Plante Moran in Southfield, a large audit, tax, consulting, and wealth management firms, has acquired Boston-based accounting and advisory firm Tonneson + Co., effective July 1. Terms of the deal were not disclosed.
Among the largest 25 accounting firms in Boston, Tonneson + Co. has a 50-year history providing audit, tax, and advisory services. With a team of more than 100 professionals and a service footprint that spans multiple industries and international markets, the firm has built its reputation on a client-first philosophy.
“We’re excited to join forces with Plante Moran — a 100-year-old, staunchly independent firm known for its award-winning culture,” says Rick Mastrocola, CEO of Tonneson. “This partnership allows our combined firms to further enhance the capabilities we offer both clients and staff while preserving the unique culture and relationships that have defined Tonneson and Plante Moran for decades.”
In 2024, Tonneson + Co. was honored by Accounting Today in its “Best Accounting Firms to Work For” list for the seventh consecutive year.
“For 100 years, Plante Moran has prioritized long-term stability and client success, which has fueled the firm’s steady growth,” says Jason Drake, managing partner of Plante Moran. “Tonneson’s shared values and vision for the future make them an ideal partner. We’re excited to welcome their talented team and expand our presence in Boston.”
Since its founding in 1924, Plante Moran has grown from a sole accounting practitioner in a Detroit office to a billion-dollar firm with nearly 4,000 professionals serving clients around the globe.
For more information about Plante Moran, visit plantemoran.com.
For more information about Tonneson + Co., visit tonneson.com.
