| OAP3 | Octopus Apollo Vct PLC | 47.98 | 47.50 | 47.98 | 25.08M | 1.48 | | 3.18 | |
| OAUE | UBS Etf | 42.76 | 42.76 | 42.76 | 102 | 0.00 | | 0.00 | |
| OBD | Oxford Biodynamics PLC | 0.3300 | 0.3030 | 0.3200 | 34.96M | 0.0010 | | 0.31 | |
| OBI | Ondine Biomedical Inc. | 13.50 | 13.00 | 13.24 | 326.3K | -0.26 | | 1.93 | |
| OCDO | Ocado Group PLC | 220.9 | 215.4 | 219.1 | 4.25M | -0.9 | | 0.41 | |
| OCI | Oakley Capital Investments Limited | 562.0 | 556.0 | 560.0 | 713.7K | 4.0 | | 0.73 | |
| OCN | Ocean Wilsons (Holdings) LD | 1,175 | 1,125 | 1,157 | 52.9K | 27 | | 2.36 | |
| OCTF | First Trust Global Funds Public Limited | 2,026 | 2,026 | 2,062 | 150 | 1 | | 0.06 | |
| OE08 | Bank Of Montreal | 100.4 | 100.4 | 100.4 | 1.0M | 0.0 | | 0.00 | |
| OE61 | The Kingdom Of Morocco | 110.4 | 110.4 | 110.4 | 450.0K | 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 Company Limited | 8.000 | 8.000 | 8.000 | 6.0K | 0.000 | | 0.00 | |
| OGG9 | Gold Bullion Securities LD | 313.3 | 313.3 | 313.3 | 51 | 0.0 | | 0.00 | |
| OGLD | Deutsche Boerse Commodities Gmbh | 112.2 | 111.0 | 111.1 | 2.5K | 0.1 | | 0.05 | |
| OGN | Origin Enterprises PLC | 3.765 | 3.755 | 3.760 | 82 | 0.000 | | 0.00 | |
| OGOL | Global X Metal Securities | 39.20 | 39.20 | 39.20 | 221 | 0.00 | | 0.00 | |
| OGZU | Wisdomtree Metal Securities Limited | 333.5 | 331.1 | 333.5 | 0 | 2.0 | | 0.61 | |
| OHGR | One Health Group PLC | 239.9 | 233.0 | 233.0 | 14.7K | -6.0 | | 2.51 | |
| OI20 | Kingdom Of Saudi Arabia (The) | 105.9 | 105.9 | 105.9 | 1.16M | 0.0 | | 0.00 | |
| OIG | Oryx International Growth Fund LTD | 1,309 | 1,295 | 1,309 | 5.2K | 1 | | 0.11 | |
| OIGB | Vaneck Ucits Etfs PLC | 17.48 | 17.09 | 17.17 | 100.8K | -0.33 | | 1.89 | |
| OIH | Orascom Investment Holding S.A.E | 0.0150 | 0.0140 | 0.0140 | 1.8K | 0.0000 | | 0.00 | |
| OIHV | Vaneck Ucits Etfs PLC | 22.86 | 22.55 | 22.61 | 3.7K | -0.42 | | 1.80 | |
| OIL2 | Wisdomtree Commodity Securities Limited | 720.0 | 691.0 | 712.5 | 222 | 10.5 | | 1.50 | |
| OIL3 | UBS AG | 86.17 | 86.17 | 84.39 | 0 | -0.21 | | 0.26 | |
| OILG | UBS AG | 7,466 | 7,466 | 7,674 | 0 | -26 | | 0.35 | |
| OILU | UBS AG | 129.9 | 129.9 | 125.7 | 75 | -0.2 | | 0.12 | |
| OIP9 | Shell International Finance B.V | 98.24 | 98.24 | 98.24 | 300.0K | 0.00 | | 0.00 | |
| OIT | Odyssean Investment Trust PLC | 165.5 | 165.0 | 165.0 | 157.4K | -1.0 | | 0.60 | |
| OM9S | Yorkshire Water Finance PLC | 69.60 | 69.60 | 69.60 | 100.0K | 0.00 | | 0.00 | |
| OMG | Oxford Metrics PLC | 45.40 | 43.10 | 44.17 | 121.8K | 0.67 | | 1.54 | |
| OMI | Orosur Mining INC | 22.50 | 21.00 | 21.65 | 1.67M | 0.15 | | 0.70 | |
| OMIP | One Media Ip Group PLC | 3.900 | 3.550 | 3.550 | 90.7K | -0.200 | | 5.33 | |
| OMU | Old Mutual Limited | 60.00 | 58.80 | 58.80 | 96.2K | 0.40 | | 0.68 | |
| OMXS | Ishares Iv PLC | 760.5 | 750.4 | 750.4 | 6.4K | -9.4 | | 1.23 | |
| ONDO | Ondo Insurtech PLC | 31.12 | 28.50 | 31.00 | 1.15M | 1.50 | | 5.08 | |
| ONT | Oxford Nanopore Technologies PLC | 138.0 | 134.8 | 136.9 | 1.59M | 0.4 | | 0.26 | |
| ONWD | Onward Opportunities Limited | 139.0 | 135.0 | 139.0 | 14.1K | 2.0 | | 1.46 | |
| OOA | Octopus Aim Vct PLC | 45.80 | 45.00 | 46.40 | 76.6K | 0.00 | | 0.00 | |
| OPEN | Ishares Iv PLC | 9.697 | 9.697 | 9.697 | 346 | -0.027 | | 0.28 | |
| OPG | Opg Power Ventures PLC | 5.600 | 5.485 | 5.511 | 305.3K | 0.061 | | 1.12 | |
| OPT | Optima Health PLC | 201.0 | 197.0 | 199.9 | 567.4K | 2.4 | | 1.19 | |
| OPTI | Optibiotix Health PLC | 8.500 | 7.633 | 8.000 | 1.09M | -0.250 | | 3.03 | |
| OQ12 | Standard Chartered PLC | 92.69 | 92.69 | 92.69 | 1.63M | 0.00 | | 0.00 | |
| ORC1 | Orchard Bond Finance PLC | 99.3 | 99.3 | 101.8 | 6.6K | 0.0 | | 0.00 | |
| ORCA | Orcadian Energy PLC | 17.00 | 15.50 | 16.80 | 406.6K | 0.30 | | 1.82 | |
| ORCH | Orchard Funding Group PLC | 60.00 | 58.20 | 60.00 | 69.6K | 1.00 | | 1.69 | |
| ORCP | Oracle Power PLC | 0.0450 | 0.0380 | 0.0440 | 69.87M | 0.0010 | | 2.33 | |
| ORIT | Octopus Renewables Infrastructure Trust | 61.80 | 58.03 | 58.40 | 2.26M | -2.10 | | 3.47 | |
| ORNT | Orient Telecoms PLC | 3.220 | 3.200 | 4.000 | 15.0K | 0.000 | | 0.00 | |
| ORR | Oriole Resources PLC | 0.2900 | 0.2660 | 0.2700 | 37.8M | -0.0200 | | 6.90 | |
| OS73 | Toyota Finance Australia Limited | 95.00 | 95.00 | 95.00 | 1.0M | 0.00 | | 0.00 | |
| OSB | Osb Group PLC | 551.5 | 537.0 | 541.2 | 888.0K | -2.8 | | 0.51 | |
| OSEC | Octopus Aim Vct 2 PLC | 36.10 | 36.10 | 36.40 | 64.4K | 0.00 | | 0.00 | |
| OSX5 | Source Markets Public Limited Company | 55.44 | 55.43 | 55.43 | 100 | 0.23 | | 0.42 | |
| OT06 | Derwent London PLC | 72.10 | 72.10 | 72.10 | 9.6K | 0.00 | | 0.00 | |
| OT1 | Oxford Technology 2 Venture Capital | 12.00 | 12.00 | 14.50 | 70 | 0.00 | | 0.00 | |
| OT3 | Oxford Technology 2 Venture Capital | 5.000 | 5.000 | 7.000 | 2.8K | 0.000 | | 0.00 | |
| OT4 | Oxford Technology 2 Venture Capital | 4.500 | 4.500 | 6.500 | 3.5K | 0.000 | | 0.00 | |
| OTB | On The Beach Group PLC | 218.5 | 211.0 | 212.5 | 1.08M | -4.0 | | 1.85 | |
| 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 | 26.00 | 26.00 | 24.50 | 10.0K | 0.00 | | 0.00 | |
| OUFU | Ossiam Irl Icav | 202.9 | 201.8 | 205.1 | 57 | -0.6 | | 0.27 | |
| OVB | Ovoca Bio PLC | 1.295 | 1.045 | 1.150 | 173.3K | 0.000 | | 0.00 | |
| OVCT | Oberon Aim Vct PLC | 24.00 | 24.00 | 25.10 | 5.0K | 1.00 | | 4.33 | |
| OVZA | Wisdomtree Metal Securities Limited | 128.0 | 125.8 | 126.4 | 100 | 0.2 | | 0.17 | |
| OVZB | Wisdomtree Metal Securities Limited | 116.4 | 113.6 | 113.6 | 100 | -1.3 | | 1.09 | |
| OVZC | Wisdomtree Metal Securities Limited | 38.95 | 38.37 | 38.40 | 2.9K | -0.12 | | 0.32 | |
| OXA1 | Db Etc PLC | 232.2 | 230.7 | 232.2 | 322 | 1.5 | | 0.67 | |
| OXA2 | Db Etc PLC | 261.1 | 256.5 | 257.4 | 100 | -1.0 | | 0.37 | |
| OXA5 | Db Etc PLC | 334.8 | 332.0 | 333.9 | 100 | 2.5 | | 0.74 | |
| OXA6 | Db Etc PLC | 399.7 | 394.1 | 394.1 | 100 | 21.8 | | 5.85 | |
| OXB | Oxford Biomedica PLC | 670.0 | 656.0 | 658.4 | 153.2K | -0.6 | | 0.10 | |
| OXH | Oxford Technology 2 Venture Capital | 7.500 | 7.500 | 6.000 | 20.0K | 0.000 | | 0.00 | |
| OXIG | Oxford Instruments PLC | 1,982 | 1,864 | 1,898 | 99.0K | 6 | | 0.30 | |
| OZ76 | Nationwide Building Society | 98.25 | 98.25 | 98.25 | 578.0K | 0.00 | | 0.00 | |