UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K [X] Annual report pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 For the fiscal year ended December 31, 2018, 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 001-32663 CLEAR CHANNEL OUTDOOR HOLDINGS, INC. (Exact name of registrant as specified in its charter) (State or other juris ...