Shares of U.S. Steel dipped after a Nippon Steel executive told the Japanese Nikkei newspaper that its planned takeover of the company required "a degree of management freedom" to go ahead, even as sources told Reuters a deal with the U.S. government to greenlight the tie-up was effectively done. "Without a degree of management freedom, it may not be possible to reach an agreement with the U.S. government," the executive said, according to the newspaper, sending shares of the iconic U.S.