1、Table of Contents UNITED STATESSECURITIES AND EXCHANGE COMMISSIONWASHINGTON,D.C.20549 FORM 20-F(Mark One)oREGISTRATION STATEMENT PURSUANT TO SECTION 12(b)OR 12(g)OF THE SECURITIES EXCHANGE ACT OF 1934 OR xANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d)OF THE SECURITIES EXCHANGE ACT OF 1934For the fisc
2、al year ended December 31,2019.OR oTRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d)OF THE SECURITIES EXCHANGE ACT OF 1934 OR oSHELL COMPANY REPORT PURSUANT TO SECTION 13 OR 15(d)OF THE SECURITIES EXCHANGE ACT OF 1934 Date of event requiring this shell company report.For the transition period from t
3、o Commission file number:001-35126 21Vianet Group,Inc.(Exact name of Registrant as specified in its charter)N/A(Translation of Registrants name into English)Cayman Islands(Jurisdiction of incorporation or organization)Guanjie Building Southeast 1st Floor,10#Jiuxianqiao East Road,Chaoyang DistrictBei
4、jing,100016The Peoples Republic of China(Address of principal executive offices)Ms.Sharon Xiao Liu,Chief Financial Officer21Vianet Group,Inc.Guanjie Building Southeast 1st Floor,10#Jiuxianqiao East Road,Chaoyang DistrictBeijing,100016The Peoples Republic of ChinaPhone:(86)10 8456-2121Facsimile:(86)1
5、0 8456-4234(Name,Telephone,E-mail and/or Facsimile number and Address of Company Contact Person)Securities registered or to be registered pursuant to Section 12(b)of the Act:Title of each class Trading Symbol Name of exchange on which registeredAmerican depositary shares,each representing six Class
6、A ordinary shares,parvalue US$0.00001 per share VNET NASDAQ Global Select Market Class A ordinary shares,par value US$0.00001 per share*Not for trading,but only in connection with the listing on the Nasdaq Global Select Market of the American depositary shares Securities registered or to be register