Most people have probably heard of the Koch brothers. You might even know their first names: Charles and David Koch. Charles Koch, with a net worth of $73 billion, is one of the richest people in the world. His younger brother, David Koch, died in 2019. Today, David’s widow, Julia Flesher Koch, has a net worth of $81 billion, making her one of the richest people on earth and the second-richest woman in the world, behind only Walmart heiress Alice Walton.
But what a lot of people do not realize is that there were actually four Koch brothers.
Charles and David were only half the story.
The Other Two Koch Brothers
The other two sons of Koch Industries founder Fred C. Koch were Frederick, known as Fred Jr., and William, better known as Bill. Fred Jr., the eldest of the four, died in 2020 at the age of 86. Bill Koch is still alive. He is also a billionaire. But despite the last name, he is not worth $70 billion or $80 billion. He’s worth around $2 billion. Bill is not involved in Koch Industries. He has not been involved in the family business for decades.
And for much of his adult life, he and Fred Jr. were locked in one of the nastiest billionaire family feuds in American business history.
The Family Feud That Split The Fortune
After Fred Koch Sr. died in 1967, ownership of the family company eventually became the subject of a brutal fight among his four sons. Charles took control of the business, David sided with him, and Bill and Fred Jr. ended up on the outside. In the early 1980s, after a failed attempt to challenge Charles’ control, Bill and Fred Jr. sold their stakes back to Charles and David. Depending on the account, the buyout was worth roughly $700 million to $800 million, and the transaction left Charles and David in control of what became one of the largest private companies in America.
Bill and Fred Jr. later claimed they had been shortchanged. What followed was nearly two decades of litigation, accusations, countersuits, and family bitterness that also eventually had a cameo from Anna Nicole Smith.
The fight finally settled in 2001, long after the brothers’ personal relationships had effectively collapsed. When Fred Jr. would periodically see his younger brother David and NYC philanthropic events, they reportedly would not even look at each other, let alone say hello.
Bill Koch took his life in a very different direction. He built his own fortune through energy, investments, Oxbow Carbon, collectibles, sailing, wine, Western art, and trophy real estate. He also won the America’s Cup in 1992. And that brings us to Aspen.
The $99 Million Aspen Auction
Bill Koch is now preparing to auction off one of his most spectacular properties: Elk Mountain Lodge, a 52-acre Aspen compound that was once listed for $125 million, later reduced to $99 million, and is now heading to auction in July 2026. Bidding is scheduled to open July 7 and run through July 17 through Concierge Auctions, which is handling the sale alongside listing agent Steven Shane of Compass.
Koch bought the former dude ranch in 2007 for $26.5 million. He later expanded the property, then sold off a portion of the acreage in 2020 for $14.5 million. What remains is still enormous: 52 acres, eight structures, more than 25,000 square feet of total living space, 15 bedrooms, 17 bathrooms, and the kind of amenities that make a $99 million Aspen listing feel only slightly absurd.
Inside Elk Mountain Lodge
The centerpiece is a 16,631-square-foot main lodge designed by Aspen architecture firm Rowland+Broughton. The home leans hard into high-end frontier fantasy: flagstone floors, wood-paneled walls, oversized fireplaces, a dining room that seats 20, wine storage, a screening room, and a primary suite built for someone who clearly never planned to check Zillow before making a purchase.
Elsewhere on the compound are seven guest cabins, an eight-car garage, two ponds, hot tubs, hiking trails, cross-country skiing trails, and a fitness center tucked inside one of the cabins.
And because this is Aspen, and because this is a Koch brother, the property also has a screening room that can double as an altitude-acclimation chamber. Here is a video tour of Elk Mountain Lodge:
A Very Koch Real Estate Story
That last detail is exactly why this is not just a real estate story. It is a Koch story.
Bill Koch may be the forgotten Koch brother in the popular imagination, but he has lived the kind of billionaire life that almost sounds fictional: a family empire battle, a nine-figure buyout, decades of lawsuits against his own brothers, an energy fortune of his own, an America’s Cup victory, and now a $99 million Aspen ranch headed to auction.
Charles and David got Koch Industries.
Bill got the yacht, the art, the wine, the mountain compound, and the distinction of being one of the few people on earth who can be described as both a billionaire and the “less wealthy” Koch brother.
