| O'Reilly Automotive Inc |
| O-I Glass, Inc. |
| Oberbank AG |
| Oberstdorfer Bergbahn AG |
| Obrascon Huarte Lain S.A. |
| OC Oerlikon Corporation AG Pfaeffikon |
| Ocado Group PLC |
| Occidental Petroleum Corp |
| Ocean Sun |
| OCI NV |
| Ocular Therapeutix Inc |
| Odfjell Drilling Ltd |
| Odfjell SE |
| Odfjell SE |
| Odfjell Technology Ltd |
| ODI Pharma |
| Odinwell |
| OeKOWORLD AG |
| OEM International AB |
| Oeneo SA |
| Oesterreichische Post AG |
| OGE Energy Corp |
| Ogunsen |
| OHB SE |
| Oil States International Inc |
| OKEA ASA |
| Okeanis Eco Tankers |
| Okta Inc |
| Olav Thon Eiendomsselskap ASA |
| Old Dominion Freight Line Inc |
| Old Republic International Corp |
| Olin Corp |
| Ollie's Bargain Outlet Holdings Inc |
| Olympus Corp |
| Oma Säästöpankki Oyj |
| Omega Healthcare Investors Inc |
| Omnicom Group Inc |
| OMV AG |
| ON Semiconductor Corp |
| Oncopeptides AB |
| OncoZenge |
| Oneflow AB |
| ONEOK Inc |
| Ontex Group NV |
| ONWARD Medical B.V. |
| Ooh!Media Limited |
| Open Lending Corp |
| Open Text Corp |
| Openlane Inc |
| Opera Software ASA |
| OPKO Health Inc |
| Opter AB |
| OptiCept Technologies AB |
| Optomed Oyj |
| Oracle Corp |
| Orange Belgium SA |
| Orange Polska SA |
| Orange SA |
| Orange SA |
| OraSure Technologies Inc |
| Orbis AG |
| Orchid Island Capital Inc |
| Orell Fuessli Holding AG |
| Öresund |
| Orexo AB |
| OrganoClick AB |
| Organon & Co |
| Orica Ltd. |
| Orient Overseas (International) Ltd. |
| Origin Energy Ltd. |
| Origin Enterprises PLC |
| Orion Oyj |
| Orior AG |
| Orkla ASA |
| Orlen S.A. |
| Orora Ltd. |
| Orrön Energy |
| Orthex Oyj |
| Ortivus AB |
| Ortivus AB |
| Ortoma AB |
| Ose Immunotherapeutics SA |
| OSRAM Licht AG |
| OssDsign |
| Otis Worldwide Corp |
| Otovo |
| OTP Bank Nyrt |
| Outokumpu Oyj |
| OVB Holding AG |
| Ovintiv Inc |
| Ovzon AB |
| Owens & Minor Inc |
| Owens Corning |
| OXE Marine |
| Oxford BioMedica PLC |
| Oxurion NV |
| OzForex Group Ltd. |
