- OBAM Investment Management BV
- ODDO BHF Asset Management GmbH
- ODDO BHF Asset Management Lux
- ODDO BHF Asset Management SAS
- Odey Asset Management LLP
- OFI Asset Management
- Ökoworld Lux S.A.
- One Fund Management SA
- Optigestion Europe
- OPTINOVA Investment AG
- Orbis Investment Management (Luxembourg) SA
- Osprey
- Ossiam
- OTP invest d.o.o.