(Reuters) - Frontier Communications shareholders have approved a $9.6 billion sale to Verizon, the company said on Wednesday, even as a number of large investors sought to get a higher price. Shareholders had until Wednesday to cast their votes on a deal that Verizon's CEO Hans Vestberg called a "strategic fit" that would allow the company to be more competitive in additional markets.

The deal will take 18 months to close.

Verizon will pay $38.50 a share for Frontier and absorb about $10 billion of the company's debt. When the deal was announced in September, it represented a 44% premium to Frontier's 90-day volume-weighted average share price.

A number of large shareholders last month, however, expressed concern about the price, arguing that Verizon should pay more and signaling they would vote against the deal.

Proxy advisory firms Institutional Shareholder Services and Glass Lewis urged Frontier investors to abstain, which would essentially be a vote against the deal, in order to have more time to consider options.

Verizon announced the deal almost a year after activist investment firm Jana Partners said it had built a position in Frontier and was calling on the third-largest U.S. fiber broadband provider to sell itself.

For Verizon the acquisition would help it compete better against rivals AT&T ( T ) and T-Mobile as they double down on unlimited plans and bundling options.

(This story has been refiled to remove an incorrect picture)