Bedrift O - Tonsenhagen
- Osike AS
- Onething Europe
- Onething Europe
- Olena Ivakhenko
- Oak Mtach AS
- O&M Holding AS
- Olsen Olsenssnekkerservice Morten
- O Hunnes Filmproduksjon
- Obsye Ibrahim Mohamed
- Oslo & Viken Renhold AS
- Oversetting og Litteraturformidling Maaike Lahaise
- Oslo & Viken Bygg AS Konkursbo
- Oslo & Viken Bygg AS Konkursbo
- Oslo Bygg Per Johan Ensio Wising