| Morgan Power Projects Limited | Professional & scientific | 1975 |
| Motorcool Services Ltd. | Manufacturing | 2001 |
| Mura Asia Limited | Administrative & support | 2024 |
| Mura Grangemouth Limited | Administrative & support | 2026 |
| Mura Monarch Limited | Administrative & support | 2022 |
| Mura North America Limited | Administrative & support | 2021 |
| Mura Technology Limited | Water & waste | 2016 |
| Mura UK Holdings Limited | Administrative & support | 2026 |
| Mura Wilton Limited | Manufacturing | 2016 |
| N K B Associates Limited | Information & communication | 1995 |
| N. V. Q. a. Limited | Professional & scientific | 2001 |
| New Street Business Consulting Limited | Information & communication | 2004 |
| NMM Industrial Limited | Professional & scientific | 2007 |
| North East Toilet Cubicles Limited | Construction | 2006 |
| Northern Machine Tools (Engineering) Holdings Limited | Professional & scientific | 2007 |
| Northern Motor Company (Darlington) Limited | Manufacturing | 1994 |
| O KAY Automatics Limited | Hospitality | 1964 |
| Oak House Commercial Holdings Limited | Hospitality | 2015 |
| Odyssey Systems Limited | Information & communication | 1990 |
| One Three M P Limited | Real estate | 1997 |
| Oscar Fire, Safety & Security Ltd | Other services | 2023 |
| Oxbridge Care Limited | Other services | 2003 |
| P W Industrial Supplies Limited | Wholesale & retail | 2007 |
| P.Mac Associates Limited | Information & communication | 1997 |
| Pactum Solutions Limited | Construction | 2006 |
| Pallian Developments Limited | Real estate | 2006 |
| Pani Limited | Hospitality | 1999 |
| Park Avenue Pharmacy Limited | Wholesale & retail | 1987 |
| Park Gates Leisure Limited | Hospitality | 1986 |
| Park Lane Garages (Teeside) Limited | Wholesale & retail | 2004 |
| Parker Stag Ltd | Real estate | 2006 |
| Partners Properties Limited | Real estate | 2000 |
| Paxton Apparel Ltd | Wholesale & retail | 2026 |
| PD Infrastructure Limited | Construction | 2008 |
| Pembroke Engineering Services Limited | Professional & scientific | 2006 |
| Pennywise Appliances Limited | Wholesale & retail | 2003 |
| Peter Gainey Architectural Services Limited | Professional & scientific | 2006 |
| Pickerings Manufacturing Limited | Manufacturing | 1995 |
| PJH Engineering Services Limited | Other services | 2018 |
| Platform a Limited | Manufacturing | 1999 |
| Pout and Foster Limited | Wholesale & retail | 1975 |
| Precor Limited | | 1982 |
| Press & FAB Limited | Manufacturing | 1992 |
| PSI Developments Limited | Real estate | 2007 |
| Radiation Burn Limited | Information & communication | 2010 |
| Rayment Construction Services Limited | Construction | 2007 |
| Redcar Racecourse Limited | Arts & recreation | 1875 |
| Redpath Offshore (North) Limited | Wholesale & retail | 1945 |
| Redscar OIL & GAS Consultancy Limited | Professional & scientific | 2014 |
| Relyon Digital Limited | Information & communication | 1982 |
| Relyon Nutec UK Limited | Other services | 1993 |
| Renew Wilton Limited | Manufacturing | 2017 |
| Rentor Management Limited | Hospitality | 2001 |
| Ricchel Limited | Wholesale & retail | 2026 |
| Richardson Bros (Haulage) Limited | Administrative & support | 1957 |
| Robert Stevenson Limited | Wholesale & retail | 1955 |
| Robertswood Associates Limited | Households | 2001 |
| Robinsonl Limited | Wholesale & retail | 2025 |
| RON Perry (A19 Test & Tune) Limited | Wholesale & retail | 1989 |
| RS Cranes & Lifting Ltd | Professional & scientific | 2023 |
| RS Industrial Services (North East) Ltd | Professional & scientific | 2022 |
| RS Industrial Supplies Ltd | Professional & scientific | 2023 |
| S & K Power Services Limited | Professional & scientific | 2008 |
| S Currell Plumbing & Heating Ltd | Construction | 2003 |
| S. H. Reily Limited | Health & social care | 1984 |
| Saabat Gallery CIC | Arts & recreation | 2018 |
| Sabic UK Pension Trustees Limited | Professional & scientific | 2006 |
| Saltburn(Lune Street)Social Club,Limited(The) | Hospitality | 1925 |
| Sandersons Removals Limited | Transport & logistics | 1991 |
| Sapphire Internet Limited | Extraterritorial | 1997 |
| Shock the Senses Ltd | Information & communication | 2006 |
| Skidmore Ltd | Extraterritorial | 2023 |
| Skin & Tonic (Teesside) Limited | Other services | 2005 |
| SLS Technical Services Limited | Manufacturing | 2007 |
| Solutions Northern Limited | Financial services | 2004 |
| Sprockets of Guisborough Limited | Wholesale & retail | 2012 |
| ST Anthony's Store Ltd | Wholesale & retail | 2025 |
| Stanley Vickers Limited | Manufacturing | 1956 |
| Steve Lister Developments Limited | Construction | 1992 |
| Stevenson of Oxbridge Limited | Wholesale & retail | 1984 |
| Stockton Decorators Merchants Limited | Wholesale & retail | 2007 |
| Stranton Business Centre Limited | Professional & scientific | 2005 |
| Strickland and Holt Limited | Wholesale & retail | 1941 |
| Stylepark Property Management Limited | Hospitality | 1990 |
| Sutton Arms (Faceby) Limited | Hospitality | 2011 |
| T Malone Ltd | Professional & scientific | 2007 |
| T.P. Skip Hire Limited | Other services | 2001 |
| Taskscene Limited | Professional & scientific | 2001 |
| TDS Safety Limited | Administrative & support | 2024 |
| Technological Vision Ltd | Information & communication | 2022 |
| Techquity Holdings Ltd | Financial services | 2025 |
| Tees & Hartlepool Yacht Club Limited | Arts & recreation | 1997 |
| Tees Components (Holdings) Limited | Extraterritorial | 1998 |
| Tees Components Limited | Manufacturing | 1963 |
| Tees Sailing Club Limited | Arts & recreation | 1964 |
| Teesside Ability Support Centre | Health & social care | 1979 |
| Teesside Environmental Trust | Arts & recreation | 1997 |
| Teesside Project Services Limited | Professional & scientific | 2007 |
| Teesside Properties (2) Limited | Real estate | 1993 |
| Teesside Properties Limited | Real estate | 1993 |