Mark J. Haldeman

Mark has consistently been in the top 5% of all Brokers for sales in the Aspen area and because of his accomplishments, has earned the respect of his peers as well as his customers and clients. In recent years, Mark has represented the Sellers of the highest priced single-family home sales in the state of Colorado on two separate occasions. The closing of Aspen’s Summit House for $29.5 million was the most expensive home sale in Colorado in 2015. In 2011, he brokered both the listing and selling side of a $20,750,000 Aspen estate which was the highest priced home sale in the state of Colorado that year.

Mark moved to Aspen in 1984, at age 27, to open Mark Justin, which became a successful retail-clothing store/guide and outfitting service for over 10 years. In 1995, he had the opportunity to acquire the building that housed his operations and subsequently commenced what has become a 25-year real estate career totaling over $800 million in residential sales. He has also been involved in Aspen’s commercial real estate market with the development/restoration of the Wheeler Block, the A.G. Sheppard, and Prada buildings. He was honored by Aspen’s Historic Commission for his work.

Mark and his wife, Laura, spend time in South Florida during the “off-seasons.” Their son James, is a Sous Chef at John Besh’s and Aaron Sanchez’s collaborative restaurant, “Johnnie Sanchez” in New Orleans, LA.

Jennifer Banner

Jennifer has fifteen years of experience advising buyers and sellers of luxury Colorado real estate. She has a keen eye for quality and understands what creates value for her clients. Jennifer is a tireless worker and has a knack for coming up with creative solutions to challenges that inevitably arise in complex transactions.

She also has extensive experience working with developers of Aspen real estate, having represented a successful 100-unit townhome development with total sales in excess of $100M. She was closely involved in all aspects of the development including site identification and acquisition, financial modeling, interior design, and project marketing and pre-sales.

Whether looking to buy or sell, you will need a teammate who can help you understand the nuances of the local neighborhoods, interpret the data, and guide you through the process. Jennifer’s goal is to arm you with the knowledge you need to make smart real estate decisions.

Jennifer is a Dallas, Texas native. She was educated at Phillips Exeter Academy and the University of Wisconsin, Madison. She is a former Division I athlete and an Ironman. She starts every morning on her Peloton and in her spare time, volunteers as a coach for Aspen Junior Hockey and enjoys skiing, hiking, cycling, and traveling with her husband, Tom.


Established in 1976 as a logical extension of Sotheby’s fine art auction services, Sotheby’s International Realty has since developed into the world’s premier luxury residential real estate brokerage offering tremendous advantages. With expertise on the local level, combined with our access to important international markets, we ensure that the homes we represent receive the far-reaching exposure they deserve.

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