| OAP3 | Octopus Apollo Vct Plc | 48.00 | 39.00 | 46.50 | 135.5K | 0.00 | | 0.00 | |
| OAUE | UBS Etf | 42.76 | 42.76 | 42.76 | 14 | 0.00 | | 0.00 | |
| OBD | Oxford Biodynamics Plc | 0.4500 | 0.4310 | 0.4500 | 4.35M | 0.0250 | | 5.88 | |
| OBI | Ondine Biomedical Inc. | 15.70 | 15.00 | 15.00 | 283.3K | -0.50 | | 3.23 | |
| OCDO | Ocado Group Plc | 297.9 | 240.3 | 270.7 | 15.99M | -29.3 | | 9.76 | |
| OCI | Oakley Capital Investments Limited | 570.0 | 560.0 | 565.0 | 124.8K | 3.0 | | 0.53 | |
| OCN | Ocean Wilsons [Holdings] Ld | 1,225 | 1,209 | 1,215 | 65.5K | -10 | | 0.82 | |
| OE08 | Bank Of Montreal | 100.4 | 100.4 | 100.4 | 1M | 0.0 | | 0.00 | |
| OE61 | The Kingdom Of Morocco | 106.6 | 106.6 | 106.6 | 503K | 0.0 | | 0.00 | |
| OFG | Octopus Future Generations Vct PLC | 79.50 | 79.50 | 79.50 | 0 | 0.00 | | 0.00 | |
| OGDC | Oil and Gas Development | 8.000 | 8.000 | 8.000 | 6K | 0.000 | | 0.00 | |
| OGG9 | Gold Bullion Securities LD | 285.2 | 285.1 | 285.1 | 100 | 18.1 | | 6.78 | |
| OGLD | Deutsche Boerse Commodities Gmbh | 100.3 | 99.9 | 100.0 | 6K | 0.4 | | 0.39 | |
| OGN | Origin Enterprises Plc | 3.700 | 3.700 | 3.825 | 148 | 0.000 | | 0.00 | |
| OGOL | Global X Metal Securities | 39.20 | 39.20 | 39.20 | 214 | 0.00 | | 0.00 | |
| OGZU | ETFS Metal Securities Limited | 298.4 | 297.4 | 297.7 | 0 | 1.2 | | 0.41 | |
| OHGR | One Health Group PLC | 262.0 | 253.3 | 254.6 | 46.9K | -5.4 | | 2.09 | |
| OI20 | Kingdom Of Saudi Arabia (The) | 105.2 | 105.2 | 105.2 | 1.1M | 0.0 | | 0.00 | |
| OIG | Oryx International Growth Fund Ltd | 1,395 | 1,320 | 1,320 | 3.9K | -10 | | 0.74 | |
| OIGB | Vaneck Ucits Etfs PLC | 15.18 | 15.06 | 15.06 | 1.1K | -0.19 | | 1.25 | |
| OIH | Orascom Investment Holding S.A.E | 0.0150 | 0.0140 | 0.0140 | 1.8K | 0.0000 | | 0.00 | |
| OIHV | Vaneck Ucits Etfs PLC | 20.57 | 20.57 | 20.57 | 100 | -0.20 | | 0.96 | |
| OIL2 | Wisdomtree Commodity Securities Limited | 751.3 | 703.8 | 742.5 | 264 | 23.1 | | 3.21 | |
| OIL3 | UBS Ag | 86.17 | 86.17 | 87.56 | 0 | -1.35 | | 1.59 | |
| OILG | UBS Ag | 7,872 | 7,872 | 7,947 | 1 | 103 | | 1.31 | |
| OILU | UBS Ag | 129.9 | 129.9 | 130.0 | 75 | -1.9 | | 1.47 | |
| OIP9 | Shell International Finance B.V | 97.87 | 97.87 | 97.87 | 300K | 0.00 | | 0.00 | |
| OIT | Odyssean Investment Trust Plc | 158.7 | 157.0 | 157.0 | 84.4K | -2.5 | | 1.57 | |
| OM9S | Yorkshire Water Finance PLC | 69.60 | 69.60 | 69.60 | 100K | 0.00 | | 0.00 | |
| OMG | Omg Plc | 39.73 | 39.00 | 39.00 | 329.6K | -0.80 | | 2.01 | |
| OMI | Orosur Mining Inc | 24.00 | 22.25 | 22.47 | 4.06M | 0.87 | | 4.03 | |
| OMIP | One Media Ip Group Plc | 4.500 | 3.500 | 4.500 | 627 | 0.250 | | 5.88 | |
| OMU | Old Mutual Ltd | 60.40 | 58.40 | 59.00 | 106K | -0.80 | | 1.34 | |
| OMXS | Ishares IV Plc | 710.0 | 707.3 | 708.7 | 7.5K | -0.3 | | 0.04 | |
| ONDO | Ondo Insurtech PLC | 32.50 | 30.50 | 32.50 | 561K | 1.50 | | 4.84 | |
| ONT | Online Travel | 170.9 | 164.1 | 166.5 | 1.52M | -3.5 | | 2.05 | |
| ONWD | Onward Opportunities Ltd | 129.3 | 127.7 | 127.7 | 22.9K | -0.8 | | 0.65 | |
| OOA | Octopus Aim Vct Plc | 47.40 | 44.60 | 47.40 | 4.7K | 1.40 | | 3.04 | |
| OPEN | Ishares IV Plc | 9.710 | 9.687 | 9.687 | 6.7K | 0.014 | | 0.14 | |
| OPG | Opg Power Ventures Plc | 7.540 | 7.220 | 7.220 | 262.7K | -0.080 | | 1.10 | |
| OPT | Ocean Power Technologies Inc Com Shs | 228.0 | 221.2 | 222.1 | 139.1K | -0.4 | | 0.18 | |
| OPTI | Optibiotix Health Plc | 10.500 | 10.000 | 10.000 | 151.2K | -0.250 | | 2.44 | |
| OQ12 | Standard Chartered PLC | 91.65 | 91.65 | 91.65 | 900K | 0.00 | | 0.00 | |
| ORC1 | Orchard Bond Finance PLC | 99.3 | 99.3 | 101.8 | 6.6K | 0.0 | | 0.00 | |
| ORCA | Orca Interact | 8.570 | 8.000 | 8.130 | 6.5K | -0.370 | | 4.35 | |
| ORCH | Orchard Funding Group Pl | 57.00 | 53.60 | 53.60 | 4.9K | -1.40 | | 2.55 | |
| ORCP | Oracle Coalfields Plc | 0.0160 | 0.0140 | 0.0150 | 566.35M | 0.0000 | | 0.00 | |
| ORIT | Octopus Renewables Infrastructure Trust | 67.60 | 65.90 | 66.50 | 743.2K | -0.60 | | 0.89 | |
| ORNT | Orient Telecoms Plc | 4.500 | 4.500 | 4.000 | 2.1K | 0.000 | | 0.00 | |
| ORR | Oriole Resources Plc | 0.4200 | 0.3520 | 0.3720 | 62.71M | -0.0080 | | 2.11 | |
| OS73 | Toyota Finance Australia Limited | 95.00 | 95.00 | 95.00 | 1M | 0.00 | | 0.00 | |
| OSB | Onesavings Bank Plc | 557.5 | 550.5 | 553.5 | 512.7K | -0.5 | | 0.09 | |
| OSEC | Octopus Second Aim Vct Plc | 37.60 | 36.00 | 36.40 | 236.4K | 0.00 | | 0.00 | |
| OSX5 | Source Markets Public Limited Company | 53.10 | 53.10 | 53.10 | 0 | 0.00 | | 0.00 | |
| OT06 | Derwent London PLC | 72.10 | 72.10 | 72.10 | 9.6K | 0.00 | | 0.00 | |
| OT1 | Oxford Technology 2 Venture Capital | 15.00 | 11.00 | 14.50 | 22K | 0.00 | | 0.00 | |
| OT3 | Oxford Technology 2 Venture Capital | 8.500 | 8.500 | 7.000 | 50K | 0.000 | | 0.00 | |
| OT4 | Oxford Technology 2 Venture Capital | 8.000 | 8.000 | 6.500 | 50K | 0.000 | | 0.00 | |
| OTB | On The Beach Group Plc | 268.0 | 263.0 | 264.0 | 154K | -3.0 | | 1.12 | |
| OTES | Hellenic Telecommunications Organization | 9.440 | 9.440 | 9.440 | 8 | 0.000 | | 0.00 | |
| OTPD | Otp Bank Plc | 17.00 | 17.00 | 17.00 | 1 | 0.00 | | 0.00 | |
| OTV2 | Octopus Titan Vct Plc | 23.00 | 23.00 | 27.50 | 23K | 0.00 | | 0.00 | |
| OUFU | Ossiam Irl Icav | 202.8 | 202.8 | 204.2 | 58 | 2.4 | | 1.18 | |
| OVB | Ovoca Bio Plc | 1.295 | 1.045 | 1.150 | 173.3K | 0.000 | | 0.00 | |
| OVCT | Octopus Vct Plc | 22.00 | 22.00 | 22.90 | 1K | 0.00 | | 0.00 | |
| OVZA | ETFS Metal Securities Limited | 109.7 | 108.4 | 109.2 | 100 | 0.9 | | 0.78 | |
| OVZB | ETFS Metal Securities Limited | 96.39 | 93.74 | 94.71 | 100 | 1.92 | | 2.07 | |
| OVZC | ETFS Metal Securities Limited | 33.04 | 32.70 | 32.87 | 100 | 0.65 | | 2.03 | |
| OXA1 | DB Etc Plc | 211.5 | 210.8 | 211.2 | 100 | 0.7 | | 0.31 | |
| OXA2 | DB Etc Plc | 225.0 | 223.8 | 224.4 | 100 | 5.3 | | 2.42 | |
| OXA5 | DB Etc Plc | 299.4 | 298.1 | 299.0 | 100 | 1.8 | | 0.60 | |
| OXA6 | DB Etc Plc | 338.8 | 336.0 | 338.5 | 100 | 10.4 | | 3.17 | |
| OXB | Oxford Biomedica Plc | 605.0 | 578.0 | 578.0 | 369.7K | -22.0 | | 3.67 | |
| OXH | Oxford Technology 2 Venture Capital Trus | 3.500 | 3.500 | 5.500 | 3.3K | 0.000 | | 0.00 | |
| OXIG | Oxford Instruments Plc | 1,846 | 1,812 | 1,822 | 69.2K | -30 | | 1.62 | |
| OZ76 | Nationwide Building Society | 98.25 | 98.25 | 98.25 | 578K | 0.00 | | 0.00 | |