Irvine-based based First Foundation Bank will pay $16 million in cash and stock for Desert Commercial Bank in El Centro.

An additional $4 million could be paid if Desert Commercial’s loan portfolio meets certain future benchmarks.

First Foundation is the fifth-largest savings and loan based in Orange County based on deposits here, according to the Business Journal’s list earlier this year. The acquisition is likely to boost it a couple of notches.

Desert has assets of $153 million, and offices in Palm Desert and El Centro.

First Foundation Inc. has $456 million in assets and offices here and in La Quinta, Pasadena and San Diego.

Chief Executive Scott F. Kavanaugh said First Foundation’s acquisition marked “an excellent opportunity to continue to expand its market presence within the greater California market. We are particularly excited to strengthen our investment in the Coachella and Imperial valleys."

The deal is expected to be final before the end of 2011.

First Foundation’s buy follows a deal last month for Fullerton Community Bank to be sold to Opus Bank, which has its executive headquarters in Irvine.

Fullerton Community is the largest savings and loan in Orange County based on deposits.

Opus has its on-the-books headquarters in Redondo Beach.