Upwork(UPWK) - 2018 Q4 - Annual Report

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 _____________________________ FORM 10-K _____________________________ (Mark One) 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 001-38678 _____________________________ UPWORK INC. (Exact na ...