A year and a half ago, the billionaire Bill Koch spun his massive Aspen estate on the market for $125 million, making it one of the most expensive homes for sale across the globe. That hefty sum likely wasn’t palatable for most people, and the price has since dropped to $99 million—no measly asking price either.

Now, still searching for a buyer, Koch is putting the 52-acre spread up for auction. From July 7 to 17, you’ll have chance to bid on Elk Mountain Lodge, as the property is known. Concierge Auctions is handling the sale, alongside Steven Shane of Compass, who’s held the listing since it debuted in January 2025.

“I’ve seen firsthand how auctions can unlock extraordinary outcomes across art, wine, and other one-of-a-kind holdings,” Koch said in a statement. “The Aspen property has been an incredibly meaningful place for my family, but the time has come for someone else to enjoy it, and I look forward to seeing its next chapter unfold.”

Koch acquired the former dude ranch for $26.5 million back in 2007. He went on to add to the acreage over time and sold off part of it in 2020 for $14.5 million. What remains now is a compound sprawling across eight structures and more than 25,000 square feet of living space. The main residence, designed by the local firm Rowland+Broughton, is paired with seven guest cabins; altogether they offer a whopping 15 bedrooms and 17 bathrooms.

The 16,631-square-foot main house sports a frontier-inspired aesthetic, interpreted through the use of flagstone floors, wood-paneled walls, and plenty of fireplaces for keeping warm. Highlights of this abode include a dining room that seats 20, climate-controlled wine storage, and a screening room that can pull double duty as an altitude-acclimation chamber. The biggest guest cabin is outfitted with a state-of-the-art fitness center, while elsewhere you’ll encounter an eight-car garage, two ponds, hot tubs, and both hiking and cross-country skiing trails.

Koch, who founded Oxbow Carbon, is part of the family behind Koch Industries. Along with his business pursuits, he’s also an accomplished sailor who won the America’s Cup in 1992. When he first listed Elk Mountain Lodge for sale last year, he also had properties in New York City, Palm Beach, Cape Cod, and Paonia, Colorado.

Click here to see all the images of Bill Koch’s Aspen estate.