| Name | Company Number | Date Appointed | Rating |
|---|---|---|---|
| Docklands Railway International Ltd | 03304478 | 19/12/1997 | Dissolved |
| Serco Health Fm Ltd | 03393858 | 03/02/1998 | Dissolved |
| Name | Company Number | Date Appointed | Date Resigned | Rating |
|---|---|---|---|---|
| Cambridgeshire Custodial Services Ltd | 03931288 | 12/04/2000 | 20/03/2003 | Dissolved |
| Club Athletica (Worcester) Ltd | 02152388 | 28/08/1997 | 19/05/2000 | Dissolved |
| Club Athletica Ltd | 02834869 | 01/10/1996 | 19/05/2000 | Dissolved |
| Community Leisure Management Ltd | 02163239 | 29/01/1998 | 19/05/2000 | Dissolved |
| IPSWICH TOWN FINANCE COMPANY LIMITED | 04207245 | 26/09/2003 | 03/10/2008 | Dissolved |
| IPSWICH TOWN FOOTBALL CLUB COMPANY LIMITED | 00315421 | 26/09/2003 | 31/12/2008 | Amber |
| IPSWICH TOWN PLC | 04792070 | 26/09/2003 | 31/12/2008 | Bronze |
| IPSWICH TOWN PROPERTY COMPANY LIMITED | 04387034 | 26/09/2003 | 03/10/2008 | Not Trading |
| IPSWICH TOWN STADIUM COMPANY LIMITED | 04170530 | 26/09/2003 | 03/10/2008 | Not Trading |
| Itnet Ltd | 03036256 | 03/02/2005 | 07/03/2005 | Dissolved |
| KILMARNOCK PRISON SERVICES LIMITED | 03226951 | 30/04/1999 | 20/03/2003 | Amber |
| London Call Centre Co Ltd | 03334238 | 29/01/1998 | 19/05/2000 | Dissolved |
| NPL MANAGEMENT LIMITED | 02937881 | 22/09/1999 | 17/04/2003 | Gold |
| PREMIER CUSTODIAL FINANCE LIMITED | 03849244 | 01/12/1999 | 20/03/2003 | Amber |
| PREMIER CUSTODIAL INVESTMENTS LIMITED | 03849142 | 01/12/1999 | 20/03/2003 | Bronze |
| PREMIER PRISON SERVICES LIMITED | 02733334 | 15/07/1999 | 20/03/2003 | Dissolved |
| Premier Custodial Group Ltd | 03849249 | 01/12/1999 | 20/03/2003 | Dissolved |
| Premier Detention Services Ltd | 03931282 | 12/04/2000 | 20/03/2003 | Dissolved |
| Premier Monitoring Services Ltd | 03522756 | 15/07/1999 | 20/03/2003 | Dissolved |
| Premier Training Services Ltd | 03488626 | 15/07/1999 | 20/03/2003 | Dissolved |
| Prime Contractors Ltd | 02378246 | 29/01/1998 | 19/05/2000 | Dissolved |
| SERCO DOCKLANDS LIMITED | 03145194 | 07/03/1997 | 30/06/1999 | Dissolved |
| SERCO EUROPE LIMITED | 00451392 | 29/01/1998 | 31/01/2000 | Dissolved |
| SERCO GEOGRAFIX LIMITED | 03522659 | 15/07/1999 | 20/03/2003 | Dissolved |
| SERCO GROUP PLC | 02048608 | 01/12/1995 | 19/06/1996 | Silver |
| SERCO GROUP PLC | 02048608 | 29/02/1996 | 11/05/2010 | Silver |
| SERCO INTERNATIONAL LIMITED | 02324094 | 29/01/1998 | 02/11/2000 | Silver |
| SERCO INVESTMENTS LIMITED | 03287461 | 28/11/1996 | 04/02/2000 | Dissolved |
| SERCO LIMITED | 00242246 | 29/01/1998 | 26/04/2001 | Silver |
| SERCO-IAL LIMITED | 00427272 | 29/01/1998 | 24/03/2000 | Silver |
| Salco Ltd | SC119531 | 29/01/1998 | 19/05/2000 | Dissolved |
| Serco Inactive 1 Ltd | 02269522 | 29/01/1998 | 31/01/2000 | Dissolved |
| Serco International Services Ltd | 02568815 | 06/01/1997 | 18/05/2000 | Dissolved |
| Serco Leisure Ltd | 02202587 | 29/01/1998 | 19/05/2000 | Dissolved |
| Serco Maintenance Services Ltd | 02674902 | 29/01/1998 | 16/05/2001 | Dissolved |
| Serco Management Ltd | 02107698 | 31/12/1996 | 09/06/1999 | Dissolved |
| Serco Management Services Ltd | SC148516 | 29/01/1998 | 19/05/2000 | Dissolved |
| Serco Nomura Infrastructure Management Ltd | 03707625 | 29/01/1999 | 08/11/2000 | Dissolved |
| Serco Project Development Ltd | 02834872 | 25/11/1996 | 19/05/2000 | Dissolved |
| Serco Railtest Ltd | 03114741 | 29/01/1998 | 15/09/1998 | Dissolved |
| Serco Services Ltd | SC145051 | 29/01/1998 | 01/04/2000 | Dissolved |
| Serco Systems Ltd | 01861237 | 05/02/1998 | 12/11/2002 | Dissolved |
| Sercoserve Ltd | 02497013 | 29/01/1998 | 19/05/2000 | Dissolved |