| 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 | 0.3998 | 0.3450 | 0.3998 | 10.0K | 0.0198 | | 5.21 | |
| 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 | 0.9542 | 0.9542 | 0.9542 | 400 | 0.0004 | | 0.04 | |
| ORLCF | Oracle Commodity Hldg Crp | 0.0237 | 0.0220 | 0.0220 | 29.3K | -0.0027 | | 10.93 | |
| OTLC | Oncotelic Therapeutcs Inc | 0.0500 | 0.0450 | 0.0500 | 288.1K | 0.0015 | | 3.09 | |
| OTMCF | Romios Gold Resources Inc | 0.4400 | 0.4400 | 0.4400 | 11.9K | 0.0236 | | 5.67 | |
| OXFYY | Oxford Nanopre Tech U/Adr | 6.500 | 6.500 | 6.500 | 200 | -0.880 | | 11.92 | |
| OZSC | Ozop Energy Solutions Inc | 0.1900 | 0.1200 | 0.1600 | 5.5K | -0.0400 | | 20.00 | |