Maner Costerisan Announces Principal Promotions, Addition to Board of Directors

Katie Hamilton, CPA, named to board, five Maner team members join accounting firm’s principal group

LANSING, Mich. – Maner Costerisan, a full-service public accounting, technology, wealth management, and business consulting firm, is pleased to announce five team members have been promoted to principal and Katie Hamilton, CPA, has been appointed to the board of directors effective Jan. 1, 2024.

Katie Hamilton, CPA, principal, oversees Maner’s tax department and is responsible for the firm’s tax growth strategy and client service. Additionally, she provides expert counsel on income, estate, and gift tax planning for the firm’s wealth management clients. Hamilton joined Maner in 2019 and, one year later, was instrumental in launching Maner Wealth, the firm’s wealth management service, which was recognized in 2023 by Accounting Today as a Top Firm nationally based on assets under management. She was also named a 10 Over the Next Ten Award recipient in 2019 by the Lansing Regional Chamber of Commerce, which recognizes the top young professionals in the region.

“Katie is tireless in finding ways to support our clients and provide solutions tailored to their unique needs. She’s been essential to the growth and development of our wealth management practice,”  said Trey Williams, CPA, president of Maner Costerisan. “Katie is smart, humble, and she’s committed to making our firm a great place to work for those in the tax department and others across the firm. We are delighted to welcome her to this new role on the board, where she will continue to inspire others.”

The promotions of Jessica Fleet, Joel Korson, Nick Kossaras, Stephanie Kossaras and Clayton Stiffler to principal reflect their professional expertise, leadership qualities, and the confidence earned by the firm and its clients, as well as the next phase of leadership for the award-winning firm.

Jessica Fleet, CPA, CHFP, joined Maner Costerisan in 2014 and works in the firm’s accounting and outsourced solutions department, where she provides services to clients across various industries, including healthcare and small and midsize businesses. Fleet graduated from Saginaw Valley State University with a bachelor’s degree in professional accounting.

Joel W. Korson, CPA, CCIFP,  provides accounting, audit, tax, and consulting services to small and midsize business clients, particularly in the construction and manufacturing sectors. Korson started at the firm as an intern in 2013. He received a bachelor’s and master’s degree in accounting from Michigan State University.

Nick Kossaras, CPA, joined the firm a decade ago after receiving his bachelor’s and master’s degrees in accounting from Michigan State University. He currently works in Maner’s audit department and specializes in providing audit services to Maner’s affordable housing and education clients. He is deeply involved with the audit department’s strategic planning and is currently researching next-generation audit software, which will lead Maner into the future.

Stephanie Kossaras, CPA, HCCP, specializes in affordable housing and multi-state entities and provides tax advise, planning, and preparation to the firm’s for-profit clients. She works in Maner’s tax department and is passionate about helping clients in the affordable housing sector, earning her Housing Credit Certified Professional (HCCP) designation.  Kossaras also supports the firm’s employee benefit plan specialty and helps clients ensure their retirement funds are appropriately managed through audits. She is a graduate of Michigan State University.

Clayton Stiffler, CPA, CCIFP, joined Maner Costerisan in 2014 and currently provides accounting and outsourcing expertise to clients in various industries, including small and midsized businesses, cannabis, and construction. He leads the firm’s construction team and is one of less than 2,000 professionals nationwide to receive the Certified Construction Industry Financial Professional (CCIFP) designation. Clayton graduated from Michigan State University with a bachelor’s and master’s degree in accounting.

“We are excited to welcome Jessica, Joel, Nick, Stephanie, and Clayton to Maner’s principal group,” said Williams. “Their expertise, insight, and passion for our industry are tremendous assets to our clients, and their contributions as principals will continue to shape our firm positively now and into the future.”