| OAP3 | Octopus Apollo Vct PLC | 47.10 | 47.10 | 47.10 | 0 | -1.50 | | 3.09 | |
| OAUE | UBS Etf | 42.76 | 42.76 | 42.76 | 73 | 0.00 | | 0.00 | |
| OBD | Oxford Biodynamics PLC | 0.2850 | 0.2730 | 0.2750 | 24.41M | -0.0010 | | 0.36 | |
| OBI | Ondine Biomedical Inc. | 12.00 | 11.00 | 11.25 | 343.9K | -0.30 | | 2.60 | |
| OCDO | Ocado Group PLC | 216.5 | 166.0 | 179.9 | 13.55M | -37.9 | | 17.40 | |
| OCI | Oakley Capital Investments Limited | 576.0 | 564.0 | 564.0 | 155.2K | -4.0 | | 0.71 | |
| OCN | Ocean Wilsons (Holdings) LD | 1,135 | 1,115 | 1,115 | 35.5K | -15 | | 1.32 | |
| OCTF | First Trust Global Funds Public Limited | 2,026 | 2,026 | 2,026 | 0 | -11 | | 0.55 | |
| OE08 | Bank Of Montreal | 100.4 | 100.4 | 100.4 | 1.0M | 0.0 | | 0.00 | |
| OE61 | The Kingdom Of Morocco | 108.8 | 108.8 | 108.8 | 550.0K | 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 | 0 | 0.000 | | 0.00 | |
| OGG9 | Gold Bullion Securities LD | 331.0 | 329.6 | 331.0 | 3.8K | 13.0 | | 4.10 | |
| OGLD | Deutsche Boerse Commodities Gmbh | 116.3 | 111.4 | 112.9 | 5.1K | 0.1 | | 0.06 | |
| OGN | Origin Enterprises PLC | 3.730 | 3.730 | 3.730 | 0 | 0.000 | | 0.00 | |
| OGOL | Global X Metal Securities | 56.35 | 56.35 | 56.35 | 110 | 0.00 | | 0.00 | |
| OGZU | Wisdomtree Metal Securities Limited | 347.5 | 331.5 | 335.4 | 3.6K | 0.3 | | 0.10 | |
| OHGR | One Health Group PLC | 228.0 | 228.0 | 228.0 | 0 | -4.0 | | 1.72 | |
| OI20 | Kingdom Of Saudi Arabia (The) | 106.2 | 106.2 | 106.2 | 2.68M | 0.0 | | 0.00 | |
| OIG | Oryx International Growth Fund LTD | 1,280 | 1,220 | 1,250 | 455 | 25 | | 2.04 | |
| OIGB | Vaneck Ucits Etfs PLC | 17.06 | 16.91 | 17.06 | 943 | -0.29 | | 1.67 | |
| OIH | Orascom Investment Holding S.A.E | 0.0150 | 0.0140 | 0.0140 | 1.8K | 0.0000 | | 0.00 | |
| OIHV | Vaneck Ucits Etfs PLC | 22.42 | 22.30 | 22.42 | 875 | -0.55 | | 2.39 | |
| OIL2 | Wisdomtree Commodity Securities Limited | 691.0 | 681.3 | 690.8 | 112 | 2.3 | | 0.33 | |
| OIL3 | UBS AG | 84.08 | 84.08 | 84.08 | 0 | -0.16 | | 0.19 | |
| OILG | UBS AG | 7,624 | 7,624 | 7,624 | 0 | -12 | | 0.16 | |
| OILU | UBS AG | 124.9 | 124.9 | 124.9 | 0 | -0.2 | | 0.18 | |
| OIP9 | Shell International Finance B.V | 98.24 | 98.24 | 98.24 | 300.0K | 0.00 | | 0.00 | |
| OIT | Odyssean Investment Trust PLC | 169.5 | 162.7 | 164.5 | 176.6K | -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 | 43.90 | 41.80 | 42.60 | 128.1K | 0.19 | | 0.45 | |
| OMI | Orosur Mining INC | 20.00 | 18.50 | 19.00 | 870.8K | -0.35 | | 1.81 | |
| OMIP | One Media Ip Group PLC | 3.975 | 3.750 | 3.750 | 125 | 0.000 | | 0.00 | |
| OMU | Old Mutual Limited | 62.00 | 59.55 | 60.60 | 186.3K | -1.40 | | 2.26 | |
| OMXS | Ishares Iv PLC | 735.8 | 720.3 | 722.8 | 140.6K | -19.7 | | 2.65 | |
| ONDO | Ondo Insurtech PLC | 32.00 | 31.00 | 31.00 | 937.6K | -0.20 | | 0.64 | |
| ONT | Oxford Nanopore Technologies PLC | 126.4 | 122.1 | 123.6 | 939.6K | -4.1 | | 3.21 | |
| ONWD | Onward Opportunities Limited | 135.6 | 133.0 | 135.0 | 3.8K | -2.0 | | 1.46 | |
| OOA | Octopus Aim Vct PLC | 46.40 | 46.40 | 46.40 | 0 | 0.00 | | 0.00 | |
| OPEN | Ishares Iv PLC | 9.581 | 9.515 | 9.551 | 112 | -0.155 | | 1.60 | |
| OPG | Opg Power Ventures PLC | 5.980 | 5.900 | 5.900 | 629.7K | 0.000 | | 0.00 | |
| OPT | Optima Health PLC | 204.0 | 200.0 | 202.5 | 368.9K | -0.9 | | 0.44 | |
| OPTI | Optibiotix Health PLC | 8.500 | 7.800 | 7.900 | 331.1K | -0.337 | | 4.09 | |
| 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 | 16.50 | 14.50 | 15.50 | 40.1K | 1.00 | | 6.90 | |
| ORCH | Orchard Funding Group PLC | 58.00 | 56.00 | 58.00 | 2.0K | -1.00 | | 1.69 | |
| ORCP | Oracle Power PLC | 0.0400 | 0.0320 | 0.0350 | 218.03M | -0.0010 | | 2.78 | |
| ORIT | Octopus Renewables Infrastructure Trust | 58.93 | 57.80 | 58.00 | 1.18M | -0.80 | | 1.36 | |
| ORNT | Orient Telecoms PLC | 4.000 | 4.000 | 4.000 | 0 | 0.000 | | 0.00 | |
| ORR | Oriole Resources PLC | 0.2440 | 0.2300 | 0.2440 | 14.09M | 0.0040 | | 1.67 | |
| OS73 | Toyota Finance Australia Limited | 95.00 | 95.00 | 95.00 | 1.0M | 0.00 | | 0.00 | |
| OSB | Osb Group PLC | 545.0 | 535.0 | 538.0 | 813.6K | -6.5 | | 1.19 | |
| OSEC | Octopus Aim Vct 2 PLC | 35.00 | 35.00 | 35.00 | 0 | 0.00 | | 0.00 | |
| OSX5 | Source Markets Public Limited Company | 54.25 | 54.25 | 54.25 | 0 | -1.24 | | 2.23 | |
| 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 | 4.500 | 6.500 | 5.2K | 0.000 | | 0.00 | |
| OTB | On The Beach Group PLC | 202.8 | 193.0 | 195.0 | 969.1K | -11.0 | | 5.34 | |
| 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 | 24.50 | 24.50 | 24.50 | 0 | 0.00 | | 0.00 | |
| OUFU | Ossiam Irl Icav | 207.1 | 207.1 | 205.2 | 3 | -1.0 | | 0.49 | |
| OVB | Ovoca Bio PLC | 1.295 | 1.045 | 1.150 | 173.3K | 0.000 | | 0.00 | |
| OVCT | Oberon Aim Vct PLC | 25.10 | 25.10 | 25.10 | 0 | 1.10 | | 4.58 | |
| OVZA | Wisdomtree Metal Securities Limited | 121.7 | 119.6 | 121.2 | 100 | 0.2 | | 0.15 | |
| OVZB | Wisdomtree Metal Securities Limited | 111.1 | 109.1 | 109.4 | 100 | 0.2 | | 0.20 | |
| OVZC | Wisdomtree Metal Securities Limited | 39.99 | 39.18 | 39.63 | 40.1K | -0.28 | | 0.71 | |
| OXA1 | Db Etc PLC | 240.7 | 231.4 | 233.6 | 32.1K | -1.0 | | 0.41 | |
| OXA2 | Db Etc PLC | 270.3 | 264.2 | 267.0 | 1.1K | -1.3 | | 0.49 | |
| OXA5 | Db Etc PLC | 347.1 | 332.4 | 336.7 | 882 | -1.0 | | 0.30 | |
| OXA6 | Db Etc PLC | 418.4 | 403.3 | 410.7 | 309 | 0.8 | | 0.20 | |
| OXB | Oxford Biomedica PLC | 620.0 | 594.0 | 599.0 | 105.4K | -15.4 | | 2.50 | |
| OXH | Oxford Technology 2 Venture Capital | 6.000 | 6.000 | 6.000 | 0 | 0.000 | | 0.00 | |
| OXIG | Oxford Instruments PLC | 2,030 | 1,940 | 1,982 | 177.0K | -53 | | 2.60 | |
| OZ76 | Nationwide Building Society | 98.25 | 98.25 | 98.25 | 578.0K | 0.00 | | 0.00 | |