Cambridge Bancorp, the holding company for Cambridge Trust Co., will make its second merger in a year when it acquires Wellesley Bancorp Inc., the holding company for Wellesley Bank.

The all-stock deal announced on Dec. 5 is valued at approximately $122 million. The purchase price comes to $45.54 per Wellesley common share based upon Cambridge Bancorp’s 10-day average closing price of $78.53 as of Dec. 4.

Cambridge Trust has 16 locations in Cambridge, Boston, Belmont, Lexington, Weston, Concord and New Hampshire. Wellesley Bank has six branches in Wellesley, Newton, Needham and Boston. Cambridge Trust had total assets as of Sept. 30 of $2.8 billion. Wellesley Bank has assets of about $980 million.

The same day the merger was announced, Cambridge Bancorp announced it was offering 479,000 shares of common stock to the public at a price of $73 per share. If successful, the offering will raise $33.2 million for the company after underwriting discounts and commissions. In a statement, the company said it plans to use the proceeds for “general corporate purposes, including funding organic growth and potential acquisitions.”

Cambridge Trust expanded into New Hampshire last year by acquiring Optima Bank. That deal was valued at approximately $67 million.

“We are pleased to announce the strategic combination of Cambridge Trust and Wellesley Bank, who are both dedicated to providing individuals, families and businesses with exceptional personal attention and custom financial solutions,” Denis Sheahan, CEO of Cambridge Trust, said in a statement. “Wellesley Bank is a well-managed, financially strong and growing company located in attractive markets. The combination strengthens the position of Cambridge Trust in Greater Boston and is a logical extension of our market. We look forward to welcoming the talented Wellesley Bank team to Cambridge Trust.”

Thomas Fontaine, chairman, president and CEO of Wellesley Bank, will join the combined company in the role of chief banking officer and director. He will also be one of three Wellesley directors to join Cambridge Bancorp’s board of directors.