After receiving two bids to acquire it in the past month, U.S. Steel has told its shareholders that it is in the process of reviewing multiple offers for the storied company and symbol of American industrialization. U.S. Steel rejected a $7.3 billion buyout proposal from rival Cleveland-Cliffs two weeks ago. Following that, industrial conglomerate Esmark offered $7.8 billion for the Pittsburgh steelmaker, whose shares soared more than 30% on speculation that a deal was imminent. In a letter to shareholders Tuesday, U.S. Steel said it had entered into confidentiality agreements with “numerous” third parties and was starting to share due diligence information with suitors.