| Company | Timeline | Status | |
| 24 Lewes Crescent Limited Director • Company Director | 21 Feb 2015←10 Years→Current | Active | |
| Koestler (Sales) Limited Director • Director | 10 Dec 2014←3 Years→2 Oct 2018 | Active | |
| H N J Nahapiet Limited Director • Consultant | 7 Feb 2014←9 Years→13 Jun 2023 | Dissolved | |
| Addiewell Prison (Holdings) Ltd Director • Director | 24 Oct 2005←3 Years→26 Feb 2009 | Active | |
| Addiewell Prison Ltd Director • Director | 24 Oct 2005←3 Years→26 Feb 2009 | Active | |
| The Koestler Trust Director • Director | 15 Dec 2004←13 Years→11 Dec 2018 | Active | |
| Peterborough Prison Management Holdings Limited Director • Managing Director | 12 Feb 2003←6 Years→26 Feb 2009 | Active | |
| Peterborough Prison Management Limited Director • Managing Director | 12 Feb 2003←6 Years→26 Feb 2009 | Active | |
| Ashford Prison Services Limited Director • Director | 23 Apr 2002←6 Years→26 Feb 2009 | Active | |
| Ashford Prison Services Holdings Limited Director • Director | 23 Apr 2002←6 Years→26 Feb 2009 | Active | |
