| Prosol AS | Professional & scientific | 2024 |
| Prototypelabs Network AS | Information & communication | 2017 |
| Pure & More AS | Wholesale & retail | 2025 |
| Pwrx AS | Other services | 2024 |
| Radoslav Bartak | Construction | 2004 |
| Reikvam Holding AS | Professional & scientific | 2013 |
| Resora AS | Wholesale & retail | 2025 |
| Reuters Consulting AS | Professional & scientific | 2020 |
| RGP Bolig AS | Real estate | 2008 |
| Roman Empire AS | | 2019 |
| Romerikeshow AS | Arts & recreation | 2014 |
| Roy Olsen AS | Professional & scientific | 1997 |
| Royal Invest AS | Transport & logistics | 2007 |
| Runestone Intelligence Limited Nuf | Information & communication | 2026 |
| Rustic Fool AS | Arts & recreation | 2017 |
| Ruud Utgraving Og Snødrift AS | Construction | 2026 |
| Rypeveien 15 AS | Real estate | 2021 |
| Rørteknik AS | Construction | 2018 |
| S-L Holding AS | Real estate | 2019 |
| Sace Consult AS | Arts & recreation | 2019 |
| Sanden Holding AS | | 1999 |
| Sanneland Invest AS | | 2026 |
| Saras Holding AS | Wholesale & retail | 2021 |
| Savir AS | Professional & scientific | 2014 |
| Scavenius Holding AS | | 2026 |
| Sennerud Eiendom AS | Real estate | 1994 |
| Sennerud Fus Barnehage AS | Education | 2018 |
| Sennerudtoppen Bolig 2 AS | Real estate | 2018 |
| Sennerudtoppen Bolig AS | Real estate | 2016 |
| Sennerudtoppen Næring 2 AS | Real estate | 2021 |
| Sennerudtoppen Næring 3 AS | Real estate | 2021 |
| Sennerudtoppen Næring 4 AS | Real estate | 2021 |
| Sennerudtoppen Næring 5 AS | Real estate | 2021 |
| Sennerudtoppen Parkering AS | Transport & logistics | 2017 |
| Senter for Utlendingsrett- Rettshjelper AS | Professional & scientific | 2020 |
| Shubidua Invest AS | Construction | 2017 |
| Si Massasje Og Fysioterapi AS | Health & social care | 2025 |
| Sibas Boligutvikling AS | Construction | 2012 |
| Sibas Eiendom AS | Real estate | 1985 |
| Silis AS | | 2024 |
| Skarpsynt Holding AS | | 2022 |
| Skogkanten Barnehage SA | Education | 2000 |
| Skolevegen 2 AS | Real estate | 2018 |
| Smartlook Optikk AS | Wholesale & retail | 2011 |
| Snare Eiendomsservice AS | Administrative & support | 2021 |
| Snitt & Stil AS | Other services | 2025 |
| Solvoll Boligutvikling AS | Real estate | 2014 |
| Sommern Ki Da | Information & communication | 2025 |
| Sooos AS | Transport & logistics | 2022 |
| Spenst Sørumsand AS | Arts & recreation | 2006 |
| Spice Village Da | Hospitality | 2025 |
| SPM Instrument AS | Wholesale & retail | 1980 |
| Stakkerud AS | | 2021 |
| STB 1-201 AS | Real estate | 2019 |
| Stovner Supermarked AS | Wholesale & retail | 2024 |
| STP 2 AS | Transport & logistics | 2024 |
| Streamhub AS | Information & communication | 2021 |
| Studio Alma AS | Professional & scientific | 2014 |
| Sudrheim Drift AS | Real estate | 2000 |
| Sudrheim Invest AS | Real estate | 2000 |
| Sudrheimgruppen Bolig AS | Real estate | 2009 |
| Sudrheimgruppen Eiendom AS | Real estate | 2009 |
| Sudrheimgruppen Entreprenør AS | Hospitality | 2007 |
| Sudrheimgruppen Lodges AS | Real estate | 2009 |
| Supreeya Massasje AS | Other services | 2019 |
| Svensgaard Mat AS | Wholesale & retail | 2023 |
| Sørlandet Resort Invest AS | Real estate | 2007 |
| Sørum Bil & Lakk AS | Other services | 2016 |
| Sørum Bilservice AS | Other services | 2006 |
| Sørum Håndverkertjenester AS | Construction | 2022 |
| Sørum Montør AS | Construction | 2020 |
| Sørum Multiteknikk Ans | Wholesale & retail | 2010 |
| Sørum Rennovasjon Og Tjenester AS | Construction | 2025 |
| Sørumsand Aktiv Fysio- Og Manuellterapi Da | Health & social care | 2018 |
| Sørumsand Eiendomsutvikling AS | Real estate | 2019 |
| Sørumsand Festivitetslokale SA | Real estate | 1935 |
| Sørumsand Isenkram & Farvehandel AS | Wholesale & retail | 1996 |
| Sørumsand Kvikk Rens Elsa Og Frank Jakobsen | Other services | 1980 |
| Sørumsand Legesenter AS | Health & social care | 1987 |
| Sørumsand Park AS | Real estate | 2026 |
| Sørumsand Pizza AS | Hospitality | 2023 |
| Sørumsand Rør AS | Construction | 1976 |
| Sørumsand Skotøyforretning AS | Real estate | 1980 |
| Sørumsand Sushi Og Wok AS | Hospitality | 2018 |
| Sørumsand Trafikkskole Ans | Education | 2000 |
| Sørumsand Trævare Fabrik AS | Real estate | 2008 |
| Sørumsand Zoosenter AS | Wholesale & retail | 2024 |
| Takst & Interiørpartner AS | Real estate | 2023 |
| Tanngarden AS | Health & social care | 1994 |
| Tanngarden Holding AS | Real estate | 2005 |
| Tannpleieren AS | Health & social care | 2024 |
| Teleheim AS | Hospitality | 2021 |
| Teokula AS | Real estate | 2025 |
| Termobud AS | Transport & logistics | 2018 |
| Tertitt Da | Wholesale & retail | 1990 |
| Tha Investments AS | | 2025 |
| The Eriksen Invest AS | Information & communication | 2022 |
| Tidvis AS | Information & communication | 2019 |
| Tidvis Formidling AS | Manufacturing | 2020 |
| Tigne AS | Professional & scientific | 2012 |