| 30 and 30A Cavendish Avenue RTM Company Ltd | Households | 2017 |
| 30 and 31 Compton Road Freehold Company Limited | Households | 2011 |
| 30 and 32 Kenley Road Freehold Limited | Households | 2025 |
| 30 Aspinall Road Freehold Limited | Households | 2006 |
| 30 Aubert Park Management Limited | Households | 2001 |
| 30 Avonmore Road Limited | Households | 1987 |
| 30 Aynhoe Road Freehold Limited | Households | 2017 |
| 30 Balls Pond Road RTM Company Limited | Households | 2023 |
| 30 Barrels Ltd | Professional & scientific | 2021 |
| 30 Bassein Park Road (Management Company) Limited | Real estate | 2002 |
| 30 Belsize Square Management Company Limited | Households | 2013 |
| 30 Birnam Road Management Co. Limited | Households | 2008 |
| 30 Blythwood Road Limited | Households | 2011 |
| 30 Bolingbroke Road Limited | Households | 2002 |
| 30 Bramber Road Limited | Real estate | 2015 |
| 30 Brandram Road Management Company Limited | Households | 1996 |
| 30 Bruton Street Retail Ltd | Wholesale & retail | 2017 |
| 30 Campden Hill Gardens Limited | Households | 2014 |
| 30 Cannon Street Limited Partnership | | 2006 |
| 30 Carlingford Road Limited | Professional & scientific | 1978 |
| 30 Cato Street Limited | Households | 2022 |
| 30 Ceylon Road RTM Company Limited | Households | 2024 |
| 30 Churchill Place Tenant Limited | Real estate | 2019 |
| 30 Churchill Road & Co. Ltd. | Extraterritorial | 2006 |
| 30 Clarendon Road Limited | Administrative & support | 2018 |
| 30 Clarges Street Limited | Households | 1983 |
| 30 Clicks Ltd | Professional & scientific | 2025 |
| 30 Collingham Place Management Limited | Real estate | 2007 |
| 30 Commerce Road Limited | Real estate | 2020 |
| 30 Comyn Road Management Company Limited | Real estate | 2006 |
| 30 Cotham Road Limited | Households | 1984 |
| 30 Courtfield Gardens Management Company Limited | Real estate | 2014 |
| 30 Creffield Road (Management) Limited | Households | 2001 |
| 30 Cromwell Grove RTM Company Limited | Households | 2023 |
| 30 Crookham Road Ltd | Households | 2020 |
| 30 Crooms Hill Management Company Limited | Households | 1995 |
| 30 Daleham Gardens Limited | Real estate | 1998 |
| 30 Day Architecture Limited | Professional & scientific | 2024 |
| 30 Day Extensions Kingston Ltd | Construction | 2024 |
| 30 Day Extensions Wimbledon Ltd | Construction | 2024 |
| 30 DE Vere Gardens Freehold Company Limited | Real estate | 2016 |
| 30 Dean Street Ltd | Hospitality | 2024 |
| 30 Decades Ltd | Information & communication | 2022 |
| 30 Degree Capital Ltd | Financial services | 2022 |
| 30 Degrees North Ltd | Professional & scientific | 2013 |
| 30 Dornton Road Limited | Real estate | 2024 |
| 30 Duncan Terrace Limited | Households | 1983 |
| 30 East Tenter Street Management Limited | Real estate | 2008 |
| 30 Eccleston Road Management Limited | Households | 2024 |
| 30 Eccleston Square Limited | Real estate | 2002 |
| 30 Edbrooke Road Limited | Households | 2006 |
| 30 Elder Avenue Ltd | Households | 2007 |
| 30 Elmbourne Road (Freehold) Limited | Households | 2000 |
| 30 Elthorne Avenue Ltd | Households | 2020 |
| 30 Ennismore Gardens (Headlease) Ltd | Households | 2006 |
| 30 Exeter Road RTM Company Limited | Households | 2023 |
| 30 Fairhazel Gardens Management Limited | Households | 1993 |
| 30 Fairlop Road Limited | Households | 2001 |
| 30 Ferndale Avenue RTM Company Limited | Households | 2021 |
| 30 Ferndale Road (2008) Limited | Real estate | 2008 |
| 30 Fernlea Road Management Company Limited | Households | 1994 |
| 30 Fernshaw Road, London SW10 Limited | Households | 1986 |
| 30 Fontenoy Road Management Limited | Households | 1998 |
| 30 Forest Hill Limited | Real estate | 2020 |
| 30 Friern Road Freehold Ltd | Households | 2015 |
| 30 Frognal Lane Freehold Limited | Households | 2023 |
| 30 Frognal Limited | Real estate | 2007 |
| 30 Gauden Road Limited | Real estate | 2014 |
| 30 Glazbury Road Freehold Limited | Households | 2014 |
| 30 Glebe Road Ltd | Financial services | 2016 |
| 30 Gledstanes Road Limited | Households | 1998 |
| 30 Gleneagle Road Management Limited | Households | 1994 |
| 30 Glenhurst Freehold Limited | Households | 2020 |
| 30 Gloucester Crescent RTM Company Limited | Households | 2013 |
| 30 Gloucester Terrace RTM Company Limited | Households | 2009 |
| 30 Gordon Place Freehold Limited | Real estate | 2010 |
| 30 Goring Ltd | Real estate | 2020 |
| 30 Grays Inn Limited | Administrative & support | 2014 |
| 30 Greenside Road Freehold Limited | Extraterritorial | 2008 |
| 30 Grosvenor Restaurant Limited | Financial services | 2023 |
| 30 Grosvenor Restaurant Opco Limited | Hospitality | 2024 |
| 30 Grosvenor Restaurant Propco Ltd | Real estate | 2023 |
| 30 Gruneisen Road Limited | Real estate | 2002 |
| 30 GS GP LLP | | 2018 |
| 30 GS LP | | 2018 |
| 30 GS Management Services Limited | Administrative & support | 2023 |
| 30 GS Nominee 1 Limited | Real estate | 2018 |
| 30 GS Nominee 2 Limited | Real estate | 2018 |
| 30 Gunter Grove Limited | Households | 2018 |
| 30 Gunterstone Road Management Limited | Financial services | 2013 |
| 30 Harcourt Terrace Limited | Households | 1997 |
| 30 Hemberton Road Limited | Households | 1987 |
| 30 Hemstal Road Management Company Limited | Households | 1994 |
| 30 Highview Road Management Limited | Households | 1982 |
| 30 Holly Grove Limited | Households | 2002 |
| 30 Hornton ST Freehold Limited | Households | 2015 |
| 30 Howard Road Limited | Households | 1979 |
| 30 Hyde Park Square (London) Limited | Households | 1996 |
| 30 Ickburgh Road RTM Company Limited | Households | 2022 |
| 30 Kemplay Road Freehold Limited | Households | 2018 |