Ion Bank will be merging with Boston-based The Cooperative Bank, with the latter operating as a division of the Connecticut-based institution.

The merger will result in Ion Bank having approximately $3.3 billion in assets and an additional four branches in the Greater Boston area. As a part of the transaction, a new charitable foundation dedicated to supporting the communities served by the Massachusetts institution will be established with an initial contribution of $2.5 million.

Upon completion of the transaction, current TCB President and CEO John Battaglia will join Ion Bank and become president of the TCB division. Heather Jenkins and Clayton Samuels, each currently TCB directors, will be offered a position on Ion’s board of directors. David Rotatori will continue as president and CEO of Ion Bank.

“TCB has been serving its customers and communities for the past 128 years. By joining with Ion Bank, we recognized an opportunity to expand our product and service offerings with another strong mutual financial institution,” Battaglia said in a statement. “Ion Bank’s history and vision made them the perfect fit for TCB, our employees, our customers and our communities.”

TCB has four locations in four Boston neighborhoods and approximately $543 million in total assets.

This merger comes after Ion Bank acquired NVE Bank in New Jersey in April 2025. That merger bumped Ion to approximately $2.7 billion in assets.

The merger with The Cooperative Bank is expected to close in the fall of 2026, subject to regulatory approval and the completion of other customary closing conditions.

“We are thrilled to add TCB as a division of Ion Bank,” Rotatori said in a statement. “This merger reflects Ion Bank’s core mission as a mutual institution to deepen its commitment to local communities, expand access to meaningful financial services, and partner with likeminded organizations that share its values of trust, service and long-term community investment.”