Nov 1 (Reuters) - Prominent proxy advisory firm

Institutional Shareholder Services on Friday recommended

Frontier Communications shareholders abstain from

voting on Verizon's $20 billion takeover bid and instead

support the adjournment proposal.

Shareholders must decide whether a sale to Verizon, which

likely would not close for at least another year, represents a

better risk-adjusted alternative to the company's standalone

option, the proxy advisory firm said in a report.

"Given the possibility of substantially more value down the

line, and the lack of urgency to approve a transaction ... it

seems reasonable for shareholders to exercise the optionality of

abstaining for the time being," ISS said.

Verizon said in September it would buy Frontier at an offer

price of $38.50 per share, as the U.S. telecom giant looks to

build its fiber subscriber base and better compete with rivals

such as AT&T ( T ).

The takeover, however, has faced opposition from some

Frontier shareholders. Reuters first reported last month that

some of the fiber-optic internet provider's largest shareholders

were concerned about the deal.

Glendon Capital Management, which owns nearly 10% of

Frontier, said last month it had decided to vote against the

deal at the current price, as it "significantly undervalues"

Frontier's assets and earnings trajectory.

ISS said the firm finds it unlikely that Verizon would

"dramatically raise its bid for Frontier at this stage."

Last week, Frontier urged its shareholders to vote for the

proposal, saying that it had reviewed interest from other

potential buyers and found Verizon's proposal as the most

favorable option.

The offer was "highly attractive" and creates significant

value for stockholders, it had then said.