Lloyd Hamm, CEO of River Run Bancorp and Jonathan Dowst, president of River Run Bancorp, pose for a photo. Photo courtesy of River Run Bancorp

Another mutual holding company combination has gotten the green light to go ahead, this time in the Merrimack Valley.

Haverhill-based Pentucket Bank and Newburyport Bank announced Friday they’d been given regulatory approval to combine their mutual holding companies into one, River Run Bancorp. The common holding company will run both banks as separate, independent community banks through a shared services organization, letting the two entities streamline operations and back-office space, and offer new “advanced products and services,” the banks’ announcement said.

In addition, the banks indicated they will be investing in several existing “bank locations” that will make space for yet more banks to join the partnership in the future, should any seek to do so.

River Run joins Hometown Financial Group, which combines Abington Bank, bankESB and bankHometown under one shared-services entity, and Dedham Savings and South Shore Bank’s 1831 Bancorp as the latest shared-services mutual holding companies in Massachusetts as numerous small mutual banks look for ways to achieve the scale necessary for long-term survival without giving up mutuality.

The new entity will have nearly $3 billion in assets. Lloyd Hamm, Newburyport Bank’s president and CEO, will be CEO of the combined holding company, and Pentucket Bank’s president and CEO, Jonathan Dowst, will be president and then succeed Hamm at his retirement. Newburyport’s and Pentuckets corporators will continue in their roles overseeing the lenders, but as separate advisory boards for the two subsidiary banks and together as corporators for River Run.

“We are thrilled to have received formal regulatory approval from the Federal Reserve Bank of Boston and the Massachusetts Board of Bank Incorporation for the formation of River Run and to begin officially operating under our new structure. The formation of River Run is a testament to the strength and solidarity of both independent banks, which makes our partnership under River Run so powerful,” Hamm said in a statement. “We believe this strategic partnership will yield countless benefits for the employees, customers, and communities of both banks.”

Pentucket and Newburyport employees have already been working to integrate back-office functions, the banks said, including choosing a joint core provider

“The process to come together as one River Run team has proven our team’s talent and dedication to our customers, communities, and one another,” Dowst said in a statement. “We are thankful to our Board and Corporators for their support and trust in our team to bring River Run to reality. There is a tremendous amount of work being done in the background as we prepare for the official launch of River Run, and this is what provides the foundation for the long-term sustainability of both Banks for the benefit of all of our customers, employees, and communities. This is the most important part, this is why we are here.”