Canada-based Hydro One Limited says it will buy Spokane, Wash.-based Avista Corp. for C$67 ($53) per share in a C$6.7 billion ($5.3 billion) all-cash transaction.

The combined entity will serve more than two million retail and industrial customers and hold assets throughout North America, including Ontario, Washington, Oregon, Idaho, Montana and Alaska.

The companies say that over time, non-headcount efficiencies will be realized through collaboration and sharing of best practices on IT, innovation and supply chain purchasing. No workforce reductions are anticipated as a result of this transaction for either Avista or Hydro One.

Avista will maintain its existing corporate headquarters in Spokane and will continue to operate as a standalone utility in Washington, Oregon, Idaho, Montana and Alaska. Its management team and employees will remain in place and it will operate with its own Board of Directors. The combined company's headquarters will be based in Toronto.

The transaction was unanimously approved by the Boards of Directors of both companies and is expected to close in the second half of 2018. The deal is subject to Avista common shareholder approval and certain regulatory and government approvals and clearances, including approval by the Washington Utilities and Transportation Commission, the Public Utility Commission of Oregon, the Idaho Public Utilities Commission, the Regulatory Commission of Alaska, the Public Service Commission of the State of Montana, the U.S. Federal Energy Regulatory Commission, clearance by the Committee on Foreign Investment in the United States and compliance with applicable requirements under the U.S. Hart-Scott-Rodino Antitrust Improvements Act of 1976, as amended, and the satisfaction of customary closing conditions.

Hydro One is Ontario's largest electricity transmission and distribution provider with more than 1.3 million customers, C$25 billion in assets and annual revenues of more than C$6.5 billion. The company manages 30,000 circuit kilometers of high-voltage transmission and 123,000 circuit kilometers of primary distribution networks.

Avista Corp. produces, transmits and distributes electricity. Its utility operating division provides electric service to 379,000 customers and natural gas to 342,000 customers. Its service territory covers 30,000 square miles in eastern Washington, northern Idaho and parts of southern and eastern Oregon, with a population of 1.6 million. Alaska Energy and Resources Co. is an Avista subsidiary that provides retail electric service in the city and borough of Juneau, Alaska, through Alaska Electric Light and Power Company.