Bedrift O - Ekeberg
- Olle AS
- Opticmain AS
- Osorno AS
- Olasv AS
- Oppmålingsvesenet AS
- Ogj Invest AS
- Oyshei Holding AS
- Oslo Bluesklubb
- Obayda Moussa
- Oscarsgate 2
- Olve Flakne
- Oscarsgate 2
- Orto Eiendom AS
- Overn Borettslag
- Overn Borettslag
- Ottemeier Education
- Olding Holding AS
- OBOS Eiendomsforvaltning AS
- OBOS Eiendomsdrift
- Oras Armatur AS
- OBOS Eiendomsforvaltning AS
- Ola Thingstad
- Oslo Lunsj
- Orienten Mat AS
- Oppegårdgata Veilag
- Oslo skinnspesialisten
- Oslo Lunsj AS
- Op Consult AS
- Osebna Izkaznica
- Orestes Turetskyy
- Olena Plakhova
- Oslo Klima AS
- Oslo Kyudo Forening
- OBOS Eiendomsmeglere Kværnerbyen
- Ose-Velles Idéeksplosjoner
- Oslo Lager Invest AS
- Outhwaite & Hasseltvedt DA
- Oso Hotwater Oslo
- Ole Dammen Holding AS
- Oliver Sale Dance
- Opp og Lovlig
- Opp og Lovlig
- Odd-Cato Kristiansen
- Oslo Kyudo Kyokai
- Ordmor Lisbeth Nilsen
- Op Knutsen Rådgivning AS
- Ole Morten Furuseth
- Olaf Olstad X2o
- Ole Rottereng Konsulent
- Olena Fomina Konkursbo
- Olena Fomina Konkursbo
- Oslo Sporveiers Skytterlag
- Oicun - Overrein Icu Nursing
- Ordskred By Anja Tolsrød
- Oliver Furuli Sport Consult
- Oda & Amund Holding AS
- Oslo Tentpegging Club Norway
- Ofstad Drager Interior And Design
- Oslo Audio & Video Service AS
- Oslo Fylkeslag, Norsk Tourette Forening
- Oslo Sporveiers Arbeiderforening Velferd T-Banen Verksted
- Oslo Sporveiers Arbeiderforening Velferd T-Banen Verksted