PacWest Bancorp said it will buy CapitalSource Inc for about $2.29 billion in cash and stock to expand its presence in Southern California.

CapitalSource shareholders will receive $2.47 in cash and 0.2837 shares of PacWest common stock for each share held.

The deal values CapitalSource at $11.68 per share, which represents a premium of 19 percent to CapitalSource's Monday closing price.

(Reporting by Avik Das in Bangalore)