Bank of Napa has been negotiating with Bank of Marin for several months, according to Kelly Solomon, CEO of Napa-based Coast Landscape Management Co. and a Bank of Napa board member for about five years. Bank of Marin on July 31 announced plans to acquire Bank of Napa in a stock deal valued at $51 million.

“We are a customer and were a customer” of the bank, Solomon said. She has been CEO of Coast Landscape for 17 years, and was a co-founder.

The acquisition, approved by boards of directors of both banks, is expected to close by the fourth quarter after approval from regulators and shareholders. The federal Office of the Comptroller of the Currency, a bureau within the U.S. Dept. of the Treasury, must approve the deal.

“The board was extremely happy with the results of our proposed transaction,” Solomon said. About two years ago, Bank of Napa added a branch in efforts to grow, as well as looking at possible mergers. Bank of Marin already had one branch in Napa. All three branches will remain open if the acquisition is approved, Solomon said.

No other local bank has significant presence in Napa, a city of 80,000 population, she said. “We are it. This opportunity will benefit our community as well as stockholders,” Solomon said. “Directors are extremely excited about this growth opportunity. We are very comfortable with this proposed merger.”

She has respect for Bank of Marin’s CEO Russ Colombo, who engineered the deal. “He is smart enough to know not to ruin the culture of what he is buying,” Solomon said. She expects most Bank of Napa employees to remain with Bank of Marin.

Bank of Napa branches will be rebranded as Bank of Marin. Solomon sees no problem with the branch shift. “We are a relationship bank,” she said. “As long as faces stay the same, I don’t see that the brand will matter. People will bank with people they are comfortable with no matter what the sign says out front.”

“This acquisition grows the Bank of Marin franchise by increasing our presence in Napa County, expanding our team of local, experienced bankers and adding quality commercial banking and deposit relationships,” said Colombo, president and CEO of Bank of Marin, in a statement. “Post-closing, our bank will be ranked first in deposit market share among community banks in the market.”

Bank of Napa has two branch offices in Napa. As of the end of the second quarter on June 30, the bank had $246 million in assets, deposits of $218 million and a loan portfolio of $139 million. Novato-based Bank of Marin had $2.1 billion in assets, deposits of $1.8 billion and loans totaling $1.5 billion.

At the close of the deal, Bank of Marin would have $2.4 billion in assets and 22 branches in five counties: Marin, Sonoma, Napa, Alameda and San Francisco.

Bank of Marin first came to Napa Valley in February 2011 with the Federal Deposit Insurance Corp.-assisted acquisition of Napa’s Charter Oak Bank. In 2013 the bank acquired Bank of Alameda, which had four branches.

Customers of Bank of Napa will have access to “expanded product line and larger lending limits via the acquisition, said its president and CEO, Tom LeMasters. “For our shareholders, it’s the opportunity to join one of the premier community banks in the Bay Area,” LeMasters said in a statement.

In the acquisition deal, each Bank of Napa share (OTCQB: BNNP) will be exchanged for 0.307 shares of Bank of Marin Bancorp (Nasdaq: BMRC) common stock. The estimated deal value was based on the $65.95 price for Bank of Marin shares at the close of trading Friday. The stock closed at $65.75 at the end of the Tuesday session.

Bank of Marin plans to add to its board one from Bank of Napa’s board.

Bank of Napa opened in 2006. Bank of Marin started in 1989.

“Since its founding as a community bank, and under the leadership of President Tom LeMasters, the Bank of Napa has earned its way on the list of Top 200 Healthiest Banks in the U.S. for two consecutive years. This collaboration between two A+ rated industry leaders will ultimately increase the community banking presence in Napa County, and provides benefits to our local businesses,” said Travis Stanley, president and CEO, Napa Chamber of Commerce. “This is a joint venture between two premier Bay Area community banks that will result in new available product lines and larger lending limits to go along with the stellar level of service we’ve grown to expect from Bank of Napa.”

James Dunn covers technology, biotech, law, the food industry, and banking and finance. Reach him at: james.dunn@busjrnl.com or 707-521-4257. Cynthia Sweeney and Jeff Quackenbush contributed to this report.