30 St Mary Axe nearly oblivious to the tower's existence until directly underneath it. The building was constructed by Skanska, completed in December 2003 and opened on 28 April 2004. The primary occupant of the building is Swiss Re, a global reinsurance company, which had the building commissioned as the head office for its UK operation. The tower is thus sometimes known as the Swiss Re Building, although this name has never been official and has more recently fallen out of favour, since the company's main headquarters is in Zurich and the Gherkin name has become more popular. The building uses energy-saving methods which
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,