| Companies listed on the NASDAQ |
| Equity | Symbol | Info |
|---|
| O Reilly Automotive Inc | ORLY |     |
| O. I. Corp. (MM) | OICO | |
| O2Micro International Limited ADS (MM) | OIIMD | |
| OCA Acquisition Corporation | OCAX | |
| ODP Corporation | ODP | |
| OFS Capital Corporation | OFS | |
| OFS Capital Corporation | OFSSL | |
| OFS Capital Corporation | OFSSG | |
| OFS Capital Corporation | OFSSI | |
| OFS Capital Corporation | OFSSZ | |
| OFS Credit Company Inc | OCCI | |
| OHA Investment Corporation | OHAI | |
| OLB Group Inc | OLB | |
| OMNIQ Corporation | OMQS | |
| ON Semiconductor | ON | |
| ONE Group Hospitality Inc | STKS | |
| OP Bancorp | OPBK | |
| ORBCOMM Inc | ORBC | |
| OSI Systems Inc | OSIS | |
| OTR Acquisition Corporation | OTRA | |
| Oak Hill Financial (MM) | OAKF | |
| Oak Ridge Financial Services (MM) | BKORD | |
| Oak Technology (MM) | OAKT | |
| Oak Valley Bancorp | OVLY | |
| Oaktree Specialty Lending Corporation | OCSL | |
| Oaktree Specialty Lending Corporation | OCSLL | |
| Oaktree Strategic Income Corporation | OCSI | |
| Oao Technology Solutions (MM) | OAOT | |
| Oasis Midstream Partners LP | OMP | |
| Oasis Petroleum Inc | OAS | |
| Obagi Medical Products, Inc. (MM) | OMPI | |
| Obalon Therapeutics Inc | OBLN | |
| Oblong Inc | OBLG | |
| ObsEva SA | OBSV | |
| Occam Networks (MM) | OCNW | |
| Occulogix (MM) | OCCXD | |
| Occulogix (MM) | RHEO | |
| Occulogix (MM) | OCCX | |
| Ocean Bio Chem Inc | OBCI | |
| Ocean Power Technologies Inc | OPTT | |
| Ocean Rig Udw Inc. New (delisted) | ORIG | |
| Ocean Rig Udw Inc. (MM) | ORIGV | |
| Ocean Shore Holding CO. (MM) | OSHCD | |
| Ocean Shore Holding Co. | OSHC | |
| OceanFirst Financial Corporation | OCFC | |
| OceanTech Acquisitions I Corporation | OTEC | |
| Oceanfreight Inc. (MM) | OCNF | |
| Oceanfreight Inc. (MM) | OCNFD | |
| Ocera Therapeutics, Inc. (MM) | OCRX | |
| Ocharleys Inc. (MM) | CHUX | |
| Oclaro (MM) | OCLRE | |
| Oclaro (MM) | OCLRD | |
| Oclaro, Inc. (delisted) | OCLR | |
| Oconee Federal Financial Corporation | OFED | |
| Ocugen Inc | OCGN | |
| Ocular Therapeutix Inc | OCUL | |
| Ocuphire Pharma Inc | OCUP | |
| Odd Job Stores (MM) | ODDJ | |
| Odetics CL A (MM) | ODETA | |
| Odonate Therapeutics Inc | ODT | |
| Odyssey Healthcare (MM) | ODSY | |
| Odyssey Marine Exploration Inc | OMEX | |
| Office Properties Income Trust | OPINL | |
| Office Properties Income Trust | OPINI | |
| Office Properties Income Trust | OPI | |
| Official Payments Holdings, Inc. (MM) | OPAY | |
| Oglebay Norton Company (MM) | OGLE | |
| Ohio Casualty (MM) | OCAS | |
| Ohio Legacy Corp. (MM) | OLCB | |
| Ohio Valley Banc Corporation | OVBC | |
| Ohr Pharmaceuticals, Inc. | OHRP | |
| Oilgear | OLGR | |
| Okta Inc | OKTA | |
| Old Dominion Freight Line Inc | ODFL | |
| Old Line Bancshares Inc | OLBK | |
| Old National Bancorp | ONB | |
| Old Point Financial Corporation | OPOF | |
| Old Second Bancorp Inc | OSBC | |
| Olema Pharmaceuticals Inc | OLMA | |
| Ollies Bargain Outlet Holdings Inc | OLLI | |
| Olympic Steel Inc | ZEUS | |
| Omega Alpha SPAC | OMEG | |
| Omega Financial (MM) | OMEF | |
| Omega Flex Inc | OFLX | |
| Omega Navigation Enterprises, Inc. (MM) | ONAV | |
| Omega Therapeutics Inc | OMGA | |
| Omeros Corporation | OMER | |
| Omni Energy Svcs Corp (MM) | OMNI | |
| Omnicell Inc | OMCL | |
| Omniture (MM) | OMTR | |
| Omrix Biopharmaceuticals (MM) | OMRI | |
| Omthera Pharmaceuticals, Inc. (MM) | OMTH | |
| On Track Innovations Ltd | OTIV | |
| OncoSec Medical Incorporated | ONCS | |
| Oncobiologics - Series B Warrant (delisted) | ONSIZ | |
| Oncobiologics Series A Warrant Expiring 2/18/2019 (delisted) | ONSIW | |
| Oncobiologics Unit (MM) | ONSIU | |
| Oncobiologics, Inc. (delisted) | ONS | |
| Oncocyte Corporation | OCX | |
| Oncolytics Biotech Inc | ONCY | |
| Oncomed Pharmaceuticals, Inc. | OMED | |
| Onconova Therapeutics Inc | ONTX | |
| Oncorus Inc | ONCR | |
| Oncternal Therapeutics Inc | ONCT | |
| Ondas Holdings Inc | ONDS | |
| One Bio Corp Cmn (MM) | ONBIE | |
| One Equity Partners Open Water I Corporation | OEPW | |
| One Stop Systems Inc | OSS | |
| OneSpaWorld Holdings Ltd | OSW | |
| OneSpan Inc | OSPN | |
| OneWater Marine Inc | ONEW | |
| Oneida Financial (MM) | ONFCD | |
| Onesource Information Services (MM) | ONES | |
| Online Resources Corp. (MM) | ORCC | |
| Onstream Media (MM) | ONSMD | |
| Onstream Media Corp. (MM) | ONSM | |
| Ontrak Inc | OTRK | |
| Onvia, Inc. (MM) | ONVI | |
| Onyx Pharmaceuticals, Inc. (MM) | ONXX | |
| Onyx Software (MM) | ONXS | |
| OpGen Inc | OPGN | |
| Open Lending Corporation | LPRO | |
| Open Text Corporation | OTEX | |
| Opendoor Technologies Inc | OPEN | |
| Opentv (MM) | OPTV | |
| Opes Acquisition Corporation | OPES | |
| Opes Acquisition Corporation | OPESU | |
| Ophthotech Corp. | OPHT | |
| Opiant Pharmaceuticals Inc | OPNT | |
| Opinion Research | ORCI | |
| Opko Health Inc | OPK | |
| Oplink Communications (MM) | OPLKD | |
| Opnext, Inc. (MM) | OPXT | |
| Oportun Financial Corporation | OPRT | |
| Opsware (MM) | OPSW | |
| Optelecom-Nkf, Inc. (MM) | OPTC | |
| OptiNose Inc | OPTN | |
| Optibase Ltd | OBAS | |
| Optical Cable Corp. (MM) | OCCF | |
| Optical Cable Corporation | OCC | |
| Optical Communic Proda (MM) | OCPI | |
| Optika Inc. (MM) | OPTK | |
| Optimal Grp. (MM) | OPMRD | |
| Optimal Grp. CL a (MM) | OPMR | |
| Optimer Pharmaceuticals, Inc. (MM) | OPTR | |
| OptimizeRx Corporation | OPRX | |
| OptimumBank Holdings Inc | OPHC | |
| Optimumbank Holdings (MM) | OPHCD | |
| Option Care Health Inc | OPCH | |
| Option Care Health Inc | BIOS | |
| Optionsxpress Holdings, Inc. (MM) | OXPS | |
| Optium Corp (MM) | OPTM | |
| Opus Bank | OPB | |
| OraSure Technologies Inc | OSUR | |
| Oralabs | OLAB | |
| Oramed Pharmaceuticals Inc | ORMP | |
| Orange County Bancorp Inc | OBT | |
| Orbital Energy Group Inc | OEG | |
| Orbitz CL A (MM) | ORBZ | |
| Orbotech Ltd. - Ordinary Shares | ORBK | |
| Orbsat Corporation | OSAT | |
| Orchard Enterprise (MM) | ORCD | |
| Orchard Therapeutics PLC | ORTX | |
| Orchid Cellmark (MM) | ORCH | |
| Ore Pharmaceuticals (MM) | ORXED | |
| Oregon Trail Financial (MM) | OTFC | |
| Organigram Holdings Inc | OGI | |
| Organogenesis Holdings Inc | ORGO | |
| Organovo Holdings Inc | ONVO | |
| Orgenesis Inc | ORGS | |
| Oric Pharmaceuticals Inc | ORIC | |
| Oriental Culture Holdings Ltd | OCG | |
| Origin Agritech Ltd | SEED | |
| Origin Agritech Ltd Wrts (MM) | SEEDW | |
| Origin Bancorp Inc | OBNK | |
| Origin Materials Inc | ORGN | |
| Origo Acquisition Corp. - Ordinary Shares (delisted) | OACQ | |
| Origo Acquisition Corp. - Right Expiring 3/12/2018 (delisted) | OACQR | |
| Origo Acquisition Corp. - Unit (delisted) | OACQU | |
| Origo Acquisition Corp. - Warrants (delisted) | OACQW | |
| Orion Acquisition Corporation | OHPA | |
| Orion Biotech Opportunities Corporation | ORIA | |
| Orion Energy Systems Inc | OESX | |
| Orion Marine Grp. - Common (MM) | OMGI | |
| Orisun Acqusition Corporation | ORSN | |
| Oritani Financial (MM) | ORITD | |
| Oritani Financial Corporation | ORIT | |
| Orrstown Financial Services Inc | ORRF | |
| Ortho Clinical Diagnostics Holdings PLC | OCDX | |
| OrthoPediatrics Corporation | KIDS | |
| Orthofix Medical Inc | OFIX | |
| Orthologic (MM) | OLGC | |
| Orthovita, Inc. (MM) | VITA | |
| Oscient Pharmaceuticals (MM) | OSCID | |
| Oshkosh Bgosh Cla (MM) | GOSHA | |
| Osi Pharmaceuticals Inc. (MM) | OSIP | |
| Osiris Therape (MM) | OSIR | |
| Osmotica Pharmaceuticals PLC | OSMT | |
| Osprey Energy Acquisition Corp. (delisted) | OSPR | |
| Osprey Energy Acquisition Corp. - Unit (delisted) | OSPRU | |
| Osprey Energy Acquisition Corp. - Warrant (delisted) | OSPRW | |
| Osteotech Com (MM) | OSTE | |
| Otelco - Income Deposit Securities (MM) | OTT | |
| Otelco Inc | OTEL | |
| Otix Global (MM) | OTIX | |
| Otix Global, (MM) | OTIXD | |
| Otonomo Technologies Ltd | OTMO | |
| Otonomy Inc | OTIC | |
| Ottawa Savings Bancorp Inc | OTTW | |
| Otter Tail Corporation | OTTR | |
| Outbrain Inc | OB | |
| Outdoor Channel Holdings, Inc. (MM) | OUTD | |
| Outerwall Inc. (MM) | OUTR | |
| Outerwall Inc. - When Distributed (MM) | OUTRV | |
| Outlook (MM) | OUTL | |
| Outlook Therapeutics Inc | OTLK | |
| Outset Medical Inc | OM | |
| Ovascience Inc. (delisted) | OVAS | |
| Overland Storage (MM) | OVRLD | |
| Overnite Corp (MM) | OVNT | |
| Overstock com Inc | OSTK | |
| Overture Services Inc. (MM) | OVER | |
| Ovid Therapeutics Inc | OVID | |
| Oxbridge Re Holdings Ltd | OXBR | |
| Oxford Immunotec Global PLC | OXFD | |
| Oxford Lane Capital (MM) | OXLCR | |
| Oxford Lane Capital Corporation | OXLC | |
| Oxford Square Capital Corporation | OXSQG | |
| Oxford Square Capital Corporation | OXSQZ | |
| Oxford Square Capital Corporation | OXSQ | |
| Oxford Square Capital Corporation | OXSQA | |
| Oxford Square Capital Corporation | OXSQL | |
| Oxigene (MM) | OXGNW | |
| Oxigene, Inc. (MM) | OXGND | |
| Oyster Enterprises Acquisition Corporation | OSTR | |
| Oyster Point Pharma Inc | OYST | |
