Five Massachusetts banks in the past four years have changed their federal regulator, making the leap from the Federal Deposit Insurance Corp. – the regulator for 148 of the state’s 205 banks – to the Federal Reserve.

Their reasons range from communication, to concerns about the FDIC’s dual deposit insurer and bank examiner role, to – in the case of one of the five, Investors Bank & Trust, which just switched last October – the belief that the Fed simply was the more appropriate regulator for the non-retail custodial bank.

But there are common threads. The shifts are taking place in an arena many thought was set in stone. And as more banks hear change is possible, more are becoming interested.

“I think an awful lot of people have never considered a switch,” said Charles P. Monaghan, president and chief executive officer of Boston-based Mercantile Bank and Trust Co., which changed from the FDIC to the Fed in 2004. “But I hear anecdotal evidence that more people are joining [the Fed] and more people are thinking about it.”

Monaghan said he had never considered changing his bank’s regulator – even though the Fed has regulated its holding company for years – because he never thought of that agency as a small-bank regulator. Then, a Federal Reserve employee mentioned the possibility to him.

Like the four other Massachusetts banks that have changed regulators from the FDIC to the Fed, Mercantile Bank – which has $128 million in assets – is state-chartered, meaning it’s under the supervision of state regulators as well as either of the two federal entities. Many state-chartered community banks think switching from the FDIC, which generally regulates them, to the Fed means changing that charter to the less-familiar national one.

But that isn’t the case, said Bank of Easton President and Chief Executive Officer Thomas Caron, whose $92 million bank switched in 2004.

His colleagues at the $181 million Marblehead Savings Bank and the $152 million Northampton Co-Operative Bank, which changed from the FDIC to the Fed in 2003 and 2006, respectively, also thought or were advised that the switch also would mean a charter change, but found it wasn’t so.

For the past 25 years and until very recently, the Federal Reserve Bank of Boston’s main regulated institutions were Massachusetts bank holding companies (entities banks form when they want to merge) and State Street Bank, formerly a commercial bank but today a non-retail, custodial bank that holds and invests mutual fund assets.

But a hefty bank-merger appetite in the past 20 years brought the number of banks down, from 13,000 nationwide to about 8,600 today. In the process, many community banks, including Fed member banks, merged out of existence.

It was only in 2003, when then-Marblehead Savings Bank Chief Executive Officer Edward Cowden decided to switch, that the first community bank in the state since the 1980s came back into the Federal Reserve fold.

The Fed always has regulated community banks in New England, noted Thomas L. Lavelle, vice president and spokesman for the Boston Fed.

Getting a firsthand look at that side of the industry helps the bank fulfill another of its primary roles, which is to set monetary policy, he said.

“The Fed feels community banks play an important role in both the industry and the economy, and member banks help enhance our perspective on the industry as a whole,” he explained.

FRB-Boston has developed a brochure that it gives to banks expressing interest in joining.

Massachusetts Bankers Association President Daniel J. Forte said the ability to switch regulators, from an industry perspective, is a good thing. When banks have options, he noted, “it forces all the regulators to step back and say, ‘What are we doing right, and how can we respond to some of the concerns of the banks?’

“Clearly they can’t neglect their role as supervisors from a safety-and-soundness standpoint,” Forte added, although no one suggests they are doing so.

The Federal Reserve and FDIC exams are the same in substance, all bankers interviewed said.

Indeed, the FDIC doesn’t consider the recent conversions a concern, mostly because it’s confident all federal bank regulators conduct sound examinations.

“These procedures ensure risks to the Deposit Insurance Fund [the fund through which the FDIC insures bank deposits up to $100,000] are identified in a timely fashion regardless of whether a bank is supervised or examined by the Office of Thrift Supervision, the Office of the Comptroller of the Currency, the Federal Reserve or the FDIC,” said Franklin Gray, chief of the Risk Management and Applications Section at the FDIC’s headquarters in Washington, D.C. “Therefore, we are generally not concerned if an insured bank converts from a state charter to a national charter, from a state charter to a thrift charter or from state nonmember status to Fed member status.”

Further, he noted, the number of those switching isn’t huge. FDIC-supervised banks represented 57 percent of more than 8,000 insured institutions nationwide in 2000 and 60 percent today. The FRB supervised 10 percent of insured institutions in 2000 and the number has risen just slightly since then.

The OCC and OTS regulate the approximately 50 Massachusetts banks that have national charters.

‘Wonderfully Supportive’
The four community banks that recently changed regulators cited their primary motivators as either communication problems or concerns about potential conflicting roles that the FDIC has as both a bank examiner and insurer.

“My compliance officer would tell you how wonderfully supportive [the Federal Reserve] is. If she has a question as minor as ‘is the font size on this disclaimer big enough?’ to something much bigger Â… they’re here to help,” said Marblehead Savings Bank President and Chief Executive Officer Julie Livingston.

Livingston added that she has “tremendous admiration” for both Sheila Bair, the new chairman of the FDIC’s board, and Thomas Curry, the former Massachusetts bank commissioner who now directs the agency, saying the agency’s insurance arm is very helpful and communicative about fraud alerts.

But she’s not the only one to admire the Fed’s relative accessibility. Several bank chief executive officers said that when the FDIC moved its Northeast headquarters from Boston to New York in 2002, communication suffered.

“Several years back, the FDIC pulled up their stakes in Boston, and Boston became a sub-regional office. Really a branch. That was felt in a variety of ways,” said Northampton Cooperative President and Chief Executive Officer Bill Stapleton.

Stapleton said after that happened, he got the sense that local FDIC personnel “are more interested in what New York thinks than in the experience of the small community banks. That’s unlike in Boston, where the people at the Federal Reserve are Â… easy to get to.”

The FDIC’s Gray, however, said his agency maintains four Massachusetts offices, including a fully staffed area office in Braintree.

Bank of Easton’s Caron said even though his bank is small, “I feel like we have a true resource” in the Fed. “We can pick up the phone, ask for clarification on regulations and get call-backs,” he noted. “And there is no hesitation in offering an opinion ahead of time on how they’d handle something.”

But that doesn’t make bank examinations conducted by the Fed any easier.

“Examinations are every bit as intense and thorough as [the FDIC’s] and follow similar areas of focus. The difference is Â… the local connection and the absence of the ‘gotcha’ approach,” according to Caron.

One banker who requested anonymity said he’d experienced similar problems before deciding it was time to switch.

The banker recalled the early 1990s, when, he said, the Boston FDIC office was led by regulators whose main job before coming to Boston had been dealing with the savings-and-loan crisis and associated financial scandal in Texas, where the crisis hit hardest.

He said it appears they developed an adversarial mindset in the process, adding, “I don’t know that the mindset in the Boston office ever changed.”

Stapleton said concerns that his bank’s FDIC insurance premium was driven by the institution’s results on the exam issued by that same agency drove him to consider the switch.

“It seems to me there is an inherent conflict of interest, a substantial conflict, for the examiner to be the one that sets the rates,” he said.

Livingston said her predecessor, Edward H. Cowden, had the same concern.

“I know he felt that because they are the insurer, their findings are suspect,” she said.

Gray confirmed that a bank’s assessment rates do increase if its financial condition deteriorates. The rates range from 5 basis points per $100 in deposits (roughly 5 cents for every $100) for the best-rated banks to 43 basis points, per $100, for the worst.

Gray said his agency does not monitor which or how many banks are changing regulators – either in Massachusetts or elsewhere – because, as he noted earlier, the numbers aren’t compelling enough and because it’s confident all the regulators have good examination procedures in place.

The FDIC does, however, continue to monitor and update examination processes, he said, “to ensure that institutions are supervised in a fair, objective and professional manner.”