NEW YORK, Oct 15 (Reuters) - Pfizer appointed a former

chief executive officer at Vanguard, the drug giant's biggest

investor, to its board on Tuesday as it faces pressure from

activist hedge fund Starboard Value.

Mortimer "Tim" Buckley served as Vanguard's chairman and

chief executive until this year when he announced his

retirement. Buckley is 55.

Vanguard, one of the world's biggest asset managers, is

Pfizer's ( PFE ) largest shareholder, owning nearly 9% of the company's

stock, according to a regulatory filing.

Buckley's appointment was announced one day before Pfizer

and Starboard Value are scheduled to meet, giving the hedge

fund, which has built a $1 billion position, a chance to discuss

the company's strategy and its stock price.

Starboard has not publicly detailed its concerns about

Pfizer but people familiar with its thinking said the hedge fund

is concerned about the stock price and spate of mergers and

acquisitions. A spokesman for the hedge fund had no comment on

the board news.

Pfizer, which has a market capitalization of $165 billion,

said it began its search for a new board member in May. It named

Buckley days after Starboard's campaign at the drugs giant

became public.

Pfizer delivered the world's first Covid-19 vaccine but its

stock price has lost nearly half of its value since 2021 when

demand for the vaccine was high.

The standoff between the company and hedge fund took an

unusual turn last week. Two former Pfizer executives had

indicated they were working with Starboard to press for changes

at Pfizer but then reversed course and said they supported the

company's current CEO, Albert Bourla.

At Pfizer, Buckley will join the governance and

sustainability committee and the audit committee.

Since Bourla became CEO in 2019, six new directors have been

named to the board.

Buckley joined Vanguard 33 years ago as founder John Bogle's

research assistant and held top roles before being named CEO in

2018. Salim Ramji took over as Vanguard CEO in July, the company

said in a release.