The US Department of Justice has given the go-ahead for Microsoft to take over Nokia's mobile devices and services business, according to a notification from the Federal Trade Commission's Bureau of Competition.
The €5.4 billion (£4.6 billion) acquisition was first announced in September, with the final transaction expected to be completed in the first quarter of 2014. Before then the deal still needs to get approval from the European Union, who will decide if it breaches EU competition rules. However, it is expected that the regulators will approve the deal without any conditions.
"We look forward to the date when our partners at Nokia will become members of the Microsoft family, and are pleased that the Department of Justice has cleared the deal unconditionally," a Microsoft spokesperson said in a statement.
The deal will see Nokia CEO Stephen Elop return to his former company as vice president of the newly created Nokia division, in charge of 32,000 Nokia executives and employees who are also making the move to Microsoft.
In a statement released at the time the takeover was announced, Microsoft CEO Steve Ballmer said: "It's a bold step into the future – a win-win for employees, shareholders and consumers of both companies".
When Ballmer revealed his plans to leave Microsoft earlier this year, Elop's name was among those mentioned as a possible successor. However, since then it has been reported that Microsoft has narrowed the search to just two candidates: Ford CEO Alan Mulally and Microsoft Cloud boss Satya Nadella. Microsoft is expected to announce Ballmer's replacement by the end of the year.