Eastern Bankshares, the stock holding company for Eastern Bank, completed its acquisition of Century Bancorp, the stock holding company for Century Bank and Trust Company. The transaction is valued at approximately $642 million. Eastern and Century announced the transaction on April 7.

The acquisition became effective on Nov. 12 and Century shareholders will receive $115.28 in cash for each share of Century’s common stock they owned prior to the merger.

“We are excited to have completed — just over a year after Eastern’s initial public offering — the largest acquisition in our bank’s history and in doing so, to strategically expand Eastern’s presence in Boston and eastern Massachusetts,” Bob Rivers, CEO and chair of the board of Eastern Bankshares and Eastern Bank, said. “On behalf of everyone at Eastern, we are thrilled to welcome Century customers and employees and to carry on the exceptional customer service and community support cultivated by the Century team. This is an exciting milestone made possible thanks to the extraordinary talent of our teams, and we look forward to operating as a combined, larger organization offering an excellent customer service experience and being there for our customers’ financial needs.”

Upon completion of the acquisition, Century Bank merged into Eastern Bank, a wholly-owned subsidiary of Eastern Bankshares with locations serving communities in eastern Massachusetts, southern and coastal New Hampshire and Rhode Island.