| Wiegaard Invest AS | Real estate | 2010 |
| Wiik Anlegg AS | Administrative & support | 2020 |
| Wiik Entreprenør AS | Construction | 2016 |
| Wileo AS | Information & communication | 2020 |
| Wilhelm Wetlesensvei 1 AS | Real estate | 2021 |
| Wilmann Invest AS | Financial services | 2011 |
| Wine Down AS | Hospitality | 2018 |
| Winterspring Holding AS | Construction | 2019 |
| Wio AS | Real estate | 2017 |
| Wisco-T Import & Trading Ans | | 1989 |
| Wolf Holding AS | | 2022 |
| Wolf Invest AS | Professional & scientific | 2020 |
| Wood Group Norway AS | Mining & quarrying | 1996 |
| Wood I Decor AS | Other services | 2017 |
| WS Transport AS | Wholesale & retail | 2012 |
| Wulfsberg Utvikling AS | Real estate | 2019 |
| WW Invest AS | Professional & scientific | 2012 |
| Wågnes AS | Health & social care | 1994 |
| Xacton AS | Information & communication | 2019 |
| Xbay Capital AS | Professional & scientific | 2021 |
| Xilin AS | Hospitality | 2026 |
| Xl-Tech Inneklima AS | Construction | 2024 |
| Xmarket Northern Opportunities AS | Wholesale & retail | 1999 |
| Xtraservice AS | Health & social care | 2020 |
| Yam Yam Restaurant AS | Hospitality | 2025 |
| Yamaduo AS | Information & communication | 2026 |
| Yellow Sandefjord AS | Wholesale & retail | 2024 |
| Yj Consulting AS | Professional & scientific | 2022 |
| York AS | Construction | 1999 |
| Ystenes Invest AS | | 2025 |
| Ytterbø Eiendom AS | Real estate | 2018 |
| Yxeney Services AS | Information & communication | 2022 |
| Zafena AS | Wholesale & retail | 2013 |
| Zaka AS | Transport & logistics | 2015 |
| Zal AS | Financial services | 2014 |
| Zengler Invest AS | | 2022 |
| Zenith AS | Professional & scientific | 2022 |
| Ziggy Trading AS | | 2025 |
| Zimba AS | | 2018 |
| Zimm Holding AS | Real estate | 1997 |
| Zirqus AS | Wholesale & retail | 2009 |
| Zoes Bygg AS | Construction | 2025 |
| Zoonature AS | Wholesale & retail | 2005 |
| ZR1 Holding AS | Wholesale & retail | 2016 |
| Zrian Frisør AS | Other services | 2022 |
| Zyminvest AS | Real estate | 2005 |
| ZZZ Norge AS | Administrative & support | 2023 |
| Åbol Shopping & Take Away Da | Wholesale & retail | 2007 |
| Åge Børresen Holding 2 AS | | 2025 |
| Åge Børresen Holding 3 AS | | 2025 |
| Åge Børresen Holding AS | Manufacturing | 2023 |
| Åge Børresen Stempelfabrikk AS | Manufacturing | 1987 |
| Åpen Bok AS | Arts & recreation | 2022 |
| Årstein Consulting AS | Professional & scientific | 2024 |
| Årstein Holding AS | | 2017 |
| Årø Vest Utbyggingsselskap SA | Construction | 2023 |
| Årø Vest Vann Og Avløp SA | Water & waste | 2024 |
| Årøtangen Og Sauholmen Vannlag SA | Water & waste | 2026 |
| Åsane Apotek AS | Wholesale & retail | 2020 |
| Åsen Drift AS | Administrative & support | 2022 |
| Åtte Eiendomsinvest AS | | 2024 |
| Æ Holding AS | | 2026 |
| Ærfugl AS | Real estate | 2022 |
| Ø. Seim AS | Real estate | 2013 |
| Øre AS | Real estate | 2015 |
| Ørjan Management Da | Professional & scientific | 2026 |
| Øst Invest AS | Financial services | 1998 |
| Østerøy Naturbarnehage SA | Education | 1990 |
| Østerøya AS | Real estate | 2019 |
| Østerøyveien 36 AS | Real estate | 2024 |
| Østhell AS | Professional & scientific | 2007 |
| Østkyst Eiendom AS | Real estate | 2022 |
| Østre Langeby Bryggelag Samvirkeforetak | Transport & logistics | 2005 |
| Østre Nes Va-Anlegg SA | Water & waste | 1990 |
| Øvre Gokstad Utvikling AS | Real estate | 2018 |
| Øvre Haslevei 11 AS | Real estate | 1998 |
| Øvrum Invest AS | Real estate | 2007 |
| Øya 45 Eiendom AS | Real estate | 2025 |
| Øyans Bil Eiendom AS | Real estate | 2006 |
| Øyans Bil Sandefjord AS | Wholesale & retail | 1994 |
| Øyelege Cathrine Hansli AS | Health & social care | 2018 |
| Øyen Holding AS | Professional & scientific | 2023 |
| Øyespesialistene AS | Health & social care | 2018 |
| Øyka AS | Real estate | 2023 |
| Øyla AS | Real estate | 2005 |
| Øyvind Horn Holding AS | Professional & scientific | 2018 |
| Øyvind Osdalen Bygg AS | Construction | 2022 |