Trinity Hill, a mid-sized Hawkes Bay wine producer, said US winery owner Charles Banks planned to take a controlling 67 per cent stake in the company, subject to regulatory approvals.
The purchase price was not disclosed.
Charles Banks, through his company Terroir Selections, already has a 24.9 per cent stake in Trinity Hill - another medium-sized winery producing around 60,000 cases of wine a year.
Trinity Hill chief executive Michael Henley said Trinity Hill founders Robyn Wilson and John Hancock intended to remain as shareholders in the company, which is a prominent producer in Hawkes Bay.
The company is Charles Banks's first wine investment in New Zealand. His other wine holdings are in the United States and South Africa.
Through Terroir Selections, Banks owns and distributes some of California's highest profile wineries including Mayacamas, California's oldest cabernet producer. He also owns leading South African winery Mulderbosch.
"Trinity Hill is in a terrific position to prosper having consistently delivered high quality wines across its range," Banks said in a statement.
"We intend to invest the necessary capital to allow the continued improvement in quality," he said.
Trinity Hill's chairman and co-founder Robyn Wilson said the acquisition meant the company would be able to get its flagship wines the Homage and The Gimblett on to US wine lists.
Wilson, a London-based New Zealander who owns London's Bleeding Heart Restaurant Group, said Banks's move would allow Trinity Hill to develop in more areas.
Trinity Hill was established in 1993 and had its first vintage in 1997.