Framingham Co-operative Bank and Natick Federal Savings Bank have agreed to merge and form one unified mutual bank.

The combined bank will consist of three full-service banking offices, two located in Framingham and one in Natick, with an administration center in Framingham. No jobs will be eliminated as a result of the merger, the banks said in a joint statement.

"Increasing regulatory and operational expenses make it very difficult for the small community bank to thrive," said Brian K. Peoples, president and chief executive officer of Natick Federal Savings Bank. "The consolidation will maintain our strength as a well-capitalized mutual institution with the size necessary to compete in today’s banking environment."

The joining of Framingham Co-operative Bank and Natick Federal Savings Bank is a consolidation of two mutual banks into one institution. The assets of the two banks will be blended, and the employees of the two banks will be combined. There are no stockholders or holding companies involved.

"Retaining a mutual charter was very important to the managements of both banks," said Mark R. Haranas, president and chief executive officer of Framingham Co-operative Bank. "The banks serve contiguous markets and share major supporting vendors. This will allow the new bank to increase services to both markets, while reducing expenses in many key non-employee areas."

The bank will operate under a Massachusetts co-operative bank charter, with Haranas serving as president. Peoples and three other members of the Natick Federal Savings Bank board of directors will join the current members of the Framingham Co-operative Bank board of directors to form the governing board at the new bank. In addition, all deposits at the new bank will be insured in full through a combination of coverage from the Federal Deposit Insurance Corporation (FDIC) and the Share Insurance Fund (SIF) of Massachusetts.

Framingham Co-operative Bank, a state-chartered mutual co-operative bank founded in 1889, had $398 million in assets as of Dec. 31. Natick Federal Savings Bank, a federally chartered mutual savings bank formed in 1886, had $156 million in assets as of Dec. 31, 2011.

The merger is subject to a process that includes approval by regulatory agencies. It is expected to be completed during the third quarter.