 Also, following the death of the tower's architect Harry Seidler on 9 March 2006, a powerful light was temporarily installed on the roof of QV1 to shine a beam into the sky as a memorial.The BTA Property Trust sold its half-stake in the building in 1998 to corporate stablemate BT Office Trust for $130.6 million.In 2003 that half-stake was acquired by Investa Property Group, which in 2006 valued QV1 at $400 million.