WineBid Inc., said to be the largest online auction house for fine and rare wines, is being acquired by an investment group led by San Francisco-based Third Leaf Partners, which has a portfolio of emerging and established beverage and hospitality brands, the companies said June 8.

The deal still has to be approved by their shareholders, they said. The plan is to keep senior management and staff as well as grow and expand the business.

Napa-based WineBid was started in 1996 and has operations also in Chicago and Hong Kong. WineBid’s CEO called the deal “a great union.”

“The acquisition by Third Leaf's group is a great move for both companies,” said Jerome Zech in the announcement. “Third Leaf’s portfolio of boutique wine and sake brands, and relationships and experience in beverage and hospitality more generally makes them a very complementary partner for WineBid.”

Third Leaf co-founder and managing partner Aaron Faust said he first encountered WineBid a decade ago while buying old and rare wine on the site.

“We were introduced to Jerome and his team in a professional capacity several years ago, and have had a great working relationship,” Faust said. “We’ve been looking for ways to expand and enhance that relationship, and this is the culmination of those efforts. We believe that it will create a strong, strategic alliance for both businesses to create growth opportunities, an excellent return for current shareholders and a dynamic business for WineBid management and staff.”

WineBid said it has 90,000 registered bidders. It claims to have sold so far 684,500 bottles of California cabernet sauvignon wines, 487,900 bottles of Bordeaux, 260,500 of Burgundy, 72,100 bottles of “first growth” labels and 37,300 of Champagne, according to the website (winebid.com).

The company holds 52 auctions a year and said it gets in thousands of bottle weekly.

It also has an import business, Peloton Imports, to offer wines directly from European producers.

Third Leaf is currently working with wineries based in California, Oregon, France and Italy, including Antica Terra, the work of Maggie Harrison, and Gothic Wines, started by Josh Nadel, according to its website (thirdleafpartners.com).