Billionaire industrialist Bill Koch is taking his sprawling Aspen retreat to auction after failing to secure a buyer at nearly nine figures, according to a press release. 

Koch’s 52-acre Elk Mountain Lodge estate, tucked into Aspen’s Castle Creek Valley about 11 miles from downtown, is headed to a 10-day online auction through Concierge Auctions beginning July 7. The compound had previously been listed for $125 million before receiving a price cut to $99 million.

The seller is no stranger to the auction world. Koch, the founder of Oxbow Carbon and a prominent collector of fine art and wine, has long used auction houses to move trophy assets. This time, he is betting the competitive format will generate fresh momentum for one of the largest privately held residential compounds in the Aspen area.

“I’ve seen firsthand how auctions can unlock extraordinary outcomes across art, wine and other one-of-a-kind holdings,” Koch, 86, told Bloomberg in an email. “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.”

The ranch spans more than 25,000 square feet across eight structures, including a main lodge designed by Colorado architecture firm Rowland+Broughton and seven guest cabins spread across the property. 

The estate also includes private trails, ponds, river frontage, hot tubs, an eight-car garage and a fitness center, all positioned against panoramic views of the Elk Mountain Range.

Koch began assembling the estate in 2007 after purchasing the property for $26.5 million, according to property records. The land has lived several lives over the decades, first as a homestead, later as a dude ranch in the 1930s, and eventually as a wedding and event venue before Koch transformed it into a private family compound.

“Aspen is extraordinary, particularly in the location of Elk Mountain Lodge,” Koch said in an email to Bloomberg. “We were able to create the perfect space for our family that felt like home.”

The estate arrives on the market during a changing moment for Aspen’s luxury housing sector. The mountain enclave experienced a pandemic-era real estate frenzy, with total sales reaching $2.5 billion in 2025, according to the Estin Report. 

Activity has cooled more recently, however, with buyers regaining negotiating leverage after years of intense competition.

Still, brokers say opportunities to acquire a property of this scale in Aspen remain exceptionally limited.

“This is exactly how sophisticated collectors transact the world’s most marquee assets,” Chad Roffers, CEO and co-founder of Concierge Auctions said in a statement. “Bill Koch understands better than anyone that a defined timeline paired with global exposure is the most powerful strategy for truly one-of-a-kind assets like this one.”

Steven Shane of Compass, who is representing the listing, described the ranch as one of Aspen’s most difficult estates to replicate given current land and development constraints.

“This unduplicatable ranch stands among the most significant property offerings in Aspen, not only because of its scale and craftsmanship, but because estates of this caliber and provenance simply cannot be replicated today,” Shane said. 

The property includes eight bedrooms and 10 bathrooms spread throughout the compound, along with river access and direct proximity to Aspen’s ski terrain and downtown core.

Meanwhile, this isn’t the first time Koch has hit the auction scene in recent years. Last summer, he auctioned historic wine vintages from his private collection, which reached up to $180,000 a bottle.