Another Connecticut savings bank is reorganizing to form a holding company, echoing a trend that took hold of the state earlier this year.

The state Department of Banking last week granted permission to Fairfield County Bank Corp. – a Ridgefield-based mutual savings bank that is the result of a 2004 merger of Fairfield County Savings Bank and Ridgefield Bank – to form a mutual holding company called Fairfield County Bank III MHC, with Fairfield County Bank II, a reorganized capital stock savings bank, as its wholly owned subsidiary. The bank also merged with Bank of Westport in 2004.

Fairfield County Bank Corp. now operates Fairfield County Bank and Ridgefield Bank as divisions of the company, but is not listed as a holding company on the Department of Banking Web site.

“[Forming a mutual holding company] will allow us to Â… raise additional capital if we choose to,” said Gary C. Smith, the bank’s president and chief executive officer. “But we won’t see any organizational changes … The bank has a 135-year tradition as a mutual bank and we will continue to serve the community in that fashion.”

The reorganization follows that of two other banks in Connecticut.

In March, the Simsbury Bank & Trust Co. formed SBT Bancorp, which gave the company the flexibility to issue trust-preferred shares to raise capital as it grows, although it did not do so at the time. That move took place after the 2005 passage of a law that allows banks to get involved in different businesses, such as insurance brokerage or trust companies.

In April, Farmington Savings Bank formed the holding company First Connecticut Bancorp. The bank’s executives and board also decided to take that action after last year’s law was adopted. Reorganizing into a holding company can facilitate diversification into related financial service lines and facilitate mergers and acquisitions, and it permits the repurchase of the bank’s own stock when that becomes necessary because of stock market valuation.

Fairfield County Savings Bank is a mutual bank that has $370 million in assets and operates seven offices in the towns of Darien, Rowayton, Norwalk and Fairfield. Ridgefield Bank is also a mutual bank, with $620 million in assets and six offices in the towns of Ridgefield, Redding, Wilton and Norwalk. The combined bank will remain mutual, have a combined $1 billion in assets and almost $100 million in capital. It will become one of the largest banks based in Connecticut.