Willis Building (London) 2004 and 2008 under the management of Mace and represented a significant addition to the City of London skyline, becoming its fourth-tallest building after Tower 42, 30 St Mary Axe and CityPoint. The core was topped out in July 2006 and the steelwork completed in September that year. Cladding began in July 2006 and the structure was externally completed by June 2007. It was internally fitted out and officially opened in April 2008. The building was the first in a wave of new tall towers for London's primary financial district. Others included The Pinnacle, the Leadenhall Building and the Heron
30 St Mary Axe for sale with a price tag of £600 million. Potential buyers included British Land, Land Securities, Prudential, ING, and the Abu Dhabi royal family. On 21 February 2007, IVG Immobilien AG and UK investment firm Evans Randall completed their joint purchase of the building for £630 million, making it Britain's most expensive office building. Swiss Re booked a gain of more than £300 million from the sale. The new owners are seeking compensation from four of their former managers on the deal, in which about £620 million was paid for a building with a build cost of about £200 million,