| Invincto LP | | 2015 |
| Invisible Cities C.I.C. | Administrative & support | 2016 |
| Invisible Women Archives Ltd | Arts & recreation | 2022 |
| Invizius Limited | Manufacturing | 2018 |
| Invmarketworld Group LP | | 2017 |
| Inwealth LP | | 2015 |
| Inwest-Rem Ltd | Manufacturing | 2017 |
| Inyasha Ltd | Professional & scientific | 2025 |
| IO Partners LP | | 2020 |
| Iogp Limited Partnership | | 2017 |
| Iolto Partners | | 1999 |
| Iomet Pharma Ltd. | Professional & scientific | 2010 |
| ION Beam Services U.K. Limited | Administrative & support | 1997 |
| ION Wind Ltd | Construction | 2019 |
| Iona Business IP Limited | Professional & scientific | 2020 |
| Iona Corporation L.P. | | 2012 |
| Iona EI (SLP) II LP | | 2015 |
| Iona EI (SLP) III LP | | 2017 |
| Iona EI (SLP) LP | | 2011 |
| Iona NW (SLP) LP | | 2015 |
| Iona Russell Studio Ltd | Professional & scientific | 2024 |
| Iona Takeaway Ltd | Wholesale & retail | 2023 |
| Ionas Data & Software Ltd | Information & communication | 2025 |
| Ionate Limited | Professional & scientific | 2019 |
| Ionburst Limited | Information & communication | 2018 |
| Ionev Ltd | Information & communication | 2022 |
| Ionica Developments Limited | Professional & scientific | 2025 |
| Ionica Energy Consulting Limited | Professional & scientific | 2025 |
| Ionica Energy Limited | Professional & scientific | 2016 |
| Ionmhas Limited | Professional & scientific | 2019 |
| Ionocore Limited | Wholesale & retail | 2016 |
| IOQ Services Ltd | Professional & scientific | 2012 |
| Iotp (GP) Ltd | Real estate | 2017 |
| IP (Scot) LP | | 2018 |
| IP European Venture Fund (FP) LP | | 2008 |
| IP H&S Limited | Administrative & support | 2018 |
| IP HR Limited | Administrative & support | 2014 |
| IP Oncology Limited | Administrative & support | 2014 |
| IP Venture Fund (FP) Limited Partnership | | 2006 |
| IP Ventures (Scotland) Limited | Administrative & support | 2006 |
| IPA Energy + Water Economics Limited | Professional & scientific | 2005 |
| Ipen Trade LP | | 2012 |
| IPG AG LP | | 2015 |
| IPG PFP General Partner Limited | Financial services | 2011 |
| IPG PFP Limited Partner Limited | Financial services | 2011 |
| IPG PFP Scottish Limited Partnership | | 2011 |
| IPI Property Ltd | Real estate | 2021 |
| Ipona Limited | Information & communication | 1997 |
| Ipox Schuster Europe Limited | Information & communication | 2022 |
| IPP Technology LP | | 2013 |
| IPR Trading Limited | Hospitality | 2023 |
| Iprep Limited | Information & communication | 2018 |
| Iprr Limited | Hospitality | 2016 |
| IPS Adhesives Europe Ltd | Manufacturing | 1974 |
| IPS Alliance LP | | 2016 |
| IPS Product Supplies Limited | Wholesale & retail | 2002 |
| Ipserver LP | | 2016 |
| Ipso Facto Management Ltd | Administrative & support | 2009 |
| Ipsp LP | | 2017 |
| IQ Art Management L.P. | | 2017 |
| IQ Capital Founder Partnership Growth LP | | 2019 |
| IQ Capital Founder Partnership II LP | | 2013 |
| IQ Capital Founder Partnership III LP | | 2018 |
| IQ Capital Founder Partnership LP | | 2006 |
| IQ Couriers Ltd | Transport & logistics | 2025 |
| IQ Fire and Security Ltd | Construction | 2010 |
| IQ Founder Partner (GP) Growth Limited | Administrative & support | 2019 |
| IQ Founder Partner (GP) II Limited | Financial services | 2013 |
| IQ Founder Partner (GP) III Limited | Financial services | 2017 |
| IQ Founder Partner (GP) Limited | Administrative & support | 2006 |
| IQ Space Ltd | Real estate | 2024 |
| IQA Immigration Specialists Ltd | Professional & scientific | 2014 |
| IQA Operations Group Limited | Construction | 2002 |
| Iqanova Ltd | Professional & scientific | 2025 |
| IQB Investments Ltd | Real estate | 2017 |
| Iquality Systems Limited | Information & communication | 2012 |
| IR Technologies Limited | Information & communication | 2025 |
| Iras by Faiza Ltd | Wholesale & retail | 2026 |
| Irate Aves Ltd | Hospitality | 2023 |
| Iraz BEN Limited | Hospitality | 2025 |
| Irazols SP | | 2001 |
| Ireland Developments Ltd | Real estate | 2026 |
| Irene Napier Make-Up Design Ltd | Other services | 2012 |
| Irentify UK Limited | Wholesale & retail | 2023 |
| Irfan Taxi Ltd | Transport & logistics | 2018 |
| Iriada Trade LP | | 2017 |
| Iridium Scotland Limited Partnership | | 2010 |
| Iris 1 LP | | 2019 |
| Iris Global Holding LP | | 2017 |
| Irise World Ltd | Manufacturing | 2026 |
| Iriston House Dental Practice Limited | Health & social care | 2010 |
| Iron Code Ltd | Information & communication | 2016 |
| Iron Lantern Terrain Ltd | Manufacturing | 2026 |
| Iron Will Training Limited | Arts & recreation | 2014 |
| Iron Wing LP | | 2015 |
| Iron, Lithium, Xenon & Sulphur Ltd | Financial services | 2023 |
| Ironcore Games Ltd | Information & communication | 2025 |
| Irons Foulner Consulting Engineers Limited | Professional & scientific | 2013 |
| Ironside Systems Ltd | Information & communication | 2009 |
| Ironsky Barber Ltd | Other services | 2023 |