NORWICH – M&T Bank Corporation and Partners Trust Financial Group, Inc. announced Thursday that they have entered into a definitive agreement under which Partners Trust will merge into M&T in a transaction valued at approximately $555 million.

M&T is headquartered in Buffalo and has $57.9 billion in assets, while Partners Trust has $3.7 billion in assets and is based in Utica.

There are no M&T’s in Chenango County and only one Partners Trust, which is located in Norwich’s North Plaza. It will become an M&T within the next four to six months, said Chet Bridger, a spokesman for the Buffalo-based bank.

“For the individual customer, the necessary welcome kit from us with everything they need will be sent out after the acquisition is closed. Everything will remain business as usual,” Bridger said Thursday in a telephone interview. “For our business customers, we are really excited to come into Norwich. Helping small businesses grow is one of our strong suits.”

M&T is rated as one of the top small business lenders in New York state by the Small Business Association.