| 122 Leighton Road Limited | Households | 2004 |
| 122 Lexham Gardens Management Company Limited | Real estate | 1999 |
| 122 Lordship Road Freehold Limited | Real estate | 2016 |
| 122 LR Limited | Real estate | 2017 |
| 122 Lyndhurst Way Limited | Households | 2022 |
| 122 Manor Lane Limited | Extraterritorial | 2005 |
| 122 Melrose Avenue Freehold Limited | Households | 2026 |
| 122 Music Management Limited | Arts & recreation | 2023 |
| 122 Productions Limited | Other services | 2024 |
| 122 Saint Julian's Farm Road Residents Company Limited | Households | 2003 |
| 122 Services Ltd | Professional & scientific | 2026 |
| 122 Shirland Road Freehold Company Limited | Households | 2025 |
| 122 Sinclair Road Management Limited | Households | 2001 |
| 122 Stockwell Road Freehold Limited | Households | 2013 |
| 12211186 Ltd | Mining & quarrying | 2019 |
| 1227 Investments Ltd | Real estate | 2016 |
| 1228 Group Limited | Administrative & support | 2024 |
| 12287921 Limited | Financial services | 2019 |
| 123 -125 Charlton Road Freehold Company Ltd | Households | 2016 |
| 123 55 Ellesmere Road Limited | Households | 2026 |
| 123 AP Developments Limited | Construction | 2019 |
| 123 AP Limited | Administrative & support | 2019 |
| 123 Bakes Ltd | Hospitality | 2023 |
| 123 Brecknock Road Freehold Management Company Limited | Households | 2024 |
| 123 Brondesbury Road Limited | Households | 2019 |
| 123 Buckingham Palace Road Tenant Limited | Real estate | 2018 |
| 123 Business Accounting Limited | Professional & scientific | 2018 |
| 123 Cannon Street Limited | Real estate | 2023 |
| 123 Care Ltd | Health & social care | 2019 |
| 123 Clarendon Road Limited | Real estate | 2015 |
| 123 Cleaners Limited | Real estate | 1996 |
| 123 Cleaners London Ltd | Other services | 2022 |
| 123 Click Limited | Information & communication | 2023 |
| 123 Coldershaw Road Freehold Ltd | Real estate | 2016 |
| 123 Company Formations Ltd | Information & communication | 2020 |
| 123 Company Services Ltd | Other services | 2025 |
| 123 Court Hill Road Lewisham Limited | Households | 2004 |
| 123 Done Ltd | Other services | 2025 |
| 123 Drakefell Road Limited | Real estate | 2008 |
| 123 FIX Ltd | Administrative & support | 2026 |
| 123 Gloucester Avenue (Management) Limited | Real estate | 2015 |
| 123 Gloucester Terrace London W 2 Limited | Real estate | 2001 |
| 123 Golden Lane Ltd | Real estate | 2023 |
| 123 Graham Road Limited | Households | 2006 |
| 123 Holding Group Ltd | Administrative & support | 2025 |
| 123 Hvac Ltd | Construction | 2026 |
| 123 Ideas Limited | Construction | 2024 |
| 123 Ifield Road SW10 Limited | Households | 2013 |
| 123 Inc Ltd | Other services | 2026 |
| 123 Isledon Road Flat Management Limited | Real estate | 2001 |
| 123 Itworks Ltd | Information & communication | 2015 |
| 123 Kensington Estates Ltd | Real estate | 2023 |
| 123 Kilburn Lane Management Company Limited | Hospitality | 2007 |
| 123 King Henry's Road Ltd | Households | 1998 |
| 123 Kneller Limited | Real estate | 2021 |
| 123 Leander Road Limited | Households | 2016 |
| 123 Leyton Rental Limited | Real estate | 2023 |
| 123 Lighting Ltd | Administrative & support | 2011 |
| 123 Limited | Extraterritorial | 2019 |
| 123 Media Group Limited | Information & communication | 2025 |
| 123 Motor Group Ltd | Wholesale & retail | 2025 |
| 123 Poppleton Road Limited | Other services | 2017 |
| 123 Prime Meridian Ltd | Real estate | 2024 |
| 123 Properties Ltd | Real estate | 2017 |
| 123 Randolph AVE (Freehold) Ltd | Households | 2018 |
| 123 Real Estates Ltd | Real estate | 2024 |
| 123 Repair Ltd | Other services | 2022 |
| 123 Shakspeare Walk Management Company Limited | Households | 2017 |
| 123 Shenley Road Limited | Households | 2025 |
| 123 Signed Ltd | Information & communication | 2018 |
| 123 Sinclair Road Limited | Households | 2018 |
| 123 Site Solutions Ltd | Construction | 2024 |
| 123 Smartkids Limited | Wholesale & retail | 2003 |
| 123 Southgate Road Limited | Households | 1995 |
| 123 ST Georges Drive Management Company Limited | Households | 1999 |
| 123 ST Johns Way Management Company Limited | Extraterritorial | 2005 |
| 123 Stem Limited | Education | 2023 |
| 123 Surveyors Ltd | Construction | 2021 |
| 123 Sutherland Avenue Limited | Households | 2011 |
| 123 Technology Limited | Information & communication | 2004 |
| 123 Trading Ltd. | Wholesale & retail | 2021 |
| 123 Victoria Way Residents Limited | Households | 2001 |
| 123 Water Gardens Limited | Construction | 2021 |
| 123 WBR Limited | Households | 2022 |
| 123 West END Lane Limited | Real estate | 2025 |
| 123&ABC Limited | Information & communication | 2022 |
| 123, Canfield Gardens Limited | Households | 1976 |
| 123-125 Gloucester Place RTM Company Limited | Real estate | 2018 |
| 123-125 Harley Street RTM Company Limited | Households | 2023 |
| 123-125 Merton Road Development Limited | Construction | 2019 |
| 123-SHINE Holiday Camp Ltd | Health & social care | 2024 |
| 123/124 Lower Marsh Management Limited | Real estate | 2000 |
| 1234 Mission Ltd | Information & communication | 2026 |
| 12345 Retail Group Limited | Wholesale & retail | 2022 |
| 12345.TECH Limited | Other services | 2016 |
| 1234567 Limited | Extraterritorial | 2008 |
| 123456789 Ltd | Professional & scientific | 2025 |
| 12391820 Limited | Other services | 2020 |
| 123A Clarendon Limited | Hospitality | 2025 |
| 123A Clarendon Road Trading Limited | Hospitality | 2024 |