2020 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Fiscal Year Ended December 31, 2020 Or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to . Commission file number 1-16811 United States Steel Corporation (Exact name of registrant as specified in its charter) Delaware 25-1897152 (State of Incor ...

United States Steel Corporation (NYSE:X) Q4 2020 Earnings Conference Call January 29, 2021 8:30 AM ET Company Participants Kevin Lewis - Vice President-Investor Relations and Corporate FP&A David Burritt - President and Chief Executive Officer Christie Breves - Senior Vice President and Chief Financial Officer Rich Fruehauf - Senior Vice President and Chief Strategy and Development Officer Conference Call Participants Chris Terry - Deutsche Bank Seth Rosenfeld - Exane BNP David Gagliano - BMO Capital Market ...

United States Steel Corporation (NYSE:X) Q3 2020 Earnings Conference Call October 30, 2020 8:30 AM ET Company Participants Kevin Lewis – Vice President-Investor Relations and Corporate FP&A Dave Burritt – President and Chief Executive Officer Christie Breves – Senior Vice President and Chief Financial Officer Rich Fruehauf – Senior Vice President and Chief Strategy and Development Officer Conference Call Participants Karl Blunden – Goldman Sachs Seth Rosenfeld – Exane BNP Chris Terry – Deutsche Bank David G ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended September 30, 2020 Or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to . United States Steel Corporation (Exact name of registrant as specified in its charter) (State or other jurisdiction of incorporation) (Commission Fil ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the Quarterly Period Ended June 30, 2020 Or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to . United States Steel Corporation (Exact name of registrant as specified in its charter) Delaware 1-16811 25-1897152 (State or other jurisdiction of incorpo ...