A French insurance company has bought the Calon-Ségur wine estate in Bordeaux for an estimated €170 million ($214 million).

Suravenir, the insurance arm of the Crédit Mutuel Arkéa bank, is the new owner of the 1855 third-growth château and the associated Saint-Estèphe property Capbern Gasqueton.

The local daily newspaper "Sud Ouest" said the purchase of Calon-Ségur marks “the most important transaction in the Bordeaux wine sector this year.” But for its owners, “the sale is heartbreaking,” the paper reported.

The property has been in the Gasqueton family since the 19th century. Hélène Capbern Gasqueton took over in the fall of 2011 after the death of her mother, Denise Capbern Gasqueton, a well-known figure in the Bordeaux wine scene. Despite Hélène's keenness to continue her mother's work, her shareholding nieces wanted the estate sold. Divisions within the family made the sale inevitable, according to "Sud Ouest."

Château Calon-Ségur is a 74-hectare (183-acre) vineyard, according to "The Wines and Domaines of France" by Master of Wine Clive Coates. Plantings are predominantly cabernet sauvignon (which accounts for around 65 percent of vines) merlot and cabernet franc. The winery’s label is distinctive, with a heart surrounding the château’s name.

A spokesman for Crédit Mutuel Arkéa – which has three million clients and 8,700 employees – described the investment as one for the long term. "It diversifies our portfolio and stays true to our business model, which is strongly anchored in our regions.” While this is Suravenir's first investment in a vineyard, a number of leading French insurance companies are well-established winery owners.

In July last year, MACSF acquired Château Lascombes, an 1855 second-growth property in the Margaux appellation, for around €200 million ($252 million).

AXA’s wine arm, AXA Millésimes, also owns Bordeaux properties, including the 1855 second-growth estate Château Pichon Longueville-Baron in the appellation of Pauillac, Château Petit Village in Pomerol and Sauternes first-growth vineyard Château Suduiraut.

Rival insurance firm Crédit Agricole owns a Sauternes first-growth property, Château de Rayne-Vigneau, as well as four châteaux in Bordeaux and properties in the Rhône and Burgundy.