The judging panel praised the vast office project, which had an estimated budget of £1 billion, for its commitment to sustainability and the architect and client's determination to be a "good neighbour" with the City of London.
"By building at a lower height than approved at planning, reserving parts of the site for public space, and using highly-detailed, handcrafted materials, Bloomberg shows a high level of generosity towards the City," said the judges. "This is a building of its place."
Described by RIBA president Ben Derbyshire as a "monumental achievement", the project is thought to be the largest stone building built in the area since St Paul's Cathedral was erected in the 17th century.
"The real success though," continued the jury, "is in the experience for staff, visitors or passers-by – how Bloomberg has opened up new spaces to sit and breathe in the City; the visceral impact of the roof-top view across to St Paul’s from the concourse space, the energy of descending the helix ramp or settling into a desk in one of the dynamic new workspaces."
Bloomberg HQ claims to be the most sustainable office building in the world, and was given a 98.5 per cent score by BREEAM. It was designed to use 73 per cent less water and 35 per cent less energy than a standard office building.
Bronze fins on the Derbyshire sandstone facade can open and close for natural ventilation, and bespoke ceiling panels in the shape of petals combine energy-saving LED lights with heating, cooling and acoustic functions.