| Kundenname | Stadt | Land | 
|---|---|---|
| OMV Downstream GmbH | Schwechat | Austria | 
| OMV Downstream GmbH | Wien | Austria | 
| OMV Petrom S.A. | Bucharest | Romania | 
| OMV Solutions GmbH | Wien | Austria | 
| ONGC Petro additions Ltd. | Mumbai | India | 
| OOO "Samson Controls" | Moskau | Russian Federation | 
| OOO Uhde Industrial Solutions (RUS) | Dzerzhinsk | Russian Federation | 
| Optitec Gesellschaft für ökonomische | Wiesbaden | Germany | 
| OQ Services GmbH | Oberhausen | Germany | 
| Ortner Ges.m.b.H. | Innsbruck | Austria | 
| OSCHATZ GmbH | Essen | Germany | 
| Österreichisches Forschungs- und Prüfzentrum | Wien | Austria | 
| OT Industries Asset Utilization LLC. | Budapest | Hungary | 
| OT Industries Eszközhasznosító Kft. | Budapest | Hungary | 
| Otto-von-Guericke-Universität Magdeburg | Magdeburg | Germany | 
| Outotec GmbH & Co KG | Oberursel | Germany | 
| Oveducon | Naaldwijk | Netherlands | 
| Oxxynova GmbH | Steyerberg | Germany | 
| OY Säätö Ab | Vantaa | Finland | 
| P & M Industrie-Anlagenplanung GmbH | Frechen | Germany | 
| P.A. Consultancies - KURZ Instruments Europe | Biddinghuizen | Netherlands | 
| PANAM ENGINEERS LTD. | Piludra, Ta. Prantij | India | 
| PANTOCHIM | Feluy | Belgium | 
| Par Pacific Holdings, Inc. | Houston | United States | 
| PARLYM Engineering | Marseille | France |