The Insight deal is subject to the approval of a majority of the outstanding shares of Diligent common stock and preference shares, voting as one class; the approval of least 60 per cent of the outstanding Diligent preference shares, voting separately; regulatory approvals and other customary closing conditions, including that the existing directors will resign on closing, the company said.
The holders of Diligent's preference shares, including Spring Street Partners, Diligent's largest shareholder, have entered voting agreements in support of the deal.
A special shareholders' meeting will be scheduled "as soon as practicable".
The deal is expected to close in the second quarter of this year, at which point Diligent would be de-listed from the NZX.
Diligent chief executive Brian Stafford said it was an "exciting day" for the company.
"I'm thrilled to partner with Insight, which brings substantial experience supporting the growth of software companies around the world," he said. "Our game plan will not change as a private company - to be the leading provider of collaboration software for boards, committees, and leadership teams."
Stafford said Diligent's current senior management team would continue to run the business after the deal closed.
New York-based Insight is best known for making investments in start-ups and growth-stage firms, but has also participated in corporate takeovers before, according to Reuters.
Insight managing director Deven Parekh said his firm was looking forward to working with Diligent to "accelerate the company's progress in the large and growing communications and collaboration market".
"Diligent leads the way in collaboration between boards and senior executives withmore than 3,500 clients,tremendous innovation and unparalleled service," Parekh said.
