| O. Borgen AS | Real estate | 2005 |
| Oddleiv Sæle Konsult AS | Professional & scientific | 2019 |
| Odin Granli Invest AS | | 2025 |
| Odnes Bygg Og Takst AS | Real estate | 2017 |
| Odontia 2 AS | Health & social care | 2016 |
| Oeal AS | | 2023 |
| Offcenit AS | Information & communication | 2017 |
| Oh-Holding AS | | 2024 |
| Oliven B.V AS | Hospitality | 2024 |
| Olivera Tannhelseteam AS | Health & social care | 2019 |
| Olsen Design Og Produksjon AS | Professional & scientific | 2022 |
| Olsens Øye AS | Health & social care | 2005 |
| Om Shanti AS | Arts & recreation | 2020 |
| Omsorgsbygg Innlandet AS | Real estate | 2020 |
| On Air AS | Administrative & support | 2000 |
| Onh Holding AS | | 2019 |
| Oppatt AS | Professional & scientific | 2023 |
| Oppland Oljefyringservice AS | Construction | 2020 |
| Opplandskraft Da | Energy | 1954 |
| Opplæringskontoret for Handel Håndverk Og Industri AS | Education | 2005 |
| Or Capital AS | | 2025 |
| Orby Consulting AS | Professional & scientific | 2011 |
| Ordskifte Forlag Da | Information & communication | 2019 |
| Orico Holding AS | Wholesale & retail | 1998 |
| Ornatu Da | Arts & recreation | 2025 |
| Os Iris AS | Information & communication | 2024 |
| Oslo Tool Company AS | Wholesale & retail | 2021 |
| Otto Fredriksson AS | Education | 2026 |
| Out of Bounds Lillehammer AS | Hospitality | 2022 |
| Overens Utvikling AS | Administrative & support | 2004 |
| Owren Defence Systems AS | | 2025 |
| P-Hus Kvartal 61 AS | Transport & logistics | 2015 |
| P4 Radio Hele Norge AS | Information & communication | 1992 |
| Paa Bordet AS | Hospitality | 2004 |
| Paaeventyr AS | Arts & recreation | 2022 |
| Pallan Søm Ans | Manufacturing | 1992 |
| Palmar AS | Information & communication | 2022 |
| Palunn Holding AS | | 2026 |
| Pamas Invest AS | Wholesale & retail | 2005 |
| Pantografen AS | Professional & scientific | 2018 |
| Pappa AS | Professional & scientific | 2018 |
| Parkcafeen AS | Hospitality | 1993 |
| Partnerpoint AS | Arts & recreation | 2025 |
| Pci AS | Professional & scientific | 2015 |
| Peelorg AS | Hospitality | 1991 |
| Peer Gynt Utvikling AS | Arts & recreation | 2018 |
| Pehki 750 Holding AS | | 2023 |
| Pein Holding AS | Other services | 2005 |
| Pele Invest AS | Real estate | 1975 |
| Pemto AS | | 2020 |
| Pengen Holding AS | | 2024 |
| Perfekt Brun Da | Other services | 2004 |
| Perfo Eiendom AS | Real estate | 2015 |
| Pero Takst AS | Real estate | 2016 |
| Peroni AS | Real estate | 2018 |
| Petrea AS | Hospitality | 2006 |
| Peve AS | Professional & scientific | 2007 |
| PHH AS | Professional & scientific | 2021 |
| Pkø AS | Professional & scientific | 1994 |
| Planet Hollywood Hårstudio Ans | Other services | 1993 |
| Poki-Heaven AS | Wholesale & retail | 2021 |
| Poku AS | Wholesale & retail | 2018 |
| Poku Netthandel AS | Wholesale & retail | 2026 |
| PPB Lillehammer AS | Wholesale & retail | 2023 |
| PR Utvikling AS | Real estate | 2021 |
| Praxis Arbeids Og Fritidsklær AS | Wholesale & retail | 1987 |
| Prevent Holding AS | Professional & scientific | 2006 |
| Prevent Systems AS | Professional & scientific | 2007 |
| Primetek Ans | Wholesale & retail | 1996 |
| Proff DG AS | Wholesale & retail | 2021 |
| Profilgutta AS | Professional & scientific | 2020 |
| Promedic AS | Education | 2020 |
| Propellen Holding AS | Financial services | 2005 |
| Prosit AS | Information & communication | 2016 |
| Prosjekt Og Eiendom AS | Real estate | 2022 |
| Prosjektco AS | Real estate | 2025 |
| Prosjektveilederen AS | Professional & scientific | 2018 |
| Pstens Holding AS | | 2022 |
| Psykolog Ingrid Meren AS | Health & social care | 2016 |
| Psykologspesialist Tollan AS | Health & social care | 2010 |
| PTS Invest AS | Real estate | 2012 |
| Pynten Eiendom AS | Real estate | 2003 |
| Pål Sommerseth AS | Wholesale & retail | 1994 |
| Pølsa AS | Arts & recreation | 2019 |
| Q2 Invest AS | Financial services | 2016 |
| Quan Holding AS | Hospitality | 2018 |
| Qvist Invest AS | | 2023 |
| R Transport AS | Transport & logistics | 2023 |
| R-Con AS | Professional & scientific | 2024 |
| Rabb Eiendom AS | Real estate | 2026 |
| Rafael Tech AS | Professional & scientific | 2024 |
| Rafal Fira AS | Health & social care | 2025 |
| Ragnvald Moe AS | Construction | 2020 |
| Rainy Day Productions AS | Information & communication | 2020 |
| Ram Arkitektur AS | Professional & scientific | 2004 |
| Ram Bygg AS | Real estate | 2018 |
| Randgaard Holding AS | Real estate | 2005 |
| Randgård Eiendom AS | Real estate | 1987 |
| Randgård Garasjelag SA | Transport & logistics | 2000 |
| Red-Corner AS | Wholesale & retail | 2017 |