[21Vianet Group Forms a Special Committee to Review the Going-private Proposal BEIJING, China, April 16, 2015 (GLOBE NEWSWIRE) — 21Vianet Group, Inc. (Nasdaq:VNET) (“21Vianet” or the “Company”), a leading carrier-neutral Internet data center services provider in China, today announced that in response to the preliminary non-binding proposal dated June 10, 2015 (the “Proposal”) from Mr. Josh Sheng Chen, the Chairman] [FORM 6-K 21Vianet Group, Inc. M5, 1 Jiuxianqiao East Road, Chaoyang District Beijing 100016 The People’s Republic of China (86 10) 8456 2121 x ¨ Form 20-F ¨ ¨ 21Vianet Group, Inc. Sheng Chen Chairman and Chief Executive Officer 6-K 1 d947043d6k.htm FORM 6-K]

[21Vianet Group, Inc. Announces Receipt of Preliminary Non-Binding “Going Private” Proposal BEIJING, China, June 10, 2015 — 21Vianet Group, Inc. (Nasdaq: VNET) (“21Vianet” or the “Company”), a leading carrier-neutral internet data center services provider in China, announced that its Board of Directors (the “Board”) has received a non-binding proposal letter, dated June 10, 2015, from Mr. Josh Sheng Chen (“Mr.] [FORM 6-K 21Vianet Group, Inc. M5, 1 Jiuxianqiao East Road, Chaoyang District Beijing 100016 The People’s Republic of China (86 10) 8456 2121 x ¨ Form 20-F ¨ ¨ 21Vianet Group, Inc. Shang-Wen Hsiao Chief Financial Officer 6-K 1 d941588d6k.htm FORM 6-K]

[21Vianet Group Inc. Announces Change in Leadership Team BEIJING, June 10, 2015 – 21Vianet Group, Inc. (NASDAQ:VNET) (“21Vianet” or the “Company”), a leading carrier-neutral internet data center services provider in China, today announced that Mr. Frank Meng, the president of the Company, will be leaving the Company to pursue other opportunities, effective immediately. Mr. Josh Chen, Founder, Chairman and Chief] [FORM 6-K 21Vianet Group, Inc. M5, 1 Jiuxianqiao East Road, Chaoyang District Beijing 100016 The People’s Republic of China (86 10) 8456 2121 x ¨ Form 20-F ¨ ¨ 21Vianet Group, Inc. Shang-Wen Hsiao Chief Financial Officer 6-K 1 d941584d6k.htm FORM 6-K]

[21Vianet Group, Inc. Reports First Quarter 2015 Unaudited Financial Results 1Q15 Net Revenues Up 46.8% YOY to RMB860.1 Million 1Q15 Adjusted EBITDA Up 47.8% YOY to RMB166.9 Million Live Conference Call to be Held at 8:00 PM U.S. Eastern Time, May 26, 2015 BEIJING, May 26, 2015 (GLOBE NEWSWIRE) — 21Vianet Group, Inc. (Nasdaq: VNET) (“21Vianet” or the “Company”), a] [FORM 6-K 21Vianet Group, Inc. M5, 1 Jiuxianqiao East Road, Chaoyang District Beijing 100016 The People’s Republic of China (86 10) 8456 2121 x ¨ Form 20-F ¨ ¨ 21Vianet Group, Inc. Shang-Wen Hsiao Chief Financial Officer 6-K 1 d932952d6k.htm FORM 6-K]