Nippon Steel offered to give the U.S. government a veto over any reduction in U.S. Steel's production capacity in a proposal that marks a last-ditch effort to win President Joe Biden’s approval for its takeover of the iconic American company, according to a person familiar with the matter. Shares of U.S. Steel surged by the most in a year.

The proposal is aimed at addressing concerns raised by the Committee on Foreign Investment in the U.S. (CFIUS), which said last week that the Japanese company’s takeover of U.S. Steel would lead to a decline in American steel output, said the person who asked not to be named because the information is private. The Washington Post reported on the proposal earlier.

Shares of U.S. Steel rose as much as 14% Tuesday in New York after the report, the biggest intraday jump since December 2023. The shares were trading at $34.19 as of 3:59 p.m. in New York, still well below Nippon Steel’s $55-a-share offer.