BNC Financial Group, the holding company for The Bank of New Canaan and The Bank of Fairfield, will expand its footprint in Fairfield County with the purchase of The Wilton Bank.

The acquisition, at about $5 million, will add about $75 million to BNC Financial's balance sheet, bringing total assets to $700 million.

BNC Financial currently has five branches and one loan production office.

Stockholders of The Wilton Bank will receive $13.50 a share in cash.

BNC was part of a bidding process, said Peyton R. Patterson, president and CEO.

"They approached us via their investment banker," she said. "It will be business as usual at The Wilton Bank until the closing at the latter part of 2013. Our products and services will be on one platform in the first quarter of 2014."

Charles Howell, The Wilton Bank CEO, president and treasurer, will resign at the closing, Patterson said.

Commenting that it is premature to discuss the fate of The Wilton Bank's employees, she said some will remain in place while others will be invited to apply for positions within the BNC family.

The Wilton Bank and BNC have a like-minded community banking philosophy, and the deal will enhance offerings to The Wilton Bank customers, Howell said.

The Wilton Bank was hit hard by the recession and never fully recovered, said John Carusone, president of the Bank Analysis Center in Hartford.

"The Wilton Bank has struggled in the past few years under the heavy burden of non-performing loans left over from the recession," he said. "This is an appropriate exit strategy for The Bank of Wilton shareholders."

The transaction was unanimously approved by the boards of directors of both banks. The closing is subject to approval by The Wilton Bank's stockholders and customary regulatory approvals.

BNC plans to establish a Wilton Advisory Board to promote continuity and maintain the legacy that The Wilton Bank has established in the community, according to Patterson.

BNC, traded as an over-the-counter stock under the ticker symbol "BNFI," saw its share price fall 25 cents, or 1.2 percent, to $21 on Friday. The Wilton Bank traded as an OTC stock under the ticker symbol "WIBW," surged $2.71, or 26 percent, to $13.20.