Shareholders of United States Steel will vote on Friday on a planned takeover of the company by a Japanese firm. This comes amid a labor union's opposition to the buyout.

US Steel and Nippon Steel announced in December that they had entered into an agreement that would enable the Japanese firm to acquire the US corporation in an all-cash transaction.

Both sides said at the time that the deal was "expected to close in the second or third quarter of calendar year 2024." They added that it was subject to approval by US Steel shareholders and regulators.

Nippon Steel said it would buy US Steel at 55 dollars per share and that the purchase price represented a 40 percent premium to the US company's closing stock price on December 15, 2023.

Two major US proxy advisory firms, which provide guidance to investors, have recommended that US Steel shareholders vote for the transaction.

But the United Steelworkers union, or USW, opposes the deal. Its negotiations with Nippon Steel have yet to be concluded.

The USW said on Tuesday that it had received a letter from Nippon Steel that contains some commitments. But the USW responded by reiterating that it opposes the acquisition plan. It described the letter as "another meaningless piece of paper."

In March, US President Joe Biden also indicated that he does not support the proposed takeover. Biden said that he wants US Steel to remain "domestically owned and operated."