American billionaire and renowned collector William I. Koch will sell his unreplaceable 52-acre legacy Aspen ranch, Elk Mountain Lodge, at auction with Concierge Auctions in cooperation with Steven Shane of Compass.
One of the rarest offerings in the American West, the once-in-a-lifetime property, listed for $99 million, marks Koch’s long-established, successful approach to the sales within the auction format.
Bidding for Elk Mountain Lodge, located at 125 Rooney Circle, is scheduled to open July 7, 2026 and will culminate July 17, 2026 via the firm’s online marketplace, conciergeauctions.com.
“I’ve seen firsthand how auctions can unlock extraordinary outcomes across art, wine, and other one-of-a-kind holdings. 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,” said Koch.
“This is exactly how sophisticated collectors transact the world’s most marquee assets,” said Chad Roffers, CEO and Co-Founder of Concierge Auctions, whose firm has sold legacy land and ranch assets at auction for nearly two decades. “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.”
"Bill Koch has consistently demonstrated an extraordinary ability to identify, curate, and ultimately position rare assets for maximum interest,” said Shane. “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.”
Located in Aspen’s coveted Castle Creek Valley, the approximately 25,277-square-foot compound spans 52.2± acres and includes eight structures reflecting the finest craftsmanship and high-end finishes. At the heart of the estate is a main residence designed by award-winning Colorado architect Rowland+Broughton, complemented by seven thoughtfully positioned guest cabins, including a state-of-the-art fitness center. The property features sweeping views of the Elk Mountain Range, two serene ponds, river frontage, an eight-car garage, and frontier-inspired architecture blending refined luxury with modern sustainability. Situated just 11 miles from downtown Aspen, the estate offers a rare combination of grandeur, privacy, and proximity to one of the world’s most coveted luxury destinations. Renowned for its four ski mountains, internationally recognized cultural institutions, acclaimed dining scene, year-round outdoor recreation, and unparalleled alpine lifestyle, Aspen continues to rank among the most desirable markets globally.
All photography credited to Shawn O’Connor.
As part of Concierge Auctions' Key For Key® giving program in partnership with Giveback Homes, the closing will result in funding toward new homes built for families in need.