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| I&A Management AS | Oslo | 2019 |
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| Ib Renhold AS | Oslo | 2020 |
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| Id Holding AS | Holmestrand | 2011 |
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| Idemix Vending AS | Ranheim | 2024 |
| Idereiser AS | Kleppe | 2001 |
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| Idsø Holding AS | Jørpeland | 2012 |
| Idsø Vaktmesterservice AS | Jørpeland | 2008 |
| Idt-Innovar AS | Sola | 2023 |
| Idunn Shipping AS | Longyearbyen | 2025 |
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| If HR AS | Reistad | 2018 |
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| If Services Nuf | Oslo | 2017 |
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| Ifindtech Ltd | Essex Cm14 4Ba | 2022 |
| Ifix AS | Trondheim | 2013 |
| Ifjobb Eiendom AS | Leksvik | 2024 |
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| Igloo Base AS | Øverbygd | 2018 |
| Ignator AS | Søreidgrend | 2021 |
| Ihz AS | Notodden | 2023 |
| Iid AS | Kristiansand S | 2021 |
| Ijk Holding AS | Ballangen | 2021 |
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