| ITC Global (UK) Limited | Aberdeen | A rating |
| ITC Infotech Limited | London | A rating |
| Itential Europe Ltd | Holborn | A rating |
| Iterable Limited | London | A rating |
| Ithaca College | London | A rating |
| Itineris Software UK Ltd | Kingston upon Thames | A rating |
| ITM Power Plc | Sheffield | A rating |
| ITO EN EUROPE GMBH UK BRANCH | London | A rating |
| ITOCHU Europe PLC | London | A rating |
| ITP Aero UK Limited | Hucknall | A rating |
| ITP Engines UK Limited | Leicester | A rating |
| Itransition Group Limited | London | A rating |
| Itron Metering Solutions UK Ltd | Martlesham | A rating |
| iTrust Group Ltd | Luton | A rating |
| ITSEC LTD | Leicester | A rating |
| ITT Industries Limited | Basingstoke | A rating |
| ITV plc | London | A rating |
| ITvantage Systems Limited | Essex | A rating |
| ITW Construction Products - Division of ITW Limited | Glenrothes | A rating |
| ITW Envopak, division at ITW Limited | Sidcup | A rating |
| ITX UK Limited | London | A rating |
| IUCN World Conservation Union | Cambridge | A rating |
| IUP2 LLP | Brighton | A rating |
| Ivalua Ltd | London | A rating |
| Ivanhoe Cambridge Holdings UK Ltd t/a La Caisse | London | A rating |
| Ivanti UK Limited | Bracknell | A rating |
| IVECO LIMITED | Basildon | A rating |
| Ivoclar-Vivadent Limited | Leicester | A rating |
| IW Group Services (UK) Limited | London | A rating |
| IWBI (UK) Limited | London | A rating |
| Ixxus Limited | London | A rating |
| J & E Hall Limited | Dartford | A rating |
| J C Bamford Excavators Ltd | Staffordshire | A rating |
| J D Sports Fashion PLC | Bury | A rating |
| J O Hambro Capital Management Ltd | London | A rating |
| J. Choo Limited | London | A rating |
| J.D Power UK Limited | Swansea | A rating |
| J.LEAGUE EUROPE | Maidenhead | A rating |
| J.S. Held UK Limited | London | A rating |
| J&T EXPRESS UK LTD | Lutterworth | A rating |
| J2 Global UK Ltd. | London | A rating |
| Jabil Circuit Limited | Livingston | A rating |
| JAC Recruitment (UK) Limited | London | A rating |
| Jack Morton Worldwide | London | A rating |
| Jack's Creek UK Limited | London | A rating |
| Jacobi Carbons Limited | Leigh | A rating |
| Jacobi EMEA Limited | London | A rating |
| Jacobs Douwe Egberts GB Limited | Maidenhead | A rating |
| Jacobs Holding LLP | London | A rating |
| Jacobs UK Ltd | Wokingham | A rating |
| Jade Software Corporation UK Ltd | Harrogate | A rating |
| JAE Europe Limited | Aldershot | A rating |
| Jaguar Land Rover Limited | Coventry | A rating |
| Jaguar Resources and Capital UK Ltd | London | A rating |
| Jaivel Aerospace Limited | Mansfield | A rating |
| JAKKS PACIFIC (UK) LTD | Bracknell | A rating |
| Jalpak International (Europe) B.V. | London | A rating |
| Jalux Inc. Europe Branch | London | A rating |
| James Dewhurst Ltd | Accrington | A rating |
| James Finlay Limited | London | A rating |
| James Madison University & JMU Overseas Programs Ltd | London | A rating |
| Janan Limited | Bradford | A rating |
| Jane Street Europe Limited | London | A rating |
| Jane's Group UK Limited | Croydon | A rating |
| Janome UK Ltd | Stockport | A rating |
| Janssen-Cilag Ltd | High Wycombe | A rating |
| JANUS ET CIE U.K. LIMITED | London | A rating |
| JANUS HENDERSON ADMINISTRATION UK LIMITED | LONDON | A rating |
| Japan Airlines Co. Ltd | London | A rating |
| Japan Bank for International Cooperation | London | A rating |
| Japan England Insurance Brokers Ltd | London | A rating |
| Japan Exchange Group, Inc. | London | A rating |
| Japan Foundation, London | London | A rating |
| Japan National Tourism Organization | London | A rating |
| JAPN SOCIETY FOR THE PROMOTION OF SCIENCE | London | A rating |
| Jas Forwarding (UK) Limited | Feltham | A rating |
| JASCO Applied Sciences (UK) Ltd | Droxford | A rating |
| Jasper Ridge Services UK Limited | London | A rating |
| JATCO UK Ltd | Sunderland | A rating |
| JATO Dynamics Limited | Uxbridge | A rating |
| Java Investments Management PLC | London | A rating |
| Javlin Ltd | London | A rating |
| Jawaby Services and Investment Limited | London | A rating |
| Jay Jay UK Private Limited | Watford | A rating |
| Jazz Pharmaceuticals UK Limited | London | A rating |
| JB Drax Honore (UK) Ltd | London | A rating |
| JBCConnect Limited | London | A rating |
| JBS Global (UK) Limited | Uxbridge | A rating |
| JCB International (Europe) Ltd | London | A rating |
| JCK Ltd | Colnbrook | A rating |
| JCR Group Ltd | London | A rating |
| JD.COM International UK Ltd | Lutterworth | A rating |
| JDR Cable Systems Ltd | Littleport | A rating |
| Jefferies International Limited | London | A rating |
| JELD-WEN Europe Ltd | Solihull | A rating |
| Jellyfish Group Ltd | Reigate | A rating |
| Jellysmack Limited | London | A rating |
| JEMELLA LTD | LEEDS | A rating |
| Jenner & Block London LLP | London | A rating |
| JEOL (U.K.) LIMITED | WELWYN GARDEN CITY | A rating |
| JERA Global Markets Pte. Ltd. (London) | London | A rating |
| Jera Nex BP Limited | Sunbury on Thames | A rating |
| JERA NEX LIMITED | London | A rating |
| Jeremy Gardner Associates Ltd | London | A rating |
| Jerich UK Ltd | Skelmersdale | A rating |
| Jet2.com | Leeds | A rating |
| Jetcraft Global (UK) Limited | London | A rating |
| JETRO London (Japan External Trade Organization) | London | A rating |
| JFC (UK) Ltd | Hayes | A rating |
| JFI Healthcare Limited | London | A rating |
| JFrog UK Limited | London | A rating |
| JGC Corporation UK Limited | London | A rating |
| Jiangsu Provincial Economic and Trade Office in the UK | London | A rating |
| JIJ EUROPE LTD | Harwell Campus | A rating |
| Jingdong Property Asset Management UK Limited | London | A rating |
| Jingdong Retail UK Limited | London | A rating |
| JK Tech UK LTD | London | A rating |
| JLG Industries (United Kingdom) Limited | Manchester | A rating |
| JLG Legal Limited | Manchester | A rating |
| JMAN Group Limited | London | A rating |
| JMD Railtech Limited | York | A rating |
| JMI Salons Limited | London | A rating |
| JMJ Associates Ltd | London | A rating |
| JN Bank UK Ltd | London | A rating |
| JN Money Services (UK) Limited | London | A rating |
| JOBA INTERNATIONAL LONDON LTD | LONDON | A rating |
| Jobandtalent UK Limited | London | A rating |
| Joe and the Juice UK Ltd | London | A rating |
| JOGMEC(Japan Organization for Metals and Energy Security) | London | A rating |
| Joh. Berenberg, Gossler & Co. KG, London Branch | London | A rating |
| John Bean Technologies Limited | Livingston | A rating |
| John Brown University Northern Ireland | Belfast | A rating |
| John Crane UK Limited | Slough | A rating |
| John Deere Limited | Langar | A rating |
| John Paul Construction Limited | Bracknell | A rating |
| John Sisk & Son Ltd | St. Albans | A rating |
| John West Foods Limited | Liverpool | A rating |
| John Wiley & Sons Limited | Bognor Regis | A rating |
| Johnson & Johnson Medical Ltd | West Lothian | A rating |
| Johnson Matthey Plc | London | A rating |
| Join the Dots (Research) Ltd | Manchester | A rating |
| Jokey UK Limited. | Corby | A rating |
| Jollofe Ltd | Rainham | A rating |
| Jones Knowles Ritchie Ltd | London | A rating |
| Jones Lang LaSalle Limited | London | A rating |
| Jones Lang LaSalle Services LTD | London | A rating |
| JonesTrading International Limited | London | A rating |
| Jordan International Bank | London | A rating |
| Joseph gallagher ltd | orsett | A rating |
| Joseph Limited | London | A rating |
| JOSH & JAKE CHINNAIYAN LTD | Birmingham | A rating |
| Jotun Paints (Europe) Ltd | Flixborough | A rating |
| JOULE ENERGY UK LTD | LONDON | A rating |
| Joy Global (UK) Limited | Bolton | A rating |
| Joy Global (UK) Ltd | Bolton | A rating |
| Joyalukkas Limited | London | A rating |
| Joyce Wang London Limited | London | A rating |
| JP Renewable Europe Company Limited | London | A rating |
| JPMorgan Chase Bank, National Association | London | A rating |
| JPT EUROPE LTD. | London | A rating |
| JRE BUSINESS DEVELOPMENT UK LIMITED | London | A rating |
| JRI Europe Ltd | London | A rating |
| JS HEALTH VITAMINS UK LTD | London | A rating |
| JS International Trade UK ltd | Kingston Upon Thames | A rating |
| JSP Limited | Minster Lovell | A rating |
| JTB Europe Ltd | London | A rating |
| JTC (UK) Limited | London | A rating |
| JTEKT Automotive England Ltd | Barnsley | A rating |
| JTRE London Ltd | London | A rating |
| JTRI Limited | Preston | A rating |
| Judilica UK Ltd t/a Legora | London | A rating |
| Juicebox UK Ltd | Altrincham | A rating |
| Jukin Media Limited | London | A rating |
| Julius Baer International Limited | London | A rating |
| Juls London Limited | London | A rating |
| Jumar Solutions Limited | Birmingham | A rating |
| JUMO Europe Limited | London | A rating |
| Jump Trading International Limited | London | A rating |
| JUNEYAO AIRLINES CO., LTD (UK BRANCH) | Manchester | A rating |
| Jungheinrich UK Limited | Milton Keynes | A rating |
| Juni Financial Limited | London | A rating |
| JUNIOR AI LIMITED | London | A rating |
| Jupiter Asset Management Limited | London | A rating |
| Jupitor Corporation | Preston | A rating |
| Jusan Technologies Ltd | London | A rating |
| Just Eat Holding Limited | London | A rating |
| Just Global UK Ltd | Maidenhead | A rating |
| Justworks Employment UK Ltd. | London | A rating |
| Juvenesence UK Limited | London | A rating |
| JVCKENWOOD U.K. Limited | Watford | A rating |
| JW Player UK Ltd | London | A rating |
| K Line (Europe) Limited | London | A rating |
| K Line Bulk Shipping (UK) Limited | LONDON | A rating |
| K Line Logistics (UK) Ltd | Feltham | A rating |
| K. A. Javid & Co | Glasgow | A rating |
| K. MIKIMOTO & CO., LTD. | London | A rating |
| K&L Gates LLP | London | A rating |
| K2 Consultancy Limited | London | A rating |
| K2 Corporate Mobility Limited | Guildford | A rating |
| K2 Group Holdings Limited | London | A rating |