| OACU |  | | CY | Linde - Hadjikyriakos Gas Ltd. | www.linde-gas.com/ | |
| OAKU | | | US | Oak Ridge National Laboratory | www.ornl.gov/ | |
| OAKU | | | JP | Osaka Asahi Kaiun Co.,Ltd. | www.o-asahi.co.jp/ | |
| OASU | | | AE | Ocean Axis Shipping Services LLC. | www.oceanaxis.com/ | |
| OBHU | | | MY | Obetech Pacific Sdn. Bhd. | obetechpacific.com/ | |
| OBLU | | oceanblu | SG | OceanBlu Shipping (S) Pte. Ltd. | www.oblu.com.sg/ | |
| OBTU | | | CN | Jiangsu O-Best New Materials Co., Ltd. | www.o-bestjs.com/ | |
| OCAU |  | | CY | Ocean Box Containers Ltd. | oceanboxcontainers.com/ | |
| OCBU | | sitc | CN | Ocean Blue Finance Group Ltd. | www.oceanbluefg.com/ | |
| OCCU | | | NL | Orange Container Line BV. | www.orangecontainerline.com/ | |
| OCGU | | ocg | US | Textainer Equipment Management Ltd. | www.textainer.com/ | |
| OCTU | | ocean | ES | Ocean Containers Trading S.L. | contenedoresmaritimos.eu/ | |
| OCTU |  | samskip | NL | Samskip Multimodal Container Logistics BV. | www.samskip.com/ | |
| OCVU | | occ | NL | Overbeek Container Control | overbeekbv.nl/ | |
| OERU | | cosco | US | Precise Asset Sourcing LLC. | | |
| OEXU | | | ES | Marguisa Shipping Lines S.L.U. | www.marguisa.com/ | |
| OFLU | | chiwan oriental | HK | Shenzhen ChiWan Oriental Logistics Co., Ltd. | www.szcwol.com/ | |
| OFSU | | ohs | GB | Oilfield Hire & Services Ltd. | www.ohsuk.com/ | |
| OFTU | | | HK | Ocean First Logistics Ltd. | www.oceanfirst.com.hk/ | |
| OHKU | | | US | Tokyo Ohka Kogyo America Inc. | www.tokamerica.com/ | |
| OKCU | | cahata | SG | Cahaya Samudera Shipping Pte. Ltd. | www.cahayasamudera.com/ | |
| OKFU | | kurios | CA | Cirque du Soleil Inc. | www.cirquedusoleil.com/kurios | |
| OKKU | | | JP | Okinawa Kasei Kogyo Co., Ltd. | | |
| OKWU | | ndunese | MY | Ndunese Sealand Sdn. Bhd. | ndunese.com/ | |
| OLSU | | one stop | PH | One Stop Logistics Solutions | www.msl.com.ph/ | |
| OLTU | | | US | Odyssey Foodtrans LLC. | www.odysseylogistics.com/ | |
| OMAU | | oman | IE | Oman Secure Storage ( Oman Transport Ltd. ) | oman.ie/ | |
| OMCU | | omega chemicals | AU | Omega Chemicals Pty. Ltd. | omegachem.com.au/ | |
| OMLU | | | AE | Axis Fert Trade Dmcc. | www.orbitcargomanagement.com/ | |
| OMNU | | | IT | Air Liquid Italia Service S.r.l. | | |
| OMSU | | | PT | Orica Mining Services Portugal | www.orica.com/ | |
| ONEU | | one | SG | Ocean Network Express Pte. Ltd. | www.one-line.com/ | |
| ONLU | | asyad | OM | Oman Shipping Company S.O.A.C. | www.omanship.co.om/ | |
| ONTU | | onto | HK | New Onto Shipping International Ltd | | |
| OOCU | | oocl | HK | Orient Overseas Container Line Ltd. | www.oocl.com/ | |
| OOLU | | oocl | HK | Orient Overseas Container Line Ltd. | www.oocl.com/ | |
| OOOU | | | FR | Unauthorised prefix (on B.I.C. authority) | www.bic-code.org/ | |
| OPOU | | | MA | Commonwealth of Australia | | |
| OPTU | | optimodal | US | Odyssey Foodtrans LLC. | www.odysseylogistics.com/ | |
| ORAU | | | HK | Intermodal Logistics Ltd. | | |
| ORBU | | orbit | KE | Orbit Chemical Industries | www.orbitchem.com/ | |
| ORCU | | tml | ZA | Orca Container Asset Management | www.orca-sa.com/ | |
| ORGU | | | TR | Oregon Teknoloji Hizmetleri A.S. | oregon.com.tr/ | |
| ORPU | | | RU | Ocetrovskiy River Port ojc. | | |
| OSEU | | stolt | ZA | Ovenstone Holdings (Pty) Ltd. | | |
| OSHU | | omega | CZ | Omega Servis Holding a.s. | www.omegaservis.com/ | |
| OSKU | | oceanic | HK | Oceanic Star Line HK Ltd. | star-liners.com/ | |
| OSLU | | | DE | Ostermann Transporte GmbH. | ostermanntransporte.com/ | |
| OSMU | | | NZ | Koppers Performance Chemicals New Zealand | www.kopperspc.co.nz/ | |
| OSMU | | oss | AU | OSS Worldwide Movers | www.ossworldwidemovers.com/ | |
| OSPU | | | PE | Oxigeno Santa Clara S.A.C. | santaclarasac.com/ | |
| OSSU | | oss | AU | OSS Worldwide Movers | www.ossworldwidemovers.com/ | |
| OTGU | | ocean transport | PH | Ocean Transport Group of Companies Inc. | oceantransportgroup.com/ | |
| OTLU | | otl | MY | Overland Total Logistic Services (M) Sdn. Bhd. | www.otlsb.com/ | |
| OTPU | | | US | SeaCube Container Leasing Ltd. | seacubecontainers.com/ | |
| OTTU | | ottevanger | NL | Ottevanger Milling Engineers | www.ottevanger.com/ | |
| OWMU | | | AE | M/S. Magnum Technology Center | www.oilwellme.com/ | |
| OWNU | | | IT | Tarros Spa. Compagnia di Navigazione | www.tarros.it/ | |
| OXGU | | oxigas | ES | Oxigeno y Gases Licuados de Canarias S.L. | | |
| OXGU | | | SV | Infra de El Salvador S.A. de C.V. | www.infrasal.com/ | |
| OZTU | | özturk container | TR | Özturk Nakliyat ve Insaat San Tic Ltd. | www.ozturkcontainer.com/ | |
