PBB Bancorp, the parent company of downtown L.A.’s Premier Business Bank, announced late Thursday that it has entered into negotiations to merge with Big Bear Lake’s First Mountain Bank.

The two banks expect a merger agreement to be signed by the middle of this month, which would be the latest in a series of bank mergers that have swept the L.A. area in recent years.

“Community banking is the core focus of Premier Business Bank,” PBB Chief Executive John Polen said in a press release. “I believe that completion of our merger will provide First Mountain Bank more services to offer to its customers, more support for its community and more opportunities for its employees.”

“We are pleased with the progress of the merger process and the opportunity to combine with Premier Business Bank,” First Mountain Chairman Vince Smith said in the press release. “We believe they share our long standing commitment to serve our customers and support our communities.”

Both banks are relatively small and could see a merger as a way to share compliance costs, which have been grown in the wake of tightened bank regulations. That’s been a factor in several recent small bank deals, including the sale late last year of Covina’s Simplicity Bancorp to Seattle thrift HomeStreet Inc.

Premier Business Bank, which had $239 million in assets as of March 31, has branches in downtown Los Angeles and Rolling Hills Estates and a loan office in Torrance. First Mountain Bank, with $146 million in assets, has branches in Big Bear Lake, Running Springs and Lucerne Valley.