| Oslofjorden Eiendomsservice Da | Construction | 2003 |
| Oslogate 6 AS | Real estate | 2017 |
| Ostapchuk Holding & Consult AS | Health & social care | 2026 |
| Otg Solutions AS | Information & communication | 2020 |
| Overblikk Regnskap AS | Professional & scientific | 2019 |
| Oø Holding AS | | 2022 |
| P & a Invest AS | Financial services | 2015 |
| Padel Senter Fredrikstad AS | Education | 2023 |
| Paleomedicina Scandinavia AS | Health & social care | 2019 |
| Palle Omarsson Bygg Og Tømrerservice AS | Construction | 2013 |
| Palmiros Mat AS | Hospitality | 2026 |
| Paragutt AS | | 2025 |
| Paresa Holding AS | Hospitality | 2013 |
| Paresa Solli AS | Hospitality | 2016 |
| Paris Auto AS | Wholesale & retail | 2019 |
| Park Pluss AS | Administrative & support | 2017 |
| Partner Eiendom Da | Real estate | 1999 |
| Partner Solutions AS | Wholesale & retail | 2026 |
| Partnermed AS | Wholesale & retail | 1998 |
| Pas Devant Holdings AS | | 2023 |
| PBS Holding AS | Financial services | 2016 |
| Pcommerce AS | Professional & scientific | 2026 |
| Pear AS | Information & communication | 2017 |
| Pebro Invest AS | Professional & scientific | 2010 |
| Pegmatitt Holding AS | | 2018 |
| Pequod AS | | 2021 |
| Per&Per AS | Construction | 2024 |
| Performance Management AS | Professional & scientific | 2017 |
| Periskopet AS | Real estate | 2023 |
| Pers Trafikkskole AS | Education | 2007 |
| Perseverante AS | Administrative & support | 2010 |
| Persistante Da | Wholesale & retail | 2005 |
| Personlig Beredskap AS | Wholesale & retail | 2023 |
| Personlig Trening AS | Education | 2008 |
| Pesh Media AS | Information & communication | 2012 |
| Pesino AS | | 2019 |
| PFT Holding AS | Real estate | 2015 |
| PG Helsetjenester AS | Health & social care | 2025 |
| Phan Group AS | Hospitality | 2012 |
| PHK Invest AS | Wholesale & retail | 2005 |
| Phmt AS | Health & social care | 2026 |
| Picasso Pizza & Burgers AS | Hospitality | 2024 |
| Pine Investments AS | Financial services | 2013 |
| Pipeworks AS | Professional & scientific | 2025 |
| Pixel Invest AS | | 2017 |
| Pizzahuset Restaurantdrift AS | Hospitality | 2015 |
| Pizzaxpressen Vest AS | Hospitality | 2016 |
| Pizzeria Norge AS | Hospitality | 2012 |
| PJS Holding AS | Financial services | 2010 |
| PK Kystfiske AS | Agriculture & fishing | 2019 |
| PLAN9 Capital AS | Health & social care | 2021 |
| Plankebyen Barbershop AS | Other services | 2021 |
| Plankebyen Bygg AS | Construction | 2024 |
| Plankebyen Holding AS | Real estate | 2011 |
| Plankebyen Invest AS | | 2025 |
| Plankebyen Næringspark AS | Manufacturing | 2001 |
| Plankebyen Senter AS | Real estate | 1986 |
| Plankejens AS | Manufacturing | 2016 |
| Planken AS | Professional & scientific | 2026 |
| Plantago AS | Wholesale & retail | 2024 |
| Plast AS | Manufacturing | 2020 |
| Playshop Da | Wholesale & retail | 2001 |
| Plus Arkitektur AS | Professional & scientific | 2006 |
| Pluss & Minus AS | Professional & scientific | 1996 |
| PM Forvaltning AS | | 2024 |
| Pog Digital AS | Professional & scientific | 2016 |
| Polarbear Media AS | Professional & scientific | 2011 |
| Poms Tjenester AS | Professional & scientific | 2022 |
| Pongsri Hot Stone Massage AS | Other services | 2024 |
| Poorkar Bilutleie AS | Administrative & support | 2026 |
| Powerplay Group AS | Wholesale & retail | 2023 |
| PPM Prosjekt Fredrikstad AS | Professional & scientific | 2022 |
| Pre Invest AS | | 2005 |
| Preferium AS | Information & communication | 2012 |
| Prek AS | Professional & scientific | 2022 |
| Prekas AS | Information & communication | 2026 |
| Premium Boligfoto AS | Professional & scientific | 2023 |
| Presedens Nettbutikk AS | Wholesale & retail | 2017 |
| Presis Bygg Og Anlegg AS | Construction | 2012 |
| Presisjonsverket AS | Other services | 2025 |
| Prestelandet Boligandelslag AS | Households | 1959 |
| Prima Tannklinikk AS | Health & social care | 2024 |
| Primalis AS | | 2012 |
| Prime Food AS | Hospitality | 2026 |
| Prime Partners Holding AS | Health & social care | 2024 |
| Prime Regnskap AS | Professional & scientific | 2026 |
| Privattannlegene Tore Karlsen AS | Health & social care | 2019 |
| Prive Fredrikstad AS | Other services | 2025 |
| Procon Invest AS | Professional & scientific | 2007 |
| Produksjonsveien 12 AS | Manufacturing | 2012 |
| Produksjonsveien 13 AS | Real estate | 2025 |
| Produksjonsveien 19 AS | Real estate | 2024 |
| Produksjonsveien 21 AS | Real estate | 2024 |
| Produksjonsveien 24 AS | Real estate | 2018 |
| Profag Norge AS | Wholesale & retail | 2014 |
| Proff Byggkonsulent AS | Professional & scientific | 2021 |
| Proff Electronic Da | Other services | 1993 |
| Proff Solcelle AS | Construction | 2023 |
| Proptech Invest AS | | 2021 |
| Prosjekteringsgruppen AS | Professional & scientific | 2026 |