Bill Koch lists storied Cape Cod estate for $23.85M

When billionaire investor, collector and competitive sailor Bill Koch first set foot on Cape Cod in the 1970s, he did so as a guest in one of the area’s most storied estates. 

The summer home of banking heir Paul Mellon and his wife, the renowned horticulturalist Rachel “Bunny” Mellon, was a beacon of quiet elegance, filled with fine art and cultivated gardens — and often visited by close friends Jacqueline and John F. Kennedy.

Now, over a decade after acquiring the estate from Bunny Mellon herself, Koch is ready to part with it, the Wall Street Journal first reported. 

The waterfront compound in Osterville, Massachusetts, a gated enclave of Oyster Harbors, is listed for $23.85 million, one of the priciest properties currently on the market in Cape Cod.

“My main Cape home is next door — it is plenty big for my friends and family now,” Koch said in an email to the Journal. “It is time for someone else to enjoy this marvelous property.”

The roughly 7.5-acre estate, first built in 1954, includes a 7,300-square-foot main house with eight bedrooms, along with two two-bedroom guest cottages, an artist’s studio, a beach house and a greenhouse. 

Winding paths connect the structures across sweeping lawns, with panoramic views of Nantucket Sound. The estate also includes a private dock and more than 500 feet of waterfront.

Listing agents Joanna Dresser and Kelly Crosby of LandVest of Christie’s International Real Estate called the property a rare convergence of provenance and potential. 

“This is a once-in-a-generation opportunity to own a legacy property with both historical provenance and limitless potential,” Dresser told The Post in a statement. “The setting, the history, and the sheer scale of this estate are unmatched on Cape Cod.”

That history runs deep. 

Paul Mellon, whose family established the National Gallery of Art in Washington, D.C., was known for his deep appreciation of fine art and thoroughbred horses. His wife, Bunny, became one of the most influential landscape designers of the 20th century, best known for designing the White House Rose Garden.

She brought that sensibility to the Cape, shaping the grounds with native plantings, fruit orchards and formal gardens. In lieu of natural dunes, the Mellons famously imported 2,000 tons of sand to construct a 20-foot-high barrier between the house and the sea — a privacy measure that raised eyebrows in the press. 

“The newspapers had a field day describing the Mellons’ extravagance,” according to the biography “Bunny Mellon: The Life of an American Style Legend.”

The couple filled the house with fine art, often relocating masterpieces from their primary residence in Virginia each summer.

“He had some of the world’s greatest masterpieces,” Koch recalled. “I always wanted a Van Gogh, and he knew it, and would always — with just a touch of smugness—steer me into the room where it hung.”

Koch, now 85, purchased the estate for $19.5 million in 2013. 

A year later, he acquired an adjacent 10-acre property from the du Pont family and made that his primary Cape residence. He’s since used the Mellon home as overflow for family and guests, and at times rented it out for $25,000 a week.

“The main house remains largely as it was when the Mellons built it,” Koch told the Journal. “I wanted to maintain the house as I remembered it. Bunny Mellon’s designs and style still permeate the property.”

Indeed, many of Bunny Mellon’s touches remain intact — from baskets she hand-selected to the original layout of the gardens. The beach house near the shoreline has been left largely untouched since the days when the Kennedys would visit.

“It is important to me to preserve the home the way I remembered it when I used to visit Paul and Bunny, and maintain their influence and style over the estate,” Koch said in a separate statement to The Post.

The listing comes as Koch continues to scale back his Cape holdings. 

In addition to this sale, he’s asking $10.5 million for a nearby 1.75-acre parcel with a 3,700-square-foot house and dock, and last year listed another portion of the former Mellon estate for $16 million.

Koch’s real estate footprint extends far beyond the Cape. He owns a Palm Beach compound, a ranch in Paonia, Colo., complete with a faux Western town, and a sprawling estate near Aspen that is currently listed for $125 million.

In tandem with these property sales, Koch is offloading part of his renowned wine collection. Earlier this month, Christie’s hosted a three-day sale of nearly 8,000 bottles from his cellar. The event, titled The Cellar of William I. Koch: The Great American Collector, brought in $28.8 million, setting a North American record for a single-owner wine collection.

Despite broader market uncertainty, Koch’s listing still has a shot at drawing interest from buyers seeking heritage with privacy. 

“Great properties still sell quickly,” Zenas Crocker of LandVest, who is also marketing the listing, told the Journal. “Others may take a while or need price adjustments.”

He noted that the Northeast’s unusually rainy spring has slowed buyer momentum. 

“It’s not like, ‘It’s May 15, let’s go to the Cape,’” he said. “It’s 42 degrees and raining sideways.”

Still, the property remains a standout for those who value pedigree, privacy and provenance.

As Koch told The Journal, “He [Paul Mellon] taught me how to live with fine art in a wonderful, intimate way. My neighbors up here can thank him for their views of the Botero bronzes on my lawn.”