With approvals already received from the companies’ boards of directors and concerned regulators, the $506m merger proposal was originally inked in September 2012.
The merged entity will have nearly $7.2bn in assets with a network of 150 branches across Washington and Oregon, the acquirer said.
As per the terms of the agreement, West Coast shareholders will own nearly 24% of the common stock of the combined company and will be offered consideration valued at approximately $23.10 per share, the bank said.
Further, West Coast common stock share will be converted into the right to receive merger consideration consisting of shares of Columbia common stock or cash.
Keefe, Bruyette & Woods offered financial advice to Columbia Banking, while Graham & Dunn served as legal counsel to the bank.
Sandler O’Neill + Partners acted as a financial advisor for West Coast, and Wachtell, Lipton, Rosen & Katz worked as legal counsel.
Columbia Banking System is a Washington state-chartered full-service commercial bank, while West Coast Bancorp is a publicly held, Northwest bank holding company with $2.4bn in assets.