Anton Collins Mitchell LLP announces new partners and promotions

New partners include Mark Lumsden and Ryan Sanger

Anton Collins Mitchell LLP (ACM) has announced that Mark Lumsden (Boulder) and Ryan Sanger (Northern Colorado) have been admitted to partner.

Lumsden joined ACM’s Boulder practice in 2012 after spending time at other local firms. He has a passion for assisting entrepreneurial companies in growth mode and assisting clients in reaching their goals through tax structuring and consultation. Lumsden’s experience includes a variety of industries including technology, manufacturing, real estate and construction. He is involved in many organizations in the Boulder community and is a graduate of the University of Colorado at Boulder.


Sanger is a native of Colorado and a graduate of Colorado State University. His expertise includes serving closely-held and privately-held companies in a variety of industries, including construction, real estate, manufacturing, beverage (craft breweries, distilleries, and wineries), distribution, professional service and retail. Sanger has also developed a specialty in state and local tax (SALT) consulting. He has a passion for youth issues as demonstrated through extensive philanthropic involvement.

“Mark and Ryan represent the talented, philanthropic, young leadership we attract at ACM,” said ACM President and Managing Partner Stacey Hekkert. “Team members like Mark and Ryan join ACM because of the opportunities and they stay because they can make significant contributions to firm culture and growth. These promotions reflect our commitment to clients and a vision for ACM’s future. We welcome them as partners and look forward to 2017 and beyond.”

Hekkert cited growth and the firm’s dedication to attracting and retaining the right people while announcing the following additions and promotions:

• Vivian Winston – Director (Denver)
• Kristin Holthus – Director of Finance and Operations (Denver)
• Scott Walker – IT Director (Denver)
• Christine Ludwig – Senior Manager (Boulder)
• Mei Lin Kis – Senior Manager – Joined November 2016 – (Denver)
• David Shellan – Senior Manager (Denver)
• Michelle Welch – Senior Manager (Denver)
• Kevin Baran – Manager (Denver)
• Samantha Bowden – Manager – Joined November 2016 – (Laramie)
• Cody Carter – Manager (Boulder)
• Audrey Pesses – Manager (Denver)
• Dawn Gustafson – HR Manager (Denver)
• Jessica Jalbert – Administrative Manager (Denver)

Anton Collins Mitchell LLP (ACM) is a full service public accounting firm headquartered in Denver with offices in Northern Colorado, Boulder and Laramie, Wyo. ACM provides audit, tax and consulting services to the Rocky Mountain Region’s entrepreneurial and middle market companies along with their owners, as well as public sector and philanthropic organizations. The firm’s membership in the BDO Alliance USA and 30 year relationship with BDO USA, LLP enhances its personal client approach with the resources of one of the world’s leading accounting services organizations. For more information about Anton Collins Mitchell LLP, visit

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