UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES AND EXCHANGE ACT OF 1934 For the Fiscal Year Ended September 30, 2019 ☐ 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 000-50924 BEACON ROOFING SUPPLY, INC. (Exact name of registrant as specified in its charter) Title of each class of each exchang ...