The $619 million Webster First Federal Credit Union, active in2011 with three Massachusetts mergers, is expanding its Bostonfootprint this month by taking over a fourth, the $20 millionFilene Federal Credit Union.

Members of Filene, whose employee base is tied to thenow-shuttered Filene retail chain once operated by credit unionpioneer Edward Filene, approved the merger with Webster First at ameeting Tuesday.

The NCUA had approved the transaction Jan. 25 with a similar OKreceived from the Massachusetts Share Insurance Corp. The merger,which had been under discussion for some months, becomes formallyeffective Saturday.

“We are grateful Filene management and members chose us based,we believe, on our financial strength – 18% capital and ROA of1.12,” said Michael Lussier, president/CEO of Webster First, headquarteredin Worcester. Lussier is also the current chairman of NAFCU.

The 1,700-member Boston credit union has maintained a steadycapital position but did lose $199,000 in 2010 and $510,000 in2011.

Filene's decision to merge, said Lussier, underscores the plightof many small credit unions “who realize the difficulty ofoperating in today's challenging regulatory environment and tryingto do business with narrowed margins.”

Lussier said there are no plans to scout further mergerpossibilities in Massachusetts. “But our eyes are always open,” hesaid.

Filene has one downtown Boston branch and is one of the state'soldest credit unions. The famed Filene Basement store closed inDecember after an earlier bankruptcy sale.

Since last July, Webster First has completed the mergers ofSaugus FCU, Winthrop FCU and Fitchburg FCU. The Filene addition wouldincrease branch penetration in the Boston area to five plus a sixthplanned in Hopkintown. Webster First has 17 branches statewide.

Asked about Webster First's interest in purchasing a savingsbank, along the lines of the $345 million GFA FCU in nearbyGardner, Lussier said, “Yes, but only if it fit our businessmodel.”

That milestone takeover of an ailing New Hampshire bank isexpected to take months to win FDIC, NCUA and state approval.

The ailing $82 million Monadnock Community Bank of Peterborough has been under a DORand sought out both bank and credit union buyers.

“I congratulate GFA's CEO for pursuing that kind oftransaction,” said Lussier. He also said he has no interest infollowing the path of a competitor, HarborOne of Brockton, inpursuing a charter switch to a mutual savings bank.