| OBGRF | Orbit Garant Drilling Inc | 0.9730 | 0.7000 | 0.8500 | 52.0K | -0.1455 | | 14.62 | |
| OERLY | Oc Oerlikon Corp Unsp/Adr | 9.600 | 9.600 | 9.600 | 900 | 0.700 | | 7.87 | |
| OFED | Oconee Federal Fincl Corp | 17.51 | 17.51 | 17.51 | 100 | -0.49 | | 2.72 | |
| OKCTF | Okinawa Cellular Tele Ord | 22.77 | 22.77 | 22.77 | 400 | -0.35 | | 1.25 | |
| OLVI | Oliveda International Inc | 0.3999 | 0.3500 | 0.3700 | 12.5K | -0.0298 | | 7.45 | |
| OLYFF | Olympia Financial Group Inc | 78.00 | 78.00 | 78.00 | 100 | 3.06 | | 4.08 | |
| OMHI | Om Holdings International Inc | 0.0002 | 0.0002 | 0.0002 | 7.0K | -0.0002 | | 50.00 | |
| OMMSF | Omineca Mining & Mtls Ord | 0.0514 | 0.0514 | 0.0514 | 24.0K | -0.0007 | | 1.34 | |
| ONVC | Online Vacation Ctr Hldgs | 2.050 | 2.050 | 2.050 | 1.0K | 0.050 | | 2.50 | |
| OPIRQ | Office Properties Income Trust 6.375% | 0.3100 | 0.3100 | 0.3100 | 400 | -0.7200 | | 69.90 | |
| OPITQ | Office Properties Income Trust | 0.0021 | 0.0010 | 0.0015 | 151.7K | -0.0010 | | 40.00 | |
| OPMXF | Operadora DE Sites Mexicn | 0.9522 | 0.9522 | 0.9522 | 700 | -0.0020 | | 0.21 | |
| ORLCF | Oracle Commodity Hldg Crp | 0.0240 | 0.0231 | 0.0231 | 2.0K | 0.0011 | | 5.00 | |
| OROVY | Orient Overseas Inr U/Adr | 78.40 | 78.20 | 78.20 | 1.1K | -11.51 | | 12.83 | |
| OTLC | Oncotelic Therapeutcs Inc | 0.0520 | 0.0450 | 0.0490 | 562.0K | -0.0010 | | 2.00 | |
| OTMCF | Romios Gold Resources Inc | 0.4066 | 0.4066 | 0.4066 | 5.1K | -0.0334 | | 7.59 | |
| OXFYY | Oxford Nanopre Tech U/Adr | 6.500 | 6.500 | 6.500 | 200 | -0.880 | | 11.92 | |
| OZSC | Ozop Energy Solutions Inc | 0.1900 | 0.1600 | 0.1900 | 9.5K | 0.0300 | | 18.75 | |