Massachusetts-based United Financial Bancorp and CNB Financial Corp have signed an agreement and plan of merger, pursuant to which CNB Financial will merge with and into United Financial and Commonwealth National Bank, a wholly-owned subsidiary of CNB Financial Corp will merge with and into United Bank.

United Financial will acquire the outstanding shares of CNB Financial for an aggregate purchase price of approximately $25 million, which includes outstanding stock options and warrants. Upon completion of the merger, the pro forma company will have approximately $1.5 billion in total assets, approximately $1.0 billion in deposits, more than $220 million of tangible common equity.

Richard Collins, President and Chief Executive Officer of United Financial said: “The strategic combination of our two companies marks United Financial’s initial expansion into Worcester County. We look forward to serving the greater Worcester community.”

Charles Valade, President and Chief Executive Officer, CNB Financial, said: “CNB Financial’s Board of Directors determined that combining with United Financial is the right partnership for our shareholders and our franchise. We are very excited about the prospects for the combined organization. We appreciate the interest in our franchise shown by Berkshire Hills Bancorp. However, after thorough due diligence, we believe that a merger with United Financial will result in the greatest value for our shareholders.”

It expects to complete the transaction in the fourth quarter of 2009. However, it is subject to approval. The holding company will remain headquartered in West Springfield, Massachusetts.