| OAP3 | Octopus Apollo Vct Plc | 46.50 | 46.50 | 46.50 | 0 | 0.00 | | 0.00 | |
| OAUE | UBS Etf | 42.76 | 42.76 | 42.76 | 14 | 0.00 | | 0.00 | |
| OBD | Oxford Biodynamics Plc | 0.4500 | 0.4250 | 0.4250 | 2.45M | 0.0000 | | 0.00 | |
| OBI | Ondine Biomedical Inc | 16.00 | 15.11 | 15.50 | 107.5K | 0.00 | | 0.00 | |
| OCDO | Ocado Group Plc | 316.4 | 300.0 | 300.0 | 3.02M | -6.1 | | 1.99 | |
| OCI | Oakley Capital Investments Limited | 570.3 | 562.0 | 562.0 | 297.7K | -6.0 | | 1.06 | |
| OCN | Ocean Wilsons [Holdings] Ld | 1,225 | 1,197 | 1,225 | 22.1K | 5 | | 0.41 | |
| 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 | 0 | 0.000 | | 0.00 | |
| OGG9 | Gold Bullion Securities LD | 267.0 | 267.0 | 267.0 | 3.6K | 0.0 | | 0.00 | |
| OGLD | Deutsche Boerse Commodities Gmbh | 100.00 | 99.33 | 99.62 | 1.4K | -0.29 | | 0.29 | |
| OGN | Origin Enterprises Plc | 3.825 | 3.825 | 3.825 | 0 | 0.025 | | 0.66 | |
| OGOL | Global X Metal Securities | 39.20 | 39.20 | 39.20 | 214 | -11.42 | | 22.55 | |
| OGZU | ETFS Metal Securities Limited | 297.2 | 296.0 | 296.4 | 100 | -1.1 | | 0.38 | |
| OHGR | One Health Group PLC | 260.6 | 259.1 | 260.0 | 1.1K | 2.0 | | 0.78 | |
| OI20 | Kingdom Of Saudi Arabia (The) | 105.2 | 105.2 | 105.2 | 1.1M | 0.0 | | 0.00 | |
| OIG | Oryx International Growth Fund Ltd | 1,347 | 1,326 | 1,330 | 6.4K | -30 | | 2.21 | |
| OIGB | Vaneck Ucits Etfs PLC | 15.25 | 15.16 | 15.25 | 1.2K | 0.36 | | 2.40 | |
| OIH | Orascom Investment Holding S.A.E | 0.0150 | 0.0140 | 0.0140 | 1.8K | 0.0000 | | 0.00 | |
| OIHV | Vaneck Ucits Etfs PLC | 20.77 | 20.60 | 20.77 | 131 | 0.54 | | 2.67 | |
| OIL2 | Wisdomtree Commodity Securities Limited | 748.8 | 719.4 | 719.4 | 100 | -25.3 | | 3.39 | |
| OIL3 | UBS Ag | 86.36 | 86.36 | 86.36 | 0 | -1.35 | | 1.54 | |
| OILG | UBS Ag | 7,844 | 7,844 | 7,844 | 0 | -111 | | 1.40 | |
| OILU | UBS Ag | 128.3 | 128.3 | 128.3 | 0 | -1.9 | | 1.42 | |
| OIP9 | Shell International Finance B.V | 97.87 | 97.87 | 97.87 | 300K | 0.00 | | 0.00 | |
| OIT | Odyssean Investment Trust Plc | 159.5 | 157.0 | 159.5 | 136.1K | 0.5 | | 0.31 | |
| OM9S | Yorkshire Water Finance PLC | 69.60 | 69.60 | 69.60 | 100K | 0.00 | | 0.00 | |
| OMG | Omg Plc | 40.48 | 39.20 | 39.80 | 1.01M | -0.40 | | 1.00 | |
| OMI | Orosur Mining Inc | 23.50 | 21.33 | 21.60 | 4M | -1.15 | | 5.05 | |
| OMIP | One Media Ip Group Plc | 4.500 | 4.250 | 4.250 | 100 | 0.000 | | 0.00 | |
| OMU | Old Mutual Ltd | 60.40 | 57.80 | 59.80 | 233.8K | 0.80 | | 1.36 | |
| OMXS | Ishares IV Plc | 712.3 | 702.8 | 709.0 | 16.6K | 1.1 | | 0.16 | |
| ONDO | Ondo InsurTech PLC | 31.50 | 29.55 | 31.00 | 630.3K | 0.80 | | 2.65 | |
| ONT | Online Travel | 176.8 | 169.2 | 170.0 | 2.95M | -4.3 | | 2.47 | |
| ONWD | Onward Opportunities Ltd | 129.3 | 127.3 | 128.5 | 3.5K | 0.0 | | 0.00 | |
| OOA | Octopus Aim Vct Plc | 46.00 | 46.00 | 46.00 | 0 | 0.00 | | 0.00 | |
| OPEN | Ishares IV Plc | 9.678 | 9.673 | 9.673 | 1.1K | 0.046 | | 0.48 | |
| OPG | Opg Power Ventures Plc | 7.500 | 7.100 | 7.300 | 318.1K | 0.200 | | 2.82 | |
| OPT | Ocean Power Technologies Inc Com Shs | 225.0 | 218.0 | 222.5 | 53.5K | 1.5 | | 0.68 | |
| OPTI | Optibiotix Health Plc | 10.50 | 10.11 | 10.25 | 39.6K | 0.00 | | 0.00 | |
| 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 | 8.500 | 8.500 | 8.500 | 0 | 0.000 | | 0.00 | |
| ORCH | Orchard Funding Group Pl | 55.00 | 52.22 | 55.00 | 31.3K | 1.00 | | 1.85 | |
| ORCP | Oracle Coalfields Plc | 0.0170 | 0.0140 | 0.0150 | 637.06M | -0.0010 | | 6.25 | |
| ORIT | Octopus Renewables Infrastructure Trust | 67.60 | 65.50 | 67.10 | 612.1K | 0.60 | | 0.90 | |
| ORNT | Orient Telecoms Plc | 4.000 | 4.000 | 4.000 | 0 | 0.000 | | 0.00 | |
| ORR | Oriole Resources Plc | 0.4250 | 0.3700 | 0.3800 | 33.41M | 0.0000 | | 0.00 | |
| OS73 | Toyota Finance Australia Limited | 95.00 | 95.00 | 95.00 | 1M | 0.00 | | 0.00 | |
| OSB | Onesavings Bank Plc | 554.0 | 539.8 | 554.0 | 808K | 12.5 | | 2.31 | |
| OSEC | Octopus Second Aim Vct Plc | 36.40 | 36.40 | 36.40 | 0 | -0.20 | | 0.55 | |
| 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 | 14.50 | 14.50 | 14.50 | 0 | 0.00 | | 0.00 | |
| OT3 | Oxford Technology 2 Venture Capital | 7.000 | 7.000 | 7.000 | 0 | 0.000 | | 0.00 | |
| OT4 | Oxford Technology 2 Venture Capital | 6.500 | 6.500 | 6.500 | 0 | 0.000 | | 0.00 | |
| OTB | On The Beach Group Plc | 268.5 | 261.5 | 267.0 | 204.9K | 3.5 | | 1.33 | |
| 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 | 0 | 0.00 | | 0.00 | |
| OTV2 | Octopus Titan Vct Plc | 28.50 | 23.00 | 28.50 | 23K | 0.00 | | 0.00 | |
| OUFU | Ossiam Irl Icav | 204.5 | 204.5 | 204.5 | 0 | 2.4 | | 1.19 | |
| OVB | Ovoca Bio Plc | 1.295 | 1.045 | 1.150 | 173.3K | 0.000 | | 0.00 | |
| OVCT | Octopus Vct Plc | 22.90 | 22.90 | 22.90 | 0 | 0.00 | | 0.00 | |
| OVZA | ETFS Metal Securities Limited | 108.6 | 108.0 | 108.4 | 100 | 0.1 | | 0.08 | |
| OVZB | ETFS Metal Securities Limited | 93.10 | 91.84 | 92.79 | 2K | -0.13 | | 0.14 | |
| OVZC | ETFS Metal Securities Limited | 32.22 | 32.02 | 32.22 | 100 | 0.18 | | 0.55 | |
| OXA1 | DB Etc Plc | 210.6 | 209.2 | 210.6 | 11.5K | -0.6 | | 0.28 | |
| OXA2 | DB Etc Plc | 219.1 | 217.6 | 219.1 | 12.5K | 0.6 | | 0.27 | |
| OXA5 | DB Etc Plc | 298.2 | 296.8 | 297.2 | 229 | -1.2 | | 0.40 | |
| OXA6 | DB Etc Plc | 331.1 | 328.1 | 328.1 | 100 | -2.0 | | 0.60 | |
| OXB | Oxford Biomedica Plc | 605.0 | 594.0 | 600.0 | 146.3K | -2.0 | | 0.33 | |
| OXH | Oxford Technology 2 Venture Capital Trus | 5.500 | 5.500 | 5.500 | 0 | 0.000 | | 0.00 | |
| OXIG | Oxford Instruments Plc | 1,860 | 1,814 | 1,852 | 78.9K | 26 | | 1.42 | |
| OZ76 | Nationwide Building Society | 98.25 | 98.25 | 98.25 | 578K | 0.00 | | 0.00 | |