Irvine-based Opus Bank will open new banking offices in Rancho Santa Margarita and San Rafael in the third quarter.

Opus is the largest bank based in Orange County, with about $3 billion in assets.

The bank had $2.3 billion in loans and $2.1 billion in deposits at the end of March.

The Rancho Santa Margarita office is Opus’ 10th location here, and the office in San Rafael is the second in the Bay Area.

The bank’s growing presence in the Bay Area is expected to “further strengthen through the previously announced acquisition of four banking offices from California Bank & Trust, which includes a banking office in Pleasant Hill,” Opus Chief Executive Stephen Gordon said.

Opus currently has 52 banking offices, with 30 in California and the rest in the Seattle region.