| Recommended Freight Limited | Transport & logistics | 2006 |
| Recon Airsoft Supplies Ltd | Wholesale & retail | 2018 |
| Red Castle Homes Limited | Professional & scientific | 1985 |
| Redack Holdings Limited | Financial services | 2023 |
| Redhead & Brown Limited | Wholesale & retail | 1939 |
| Redman Design Ltd | Professional & scientific | 2000 |
| Regional Collection Services Limited | Administrative & support | 1992 |
| Renaissance Point Management Limited | Households | 2002 |
| Rent-A-Writer Ltd | Professional & scientific | 2000 |
| Residents of Collingwood Limited | Households | 1997 |
| Revolution Digital Marketing UK Limited | Administrative & support | 2021 |
| Rite-Vent Holdings Limited | Professional & scientific | 1996 |
| Rite-Vent Limited | Manufacturing | 1968 |
| Rivermeade Signs Limited | Manufacturing | 1997 |
| Robsons Boat Builders Limited | Energy | 1964 |
| Rockcliff Rugby Ground Limited | Arts & recreation | 1950 |
| Rodney Court (Whitley Bay) Management Company Limited | Households | 1996 |
| Roflow Limited | Manufacturing | 1990 |
| Rokeford Ltd | Financial services | 2023 |
| Romano's Limited | Hospitality | 1999 |
| RON Joyce Limited | Professional & scientific | 2002 |
| Rosenthal & Co. Limited | Professional & scientific | 1988 |
| RVA Investments Limited | Financial services | 2022 |
| Ryhope Catholic Club | Hospitality | 2007 |
| S and B EPS Holdings Limited | Financial services | 2023 |
| S and B EPS Property Limited | Real estate | 2023 |
| S Mason Legal Services Ltd | Professional & scientific | 2006 |
| S.R. Transport Services Limited | Transport & logistics | 2001 |
| Sadler Joyce Limited | Professional & scientific | 1998 |
| Safc.Com PLC | Arts & recreation | 2000 |
| Safety Advisory Consultants Ltd | Administrative & support | 2009 |
| Sang Properties Limited | Real estate | 2006 |
| Sapphire Security Systems Limited | Administrative & support | 1993 |
| Sarah Spruce Limited | Professional & scientific | 2024 |
| Schiedel Chimney Systems Limited | Professional & scientific | 2004 |
| Schiedel Rite-Vent Limited | Professional & scientific | 2003 |
| Scotsbank Motor Services Ltd | Wholesale & retail | 2003 |
| Scrapper Reed Productions Ltd | Information & communication | 2004 |
| SDL Management Services Limited | Professional & scientific | 2002 |
| Seaton Hospitality Limited | Hospitality | 2023 |
| Seaweed Solutions Limited | Information & communication | 1997 |
| Selling Situations Limited | Administrative & support | 2006 |
| Senier Consulting Ltd | Education | 2006 |
| Servace Limited | Manufacturing | 1999 |
| Shiney Stores Ltd | Wholesale & retail | 2025 |
| Silentherm(Commercial Heating)Co.Limited | Wholesale & retail | 1972 |
| SJT Concierge and Lifestyle International Limited | Administrative & support | 2024 |
| Skelton Healthcare Ltd | Wholesale & retail | 2025 |
| Slaters Electricals Holdings Limited | Financial services | 2016 |
| Smartgo Limited | Information & communication | 2000 |
| Smith Barbering Co. Ltd | Other services | 2008 |
| South Northumberland Cricket Club Limited | Arts & recreation | 1927 |
| South Shields Specsavers Limited | Wholesale & retail | 1992 |
| Southern Green Limited | Professional & scientific | 2002 |
| Spacechange Residents Management Limited | Households | 1988 |
| Spectrum Builders Ltd | Real estate | 2007 |
| Springfield Properties (Ncle) Limited | Real estate | 1997 |
| Springwell Building Developments LLP | | 2025 |
| Springwell Construction Limited | Construction | 2025 |
| ST Martins Court (Whitley Bay) Management Company Limited | Households | 1998 |
| St.Andrews Court Management (Tynemouth) Limited | Households | 1972 |
| Stellar Services Ltd | Transport & logistics | 2026 |
| Stelrad Management Limited | Professional & scientific | 2000 |
| Stelrad Radiator Holdings Limited | Professional & scientific | 2000 |
| Stephenson Electrical Services (North East) Limited | Wholesale & retail | 1998 |
| Stephenson Gobin Limited | Manufacturing | 1972 |
| Steven Hiscock & Partners | | 1992 |
| Stevenson Scott Limited | Transport & logistics | 2000 |
| Stevol Associates Limited | Real estate | 2003 |
| Stonebanks Properties Limited | Real estate | 2017 |
| Sun Care Maintenance Ltd | Manufacturing | 2009 |
| Sunderland Basketball Club Limited | | 1976 |
| Sunderland MOT Centre Limited | Wholesale & retail | 2007 |
| Sunderland Scuba Centre Ltd | Arts & recreation | 2006 |
| Sunderland Women's Centre | Education | 2004 |
| Sunny Jewellers Ltd | Wholesale & retail | 2006 |
| Supplyfast Limited | Real estate | 1999 |
| Swift Brake & Clutch Limited | Wholesale & retail | 1999 |
| Systematic Shop Fitting Limited | Construction | 1994 |
| T. Tote Transport Ltd | Construction | 2002 |
| T.M.H. Groundworks Limited | Construction | 2004 |
| Tandembeck Limited | Manufacturing | 2000 |
| TAU Properties Limited | Hospitality | 2002 |
| Tax Shop Direct Limited | Professional & scientific | 1997 |
| Team Holdings Ltd | Real estate | 2024 |
| Tecnospec Ltd | Professional & scientific | 2006 |
| Teesdale Paving Limited | | 1983 |
| Terra Infirma Ltd | Other services | 2007 |
| Terrys Hairdressing (TCB) Limited | Other services | 2007 |
| TGB Company Services Limited | Professional & scientific | 2003 |
| THE Archaeological Practice Limited | Professional & scientific | 2002 |
| THE Bunker (Sunderland) Community Interest Company | Arts & recreation | 2002 |
| THE Cheviot Bellingham Ltd | Hospitality | 2024 |
| THE Chiropody Clinic Limited | Health & social care | 2006 |
| THE Customs House Green Room Limited | Hospitality | 2006 |
| THE Cutting Court Ltd | Other services | 2003 |
| THE Deli Around the Corner Limited | Wholesale & retail | 2005 |
| THE GAS Trade Centre Limited | Construction | 2003 |
| THE Grasmere Boat Company Ltd | Arts & recreation | 2005 |
| THE Heat Machine Company Limited | Wholesale & retail | 1982 |