By Arathy Somasekhar

HOUSTON, March 26 (Reuters) - Activist investor Elliott

Investment Management has accepted the performance improvement

plan that U.S. oil refiner Phillips 66 laid out to boost

shareholder returns and share price, Chief Executive Mark

Lashier said in an interview on Tuesday.

"They've bought into our plans that we already had in

place," the CEO of one of the largest U.S. oil refiners said in

a briefing at its Houston headquarters.

Elliott sent a letter to the company's board last fall,

disclosing a $1 billion stake in the company, and calling for

additions to its board of directors and a focus on improving its

oil refining business.

Since the activist firm publicly disclosed its

recommendations, Phillips 66 shares have climbed 32%, to $156.37

per share, compared to a 15% increase in the S&P 500 Index.

"Elliott sees the progress. I think they've done quite

well as any investor has that entered the shares over the last

couple of years," he said.

Last month, Phillips 66 appointed Robert Pease, a veteran

refining executive as a director, and said it was looking to add

a second candidate to the 14-person board. Elliott had urged the

company last fall to add directors with refining experience that

could address underperformance in refining and speed up

cost-cutting efforts.

The oil refiner and pipeline operator's performance

improved in 2023's

fourth quarter

with higher margin capture in refining and gains by its

pipeline unit after a two-year period in which the company's

overall earnings lagged rivals.

(Reporting by Arathy Somasekhar)