This story has been updated from a previous version.

Two banks controlled by Downey entrepreneur Alex Meruelo are set to formally join forces.

Irvine’s Commercial Bank of California will buy Brentwood’s National Bank of California which Meruelo recapitalized in December.

In addition to its Brentwood headquarters, National Bank has branches in Sherman Oaks, Beverly Grove and Costa Mesa. Commercial Bank has one branch each in Irvine and Brea.

Both banks said all branches would remain open after the acquisition closes in the first quarter of 2016.

Commercial Bank Chief Executive Ash Patel joined the bank in October 2013 and moved its headquarters to Irvine about a year later. Patel became chairman of National Bank when Meruelo, the founder of the La Pizza Loca restaurant chain, made his investment.

National Bank had about $372 million in assets and $336 million in deposits as of June 30, placing No. 27 on the Business Journal’s most recent ranking of Los Angeles County banks. Commercial Bank had about $320 million in assets and $274 million in deposits at the same time, making it the fourteenth-largest in Orange County.