Sept 25 (Reuters) - U.S. Steel said on Wednesday

an arbitration board had ruled in favor of Nippon Steel's ( NISTF )

$14.9 billion buyout of the company, but that the

United Steelworkers union disagreed with the decision.

The board, jointly selected by the company and the union to

settle disputes, ruled that U.S. Steel had satisfied each of the

conditions of the successorship clause in its basic labor

agreement with the USW.

"The arbitrators accepted at face-value Nippon Steel's ( NISTF )

statement that it would assume the Basic Labor Agreement," USW

said.

The union said the decision did not change its opposition to

the deal.

"We remain focused on forging a productive relationship with

the USW, which includes fulfilling our commitments that go far

beyond what is currently required in the existing BLA," Nippon

Steel ( NISTF ) said in a statement.

The deal has faced political opposition since it was signed

last December. Democratic presidential candidate Kamala Harris

and her Republican challenger Donald Trump have supported U.S.

Steel remaining American-owned.

Nippon Steel ( NISTF ) had paid a hefty premium to clinch the deal for

U.S. Steel on a bet that it could benefit from U.S. President

Joe Biden's infrastructure spending bill.

Earlier this month, U.S. Steel warned that a failure to

conclude the deal would put thousands of U.S. union jobs at risk

and signaled that it would close some steel mills and

potentially move its headquarters out of the politically

important state of Pennsylvania.

Nippon Steel ( NISTF ) President Tadashi Imai told reporters on

Thursday in Tokyo that the U.S. Committee on Foreign Investment

had extended its review of the deal until the end of December,

or until after the Nov. 5 presidential elections.

The extension was not reason to be overly optimistic and the

company continued to seek dialog with the USW as it still aimed

to close the deal by the end of December, Imai said.