Pacific Premier Bancorp Inc. of Irvine announced it has agreed to acquire L.A.-based Grandpoint Capital Inc., the holding company of Grandpoint Bank, in a deal valued at about $641.2 million.

“The expansion of our organization remains a key focus of our long-term strategic plan as we build Pacific Premier into the leading commercial bank headquartered in Southern California,” said Steven Gardner, Pacific Premier’s president and chief executive officer.

The all-stock transaction, on a per-share basis, has a value of about $18.57 per share based on Pacific Premier’s common stock closing price of $39.10 on Feb. 9. Once the deal closes, Grandpoint stock holders will have the right to receive 0.4750 of a share of Pacific Premier common stock for each share of Grandpoint common stock they own. Existing Pacific Premier shareholders will own roughly 75 percent of the outstanding shares of the merged company and Grandpoint shareholders are expected to own about 25 percent.

Once the acquisition closes, expected in the third quarter, pending approvals, Premier will have about $11.7 billion in total assets on a pro forma basis.

Pacific Premier Bancorp is the holding company for Pacific Premier Bank, a business bank, with about $8 billion in assets and 33 branches. Grandpoint Bank has 14 regional offices in Southern California, Arizona, Vancouver and Washington and $2.3 billion in total assets.