| Company | Timeline | Status | |
| WJ Management Limited Director • Civil Engineer | 14 Jul 1997←11 Years→1 Nov 2008 | Active | |
WJ Associates Limited Director • Civil Engineer | 17 Sep 1992←16 Years→1 Nov 2008 | Dissolved | |
| WJ Groundwater Limited Director • Civil Engineer | 13 Mar 1992←16 Years→1 Nov 2008 | Active | |
| Environmental Geotechnics Limited Director • Civil Engineer | 28 Jan 1991←4 Years→18 Dec 1995 | Liquidation | |
