The €5.4 billion (£4.5bn, $7.4bn) sale of Nokia's Devices and Services division to Microsoft has been put back until next month, both firms have announced.
When the deal was first announced in September, it was stated that the deal would close during the first quarter of 2014.
The delay in the transaction comes as a result of approvals still pending from antitrust authorities in Asia, following approvals already received from the European Commission and the US Department of Justice.
"We are nearing the final stages of our global regulatory approval process," Brad Smith, Microsoft's general counsel, wrote on the company's website. "To date we have received approvals from regulatory authorities in 15 markets on five continents. Currently, we are awaiting approval confirmation in the final markets. This work has been progressing, and we expect to close next month, in April 2014."
Nokia reiterated these reasons in its own statement released shortly after, claiming: "Nokia and Microsoft continue to make good progress related to the closing conditions and integration planning."
The Finnish firm stated that its ongoing tax proceedings in India had no bearing on the timing of the deal closing.
Earlier this month, India's Supreme Court refused to hear an appeal from Nokia relating to an earlier ruling concerning the transfer of one of its biggest handset factories in Chennai to Microsoft.
Other high-profile acquisitions by the California-based company have taken similarly long periods of time to complete. In 2011, Microsoft took five months to complete its takeover of online chat company Skype.