LANSING, Mich. – Maner Costerisan announced the merger of Baker Holtz, a respected Grand Rapids-based accounting and advisory firm, effective Jan. 1, 2026. The agreement, officially signed in late October, marks a major milestone in Maner Costerisan’s five-year growth vision to expand its service capabilities and deepen its presence across West Michigan.
The merger brings together two firms that share a strong commitment to integrity, exceptional client service, and community involvement. Baker Holtz’s three partners and 28 team members will join Maner Costerisan’s growing West Michigan operation, expanding the firm’s reach and resources for clients statewide.
“This merger is an exciting and strategic step forward for both of our firms,” said Trey Williams, CPA, president of Maner Costerisan (left). “We’ve been intentional about expanding in the Grand Rapids market through internal growth and now through acquisition. Partnering with Baker Holtz allows us to bring even greater access and resources to our clients—while continuing to foster the people-first culture that defines who we are.”
Maner Costerisan opened its Grand Rapids office in 2019 and is currently expanding to a 15,000-square-foot suite designed to support current team members, welcome Baker Holtz colleagues, and provide room for continued growth. The Baker Holtz team will remain in their current downtown Grand Rapids office throughout the 2026 tax season before relocating to Maner’s expanded office later in the spring.
“Joining forces with Maner Costerisan gives our clients access to expanded resources and additional expertise, without sacrificing the personal relationships and attention they’ve come to expect,” said Ryan Holtz, CPA, CGMA, managing partner of Baker Holtz (left). “Both firms share the same values and dedication to our people, our team, and West Michigan.”
Together, the combined firm will include more than 225 professionals focused on delivering comprehensive, forward-thinking financial and business solutions to clients across Michigan. The merger enhances the firm’s ability to drive growth, support local businesses, and give back to the communities it serves.
About Maner Costerisan
Maner Costerisan is a full-service public accounting and business consulting firm founded in 1906 and based in Lansing, Michigan. With nearly 120 years of experience and offices in Lansing and Grand Rapids, the firm provides a comprehensive range of services, including audit and assurance, tax planning and preparation, business consulting, technology solutions, and wealth management. The firm is nationally recognized including being named a Best Firm to Work For, Best Firm for Young Accountants, Best of the Best Firms, and a Top Firm to Watch, among other accolades. Maner Costerisan is dedicated to helping clients achieve their financial goals through innovative solutions, personalized service, and a commitment to excellence. The firm serves a diverse clientele across various industries, including manufacturing, nonprofit, government, health care, construction, and education. For more information, visit manercpa.com.
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