| HSBC in Luxembourg | |
| IBISA | |
| ICBC (Europe) S.A. | |
| ICT Spring | Luxembourg |
| iDevlop | Capellen |
| IE Corp | |
| IEE S.A. | |
| Ilavska Vuillermoz Capital S.à r.l. | |
| Imagination Factory Lux S.à r.l. | |
| Inceptua S.A. | |
| Incert | |
| INDR | |
| Inetum Luxembourg S.A. | Luxembourg |
| infeurope S.A. | Luxembourg |
| InFinance | Luxembourg |
| Info Tech Solutions S.à r.l. | Luxembourg |
| Infodata Luxembourg | Capellen |
| Infrachain a.s.b.l. | Luxembourg |
| Inkspired | |
| InnoHub Luxembourg | Luxembourg |
| Innovat Homesystems S.A. | |
| Institut Luxembourgeois de Régulation | |
| Intec Software Engineering S.A. | Clervaux |
| InTech S.A. | Esch-sur-Alzette |
| Intelligentsia Consultants S.à.r.l. | |
| Interact | Luxembourg |
| Internetcalls | Luxembourg |
| INTRASOFT International S.A. | Luxembourg |
| Inverto.tv | Grevenmacher |
| Investify S.A. | |
| Invoke Luxembourg | Capellen |
| ION Group | Luxembourg |
| IQ-EQ | |
| IT One | Luxembourg |
| IT WORKS S.A. | Luxembourg |
| ITnation | Luxembourg |
| Itrust Consulting | |
| ITTM S.A. | |
| Jemmic S.à r.l. | |
| JobToday S.A. | |
| Joompay Europe S.A. | |
| Jway | Luxembourg |
| K-Skills Recrutement | |
| Key Job | Luxembourg |
| Keymitt S.A. | |
| Kidola | |
| Kinetik S.à.r.l. | |
| Kleos Space | Luxembourg |
| Kneip | |
| Knewledge | |