U.S. authorities extended a deadline imposed on Japan's Nippon Steel Corp. and United States Steel Corp. to abandon their merger plan to June 18, the companies said Sunday, a move that came as they fight to advance the deal in courts.U.S. President Joe Biden issued an order on Jan. 3 to block the $14.1 billion takeover of U.S. Steel by the Japanese company on national security grounds and urged the companies to take all steps necessary to "fully and permanently" abandon the deal within 30 days.However, the order also stated the period can be extended by the Committee on Foreign Investment i…READ FULL ARTICLE