UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Title of each class Trading Symbol Name of each exchange on which registered American Depositary Shares, each representing ten ordinary shares, par value US$0.001 per share ANTE The Nasdaq Stock Market LLC (The Nasdaq Capital Market) Ordinary shares, par value US$0.001 per share* The Nasdaq Stock Market LLC (The Nasdaq Capital FORM 20-F REGISTRATION STATEMENT PURSUANT TO SECTION 12(b) or (g) OF THE SECURITIES EXCHANGE ACT OF 1934 OR ANN ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington D.C. 20549 FORM 20-F ¨ REGISTRATION STATEMENT PURSUANT TO SECTION 12(b) OR (g) OF THE SECURITIES EXCHANGE ACT OF 1934 OR 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 OR ¨ SHELL COMPANY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of e ...