Who We Are

Quan Mac

Co-Chief Executive Officer & Co-Chief Investment Officer

QUAN H. MAC brings nearly 30 years of experience advising high-net-worth families, institutional investors, and family offices on complex investments, generational transitions, and long-term wealth stewardship.

  • Quan has started and led investment platforms at Greenville Asset Management as CEO and CIO, and previously as president and CEO of Greenville Partners, a single family office. Her earlier roles include Managing Director at Legacy Trust and Director of Global Private Equity at RDV Corporation. She began her career at UBS Global Asset Management (Brinson Partners), Merrill Lynch Investment Managers (Hotchkis and Wiley), and Transamerica Retirement Services, developing a global strategic perspective.

    Quan currently serves as a Senior Advisor to Pritzker Alternative Strategies, Advisory Board Member for The Riverside Company, Trustee to the Hg Foundation, and Member of the Steelcase Foundation and Michigan Health Endowment Fund Investment Committees. Appointed by Governor Gretchen Whitmer, Quan also serves on the Michigan Health Endowment Fund board, supporting initiatives addressing infant mortality, food access, wellness, and health technology for vulnerable populations. She also sits on  the steering committee and advisory council for the University of Chicago Booth School of Business’s Family Office Initiative and Northwestern University’s Council of 100.

    Quan holds an MBA from the University of Chicago Booth School of Business and a bachelor’s degree from Northwestern University. She is a Registered Investment Representative and Series 65 license holder. Based in Grand Rapids with her husband and three children, she enjoys reading, theater, culinary arts, travel, card and board games, and sports, especially soccer.

Kathleen Vogelsang, CFA

Co-Chief Executive Officer & Co-Chief Investment Officer

KATHLEEN B. VOGELSANG, CFA is a respected investment executive with over 30 years of experience, Kathleen has built and led significant investment programs for endowments, family offices, and high-net-worth clients.

  • For the last two decades, Kathleen served as Chief Investment Officer of Van Andel Institute, a world-renowned biomedical research organization. She joined the Institute in 2005 and built its $2 billion investment program from the ground up. Prior to that, she served as Vice President and Senior Portfolio Manager in the Wealth Management Group at Fifth Third Bank, where she managed investments for the bank’s most prominent private clients.  Prior to Fifth Third, Kathleen served as the Director of Investments at JVA Enterprises, a private family office, where she established the organization’s investment office and managed a multi-asset investment portfolio, including investing its in-house fixed income portfolio.

    Kathleen also plays an active role in Michigan’s philanthropic and civic communities. Her current commitments include serving on the investment committees for The Van Andel Institute, Grand Valley State University Endowment Fund, the Frey Foundation, the Council of Michigan Foundations, and Padnos Iron and Steel Retirement Plans. In addition, she contributes as a board member of Gift of Life Michigan and the Grand Valley State University Foundation Executive Committee. Earlier in her civic leadership, she chaired the board of the highly regarded Grand Rapids Community Foundation, leading the search for a new President ahead of her 2024 departure and served on the National Board of the World Affairs Council of America.

    Her leadership has earned wide recognition: Crain’s Detroit named her one of Michigan’s 100 Most Influential Women (2016) and one of its Notable Women in Finance (2020). That same year, the Association to Advance Collegiate Schools of Business honored her as one of its Influential Leaders — a reflection of her impact across both public and private sectors.

    Kathleen earned both a Bachelor of Business Administration in Finance and an MBA from Grand Valley State University. She is a Registered Investment Representative and holds the Chartered Financial Analyst (CFA) designation from the CFA Institute. She lives in Grand Rapids, Michigan with her husband, where she balances a love for golf, boating, theater, and travel. 

The Bostwick Story

The story of Bostwick Investment Consulting is one rooted in decades of shared experience, ten years of friendship, and a collective vision for delivering investment advice defined by objectivity and enduring trust. That vision traces back to Bostwick Avenue in Grand Rapids, Michigan; a meaningful launch point for both founders that continues to shape their work.

In the late 1970s, Quan Mac arrived in the United States among the “boat people” refugees from Vietnam and was embraced by the community’s generosity that continues to inspire her dedication to service. Starting from humble beginnings, Kathleen Vogelsang forged a remarkable career after attending college as a non-traditional student with small children.

Together, through their distinguished careers—Kathleen as the architect and longtime CIO of the $2 billion Van Andel Institute endowment, and Quan as the CEO and CIO of Greenville Asset Management, a private investment firm that serves a multi-generational family—they cultivated a shared conviction: discerning investors deserve investment advice that is both truly independent and deeply personal and investment managers should have access to candid and honest feedback and advice.

  • After decades of navigating the complexities of high-net-worth, institutional, and family office investing, Kathleen and Quan saw firsthand how challenging it can be for investors to find expert counsel unclouded by sales incentives or asset-gathering practices. They recognized that managing substantial wealth is an inherently nuanced endeavor, requiring careful, discerning oversight. It requires not just technical expertise, but also trust, empathy, and a long-term vision that honors both the present and the future.

    Motivated by the desire to make their collective expertise more accessible and shaped by their own journeys, Kathleen and Quan joined forces to create the kind of firm they themselves would trust: one grounded in prudent and independent decision-making, integrity, discernment, and attractive risk-adjusted returns across market cycles.