US software giant Microsoft is said to be close to securing unconditional EU antitrust approval for its $16 billion bid for artificial intelligence and speech technology company Nuance Communications. The deal, the latest in the tech industry, comes amid heightened regulatory scrutiny of takeovers by tech giants and acquisitions, where nascent start-ups and potential rivals are shut down. Microsoft announced the deal in April, which will boost its presence in cloud solutions for healthcare customers. The company is believed to be in talks with the UK antitrust agency CMA, ahead of filing a request for approval of the deal. The European Commission, which is scheduled to decide on the deal by December 21, declined to comment. Microsoft also declined to comment. The deal has already received the regulatory green light in the US and Australia. Nuance, known for pioneering speech technology and helping launch Apple's virtual assistant, Siri, serves 77 per cent of US hospitals.