The holding companies of Grandpoint Bank and the National Bank of California said they have signed a definitive merger agreement in which Grandpoint Capital will acquire NCal Bancorp.

National Bank of California will become a wholly owned subsidiary of Grandpoint Capital, pending shareholder and regulatory approvals, the companies said late Monday. The deal is expected to close in the fourth quarter.

National Bank of California was founded in 1982 and operates five branches in Los Angeles and Orange counties. As of March 31, it had total assets of nearly $341 million. Its shares on the Over-the-Counter Bulletin Board traded at $2.85 at midday Tuesday, giving it a market cap of $6.73 million.

All outstanding preferred shares of NCal Bancorp issued to the Department of the Treasury shall be redeemed at a stated value of $10.5 million. How much the other shareholders will receive is undetermined; they are to get money at the closing and an additional payment in two years that is based on a formula tied partly to loan recoveries.

However, the bank company said that had the transaction closed on May 31, Ncal shareholders would have received $1.45 a share, or $3.37 million, plus $1.70 a share, or $3.96 million, based on the formula.

“This is another outstanding opportunity for Grandpoint to partner with a bank that has a similar business focus and a well established banking office network that complements our own,” said Grandpoint Chairman Don M. Griffith in a statement, adding that the current management team is expected to stay.

This is Grandpoint’s third announced acquisition this year. In January it said it would buy California Community Bank, an Escondido institution with four branches, and in February announced its intention to buy Phoenix’s Bank Capital Corp., the parent of Biltmore Bank of Arizona.