited | London | A rating |
| InterContinental Hotels Group PLC | Windsor | A rating |
| Intercorp International Ltd | London | A rating |
| InterDigital Europe Ltd | London | A rating |
| InterGlobe Enterprises (UK) Limited | ADDLESTONE | A rating |
| Intergraph (UK) Limited | Swindon | A rating |
| Intermedia Technologies Company Ltd | Bristol | A rating |
| International Aids Vaccine Initiative, Inc. (IAVI) | Whitchurch | A rating |
| International Alert | London | A rating |
| International Automotive Components Group Limited | Birmingham | A rating |
| International Baccalaureate Organization (UK) Limited | Cardiff | A rating |
| International Committee of the Red Cross | London | A rating |
| International Construction Design & Management Ltd | Worcester | A rating |
| International Copyright Enterprise Services Limited | London | A rating |
| International Creative Management Ltd | London | A rating |
| International Flavours & Fragrances, I.F.F. (G.B.) Ltd | Haverhill | A rating |
| International General Insurance Company (UK) Limited | London | A rating |
| International Justice Mission UK | London | A rating |
| International Logistics Group Limited | Burgess Hill | A rating |
| INTERNATIONAL MANAGEMENT GROUP (UK) LIMITED | London | A rating |
| International Paint Limited | Gateshead | A rating |
| International Personal Finance Plc | Leeds | A rating |
| International Planned Parenthood Federation | London | A rating |
| International Power and Marine Group Limited | Burton on Trent | A rating |
| INTERNATIONAL POWER Ltd. | London | A rating |
| International Procurement & Logistics Limited | Wakefield | A rating |
| International Road Assessment Programme | Bracknell | A rating |
| International Society for Krishna Consciousness (ISKCON) | Aldenham, Watford | A rating |
| International SOS Assistance Limited | London | A rating |
| International Swaps and Derivatives Association, Inc | LONDON | A rating |
| International Transport Workers' Federation (ITF) | London | A rating |
| International Tubular Services Limited | Aberdeen | A rating |
| Internet Securities Limited | London | A rating |
| Internorm Windows UK Limited | London | A rating |
| Interogo Global Private Equity Advisors Ltd | London | A rating |
| Interpublic GIS UK Ltd | London | A rating |
| Interpublic Group | London | A rating |
| Interpublic Limited | London | A rating |
| Interquest Group (UK) Limited | Berkhamsted | A rating |
| Interspan Europe Limited | Shepperton | A rating |
| Interstate United Kingdom Management Ltd | Glasgow | A rating |
| Intersystems | Windsor | A rating |
| Intertek Group plc | London | A rating |
| Intesa Sanpaolo SpA London Branch | London | A rating |
| Intex Solutions Europe Limited | London | A rating |
| Intimate Apparel Retail UK Limited | Leicester | A rating |
| INTO MOVIT LTD | Bradford | A rating |
| IntraBio Ltd | London | A rating |
| Intradiem UK Limited | Bristol | A rating |
| Intrado Solutions Limited | Gloucester | A rating |
| Intralinks Ltd | London | A rating |
| Intratone UK Ltd | London | A rating |
| Intrepid Growth Partners (UK) LLP | LONDON | A rating |
| Intriva Services Limited | London | A rating |
| Introba Consulting Limited | London | A rating |
| Intuit Limited | London | A rating |
| Invasystems UK Ltd | Warrington | A rating |
| Invenics Services Ltd | London | A rating |
| Invenio Business Solutions Ltd | Wokingham | A rating |
| Invertek Drives Limited | Welshpool | A rating |
| Inverto UK Ltd | London | A rating |
| Invesco UK Limited | London | A rating |
| Invesis UK Limited | London | A rating |
| Investcloud Limited | London | A rating |
| Investcorp International Ltd | London | A rating |
| Investec Bank PLC | London | A rating |
| Investigo Limited | London | A rating |
| Investindustrial Corporate Services Limited | London | A rating |
| Investindustrial Management Limited | London | A rating |
| Investis Digital Limited | London | A rating |
| Investment Trends Limited | Norfolk | A rating |
| InvestorFlow UK Limited | London | A rating |
| Investra Capital Limited | London | A rating |
| Invexans Limited | London | A rating |
| Invinity Energy (UK) Limited | London | A rating |
| INVISTA Textiles (UK) Limited | London | A rating |
| Invus UK Limited | London | A rating |
| IODM (UK) Limited | London | A rating |
| IOI Brighton Limited | Brighton | A rating |
| IOI SERVICES LIMITED | London | A rating |
| ioMosaic International Limited | Bath | A rating |
| ION BEAM APPLICATIONS SA | NEWPORT | A rating |
| ION Trading UK Limited | London | A rating |
| Ionic Technologies International Limited | Belfast | A rating |
| IOPEX TECHNOLOGIES LTD | LONDON | A rating |
| IOTA Managed Services Ltd | Ascot | A rating |
| iota Sciences Limited | Oxford | A rating |
| IP Equipment Sales Ltd d/b/a Vermeer UK | Wellingborough | A rating |
| IP Fabric UK Limited | London | A rating |
| IP Global Properties Limited | London | A rating |
| IPC Information Systems | London | A rating |
| Ipca Laboratories UK Limited | Sunderland | A rating |
| IPG Health Medical Communications Ltd | London | A rating |
| iPipeline Limited | Cheltenham | A rating |
| IPMT Limited | London | A rating |
| Ippudo London Co Ltd | London | A rating |
| Ipsen Biopharm Limited | Wrexham | A rating |
| Ipsos Mori UK Limited | London | A rating |
| IQ EQ Administration Services (UK) Ltd | London | A rating |
| IQA OPERATIONS GROUP LIMITED | Edinburgh | A rating |
| IQE (Europe) Limited | St Mellons | A rating |
| IQPC Limited | London | A rating |
| IQT International UK Limited | London | A rating |
| IQVIA Laboratories Ltd | Livingston | A rating |
| IQVIA Limited | Reading | A rating |
| Iran Air, The Airline of the Islamic Republic of Iran | LONDON | A rating |
| Iranian Oil Company (UK) Ltd | Aberdeen | A rating |
| IRCA Manufacturing UK Limited | York | A rating |
| Irem General Contractor UK Limited | Southampton | A rating |
| iRemit Global Remittance Ltd. | London | A rating |
| Iress FS Limited | Cheltenham | A rating |
| IRG ADVISORS LLP | LONDON | A rating |
| iRhythm Technologies Limited | Bagshot | A rating |
| Iris Nation Worldwide Limited | London | A rating |
| IRISNDT Limited | Immingham | A rating |
| iRobot UK Limited | London | A rating |
| Ironclad Contracting UK Limited | London | A rating |
| IRONMAN Ltd. | Abingdon | A rating |
| ISA UK ENVELOPE SOLUTIONS Ltd | London | A rating |
| Isdel Energy Limited | Bristol | A rating |
| Ishida Europe Ltd. | Birmingham | A rating |
| ISKO SERVICES LIMITED | LONDON | A rating |
| Islestarr Holdings Limited | London | A rating |
| ISN Software UK Ltd | London | A rating |
| Isomorphic Labs Limited | London | A rating |
| ISS UK LIMITED | Weybridge | A rating |
| Istari Global Limited | London | A rating |
| Istituto Marangoni Ltd | London | A rating |
| ISUN- IMMIGRATION SUPPORT NETWORK LTD | LONDON | A rating |
| ISUZU TRUCK (UK) LIMITED | HATFIELD | A rating |
| IT Global (UK) Limited | London | A rating |
| IT Governance Ltd | Ely | A rating |
| itarle (UK) Limited | London | A rating |
| Itau BBA International plc | London | A rating |