The $1.35 billion sale of Frontier Communications’ operations in Washington, Oregon, Idaho and Montana to a group of investors calling the new company Ziply Fiber was expected to be completed Friday.

Kirkland-based Ziply Fiber, which will serve nearly 500,000 residential and commercial customers, plans to immediately start spending $500 million on service improvements to its internet, phone and TV offerings.

“We see significant opportunity to improve the quality of the networks for our Northwest communities,” Harold Zeitz, Ziply Fiber’s CEO, said in a statement.

Ziply’s top brass include former executives of AT&T, CenturyLink and Wave Broadband.

Frontier announced plans to sell its Northwest assets last May as part of its debt-reduction efforts.