| 30 Keswick Road Owners Company Limited | Hospitality | 2001 |
| 30 Kings Avenue Management Company Limited | Households | 1986 |
| 30 Kings Road Property Management Limited | Households | 2011 |
| 30 Kirkdale Management Company Limited | Households | 2006 |
| 30 Kyverdale Road Limited | Households | 2013 |
| 30 Lancaster Road (SE25) Freehold Management Limited | Households | 2014 |
| 30 Langham Street Limited | Real estate | 2016 |
| 30 Lanhill Road RTM Company Limited | Hospitality | 2015 |
| 30 Linden Gardens Management Company Limited | Households | 2009 |
| 30 Linden Grove RTM Company Limited | Hospitality | 2009 |
| 30 Lower Addison Gardens Limited | Households | 1996 |
| 30 Lupus Street Freehold Limited | Households | 2019 |
| 30 Malbrook Road Residents' Association Limited | Real estate | 1989 |
| 30 Manor Park Freehold Limited | Households | 2013 |
| 30 Marlborough Road Limited | Households | 2022 |
| 30 Marler Road (Freehold) Limited | Hospitality | 2004 |
| 30 Marmora Road RTM Company Limited | Real estate | 2020 |
| 30 Marylands Limited | Households | 2014 |
| 30 Minories Hub Investorco Limited | Financial services | 2025 |
| 30 Nevern Place Freehold Limited | Households | 2007 |
| 30 Newton Road Ltd | Households | 2020 |
| 30 NIX Ltd | Arts & recreation | 2021 |
| 30 Northampton Square Management Company Ltd | Households | 2022 |
| 30 Oakley Street Limited | Households | 1995 |
| 30 Old Street (London) Management Company Limited | Households | 2025 |
| 30 Palace Court Management Limited | Professional & scientific | 1995 |
| 30 Palewell Park Limited | Households | 1997 |
| 30 Park Avenue RTM Company Limited | Households | 2019 |
| 30 Park Hall Road Limited | Real estate | 2001 |
| 30 Park Street Limited | Real estate | 2012 |
| 30 Pembridge Crescent Limited | Construction | 2025 |
| 30 Percent Club IP Co. Limited | Financial services | 2022 |
| 30 Pont Street Limited | Real estate | 2023 |
| 30 Portland Rise N4 Freehold Limited | Households | 2023 |
| 30 Princes Avenue Limited | Real estate | 2008 |
| 30 Putney Bridge Road Ltd | Real estate | 2011 |
| 30 RCG Limited | Construction | 2015 |
| 30 Rita Road (Freehold) Limited | Extraterritorial | 2007 |
| 30 Robson Avenue Limited | Real estate | 2017 |
| 30 Rosemont Ltd | Households | 2023 |
| 30 Rosenthal Road RTM Company Limited | Households | 2018 |
| 30 Rowfant Road Limited | Extraterritorial | 2009 |
| 30 Rundell Crescent (Hendon) Management Limited | Real estate | 1986 |
| 30 Rusholme Road Ltd | Households | 1999 |
| 30 Seconds Ltd | Hospitality | 2025 |
| 30 Shenley Road Freehold Company Ltd | Households | 2023 |
| 30 Shieldhall Limited | Real estate | 2025 |
| 30 Sisters Avenue Limited | Households | 2023 |
| 30 Sloane Garden Freehold Limited | Households | 2007 |
| 30 Something Fertility Ltd | Health & social care | 2026 |
| 30 South Hill Park London Limited | Extraterritorial | 2012 |
| 30 South Villas Limited | Households | 2008 |
| 30 Spenser Road Limited | Extraterritorial | 1997 |
| 30 Stanhope Road Highgate Residents Association Limited | Households | 1999 |
| 30 Stanmore Road Limited | Households | 2017 |
| 30 Station Road LP | | 2019 |
| 30 Station Road Nominee 1 Limited | Extraterritorial | 2019 |
| 30 Station Road Nominee 2 Limited | Extraterritorial | 2019 |
| 30 Steps Ltd | Financial services | 2025 |
| 30 Stowe Road (Freehold) Limited | Households | 2003 |
| 30 Sydney Road Limited | Households | 2017 |
| 30 Technology Limited | Financial services | 2022 |
| 30 Tetherdown Limited | Households | 1988 |
| 30 Thames Road Management Company Limited | Households | 1996 |
| 30 Thornton Hill Management Limited | Households | 2009 |
| 30 Tite Street Management Company Limited | Households | 2022 |
| 30 Upper Park Road Property Management Limited | Households | 2019 |
| 30 Warwick Street LP | | 2015 |
| 30 Wellesley Road Management Limited | Real estate | 2019 |
| 30 Wellmeadow Road (London) Limited | Households | 2017 |
| 30 Wessex Gardens Limited | Real estate | 2020 |
| 30 WHL Freehold Limited | Households | 2026 |
| 30 Willoughby Road Limited | Administrative & support | 1995 |
| 30 Winchester Road Limited | Households | 1995 |
| 30 Winchester Street Freehold Company Limited | Households | 2024 |
| 30 Woodstock Grove Management Company Limited | Real estate | 1992 |
| 30, 30A and 32 POW Drive (Freehold) Ltd | Real estate | 2021 |
| 30, Brondesbury Villas Limited | Households | 1978 |
| 30,000 Days Limited | Professional & scientific | 2019 |
| 30-31 Golden Square GP LLP | | 2024 |
| 30-31 Golden Square LP | | 2015 |
| 30-31 Golden Square Nominee 1 Limited | Extraterritorial | 2015 |
| 30-31 Golden Square Nominee 2 Limited | Extraterritorial | 2015 |
| 30-32 Cross Street Management Company Limited | Real estate | 2002 |
| 30-32 Friern Park Management Company Limited | Real estate | 2008 |
| 30-32 Seven Sisters Road RTM Company Limited | Households | 2025 |
| 30-33 Denton ST Limited | Real estate | 2013 |
| 30/30A Byegrove Road Limited | Households | 2017 |
| 30/30A Cumberland Road Limited | Real estate | 1997 |
| 30/31 Cleveland Square Limited | Households | 1997 |
| 30/32 Alexandra Gardens Management Company Limited | Real estate | 2012 |
| 30/32 Heysham Road (Freehold) Limited | Households | 2021 |
| 300 Abbey Ltd | Real estate | 2025 |
| 300 Abbey SUB Ltd | Real estate | 2025 |
| 300 Coldharbour Lane (Residents) Company Limited | Real estate | 2001 |
| 300 Guards Limited | Administrative & support | 2021 |
| 300 Queens Road RTM Company Ltd | Households | 2016 |
| 300 Recycling Ltd | Other services | 2025 |
| 300 Security Services Ltd | Wholesale & retail | 2022 |
| 300 Stepney Way (Freehold) Limited | Households | 2024 |