Everett-based Frontier Bank was closed Friday evening by the Washington Department of Financial Institutions, which appointed the Federal Deposit Insurance Corporation (FDIC) as receiver.

The 51 branches of Frontier Bank will reopen during normal business hours as locations of Union Bank, N.A. under a purchase and assumption agreement arranged by FDIC. More detail on the transaction is available on the FDIC website.

As of December 31, 2009, Frontier had approximately $3.50 billion in total assets and $3.13 billion in total deposits. In addition to assuming all of the deposits, Union Bank agreed to purchase essentially all of the failed bank's assets. It entered into a loss-share transaction on $3.04 billion of Frontier Bank's assets.

According to federal regulators, this loss-share transaction is projected to maximize returns on the assets covered by keeping them in the private sector. FDIC estimates that the cost to the Deposit Insurance Fund will be $1.37 billion and said this acquisition of all the deposits was the "least costly" resolution for the FDIC's DIF compared to all alternatives.

All shares of Frontier Bank were owned by its holding company, Frontier Financial Corp., which was not included in the closing of the bank or the resulting receivership.

Frontier Bank is the 64th FDIC-insured institution to fail in the nation this year, and the sixth in Washington.