Lansing, Mich.-based IPA 200 firm Maner Costerisan (FY24 net revenue of $46.36 million) has announced that Baker Holtz, a Grand Rapids-based accounting and advisory firm, will join the firm effective January 1, 2026. The agreement was finalized in late October and expands Maner Costerisan’s service capabilities and regional footprint in West Michigan. 
“Joining forces with Maner Costerisan allows us to deliver even greater value to our clients without sacrificing the personal relationships and attention they’ve come to expect,” said Ryan Holtz, CPA, CGMA, managing partner of Baker Holtz. “Both firms share the same values and dedication to our people, our team and the West Michigan community.”
Founded in 1979, Baker Holtz serves small and midsize businesses as well as individuals and families. The firm’s three partners and 28 team members will remain in their current downtown Grand Rapids office through the 2026 tax season before relocating to Maner Costerisan’s expanded Grand Rapids office in the spring.
Maner Costerisan, which opened its Grand Rapids office in 2019, is expanding into a new 15,000-square-foot space that will accommodate current staff, new colleagues from Baker Holtz and future growth. The combined firm will have more than 225 professionals serving clients statewide.
“This merger is an exciting and strategic step forward for both of our firms,” said Trey Williams, CPA and president of Maner Costerisan. “Partnering with Baker Holtz allows us to strengthen our presence in West Michigan while continuing to foster the people-first culture that defines us.”
