21Vianet Group, Inc.

Beneficial ownership report for a holder of more than 5% (Schedule 13D) (amendment)

Beneficial ownership report for a holder of more than 5% (Schedule 13D) (amendment)

Report of foreign private issuer pursuant to Rule 13a-16 or 15d-16 under the Securities Exchange Act of 1934

Beneficial ownership report for a holder of more than 5% (Schedule 13D)

Report of foreign private issuer pursuant to Rule 13a-16 or 15d-16 under the Securities Exchange Act of 1934

Beneficial ownership report for a passive holder of more than 5% (Schedule 13G) (amendment)

Report of foreign private issuer pursuant to Rule 13a-16 or 15d-16 under the Securities Exchange Act of 1934

Beneficial ownership report for a holder of more than 5% (Schedule 13D) (amendment)

Beneficial ownership report for a holder of more than 5% (Schedule 13D) (amendment)

Report of foreign private issuer pursuant to Rule 13a-16 or 15d-16 under the Securities Exchange Act of 1934

Report of foreign private issuer pursuant to Rule 13a-16 or 15d-16 under the Securities Exchange Act of 1934

Registration statement / Annual report / Transition report for Foreign Private Issuers

Report of foreign private issuer pursuant to Rule 13a-16 or 15d-16 under the Securities Exchange Act of 1934

Report of foreign private issuer pursuant to Rule 13a-16 or 15d-16 under the Securities Exchange Act of 1934

Report of foreign private issuer pursuant to Rule 13a-16 or 15d-16 under the Securities Exchange Act of 1934

Report of foreign private issuer pursuant to Rule 13a-16 or 15d-16 under the Securities Exchange Act of 1934

Report of foreign private issuer pursuant to Rule 13a-16 or 15d-16 under the Securities Exchange Act of 1934

Report of foreign private issuer pursuant to Rule 13a-16 or 15d-16 under the Securities Exchange Act of 1934

Report of foreign private issuer pursuant to Rule 13a-16 or 15d-16 under the Securities Exchange Act of 1934

Report of foreign private issuer pursuant to Rule 13a-16 or 15d-16 under the Securities Exchange Act of 1934

Report of foreign private issuer pursuant to Rule 13a-16 or 15d-16 under the Securities Exchange Act of 1934

Report of foreign private issuer pursuant to Rule 13a-16 or 15d-16 under the Securities Exchange Act of 1934

Report of foreign private issuer pursuant to Rule 13a-16 or 15d-16 under the Securities Exchange Act of 1934

Registration statement / Annual report / Transition report for Foreign Private Issuers

Report of foreign private issuer pursuant to Rule 13a-16 or 15d-16 under the Securities Exchange Act of 1934

Report of foreign private issuer pursuant to Rule 13a-16 or 15d-16 under the Securities Exchange Act of 1934

Report of foreign private issuer pursuant to Rule 13a-16 or 15d-16 under the Securities Exchange Act of 1934

Report of foreign private issuer pursuant to Rule 13a-16 or 15d-16 under the Securities Exchange Act of 1934

Registration statement under Securities Act of 1933 to be offered to employees pursuant to certain plans

Letter from the SEC

Correspondence with the SEC

Letter from the SEC

Correspondence with the SEC

Letter from the SEC

Registration statement / Annual report / Transition report for Foreign Private Issuers

Letter from the SEC

Registration statement / Annual report / Transition report for Foreign Private Issuers (amendment)

Correspondence with the SEC

Letter from the SEC

Correspondence with the SEC

Letter from the SEC

Correspondence with the SEC

Letter from the SEC

Correspondence with the SEC

Letter from the SEC

Registration statement / Annual report / Transition report for Foreign Private Issuers

Registration statement / Annual report / Transition report for Foreign Private Issuers

Prospectus Supplement for Primary Offering

Registration statement / Annual report / Transition report for Foreign Private Issuers

Registration statement under Securities Act of 1933 to be offered to employees pursuant to certain plans

Prospectus Supplement for Primary Offering

Prospectus Supplement for Primary Offering

No description available

No description available

Registration statement / Annual report / Transition report for Foreign Private Issuers

Registration statement / Annual report / Transition report for Foreign Private Issuers

Registration statement / Annual report / Transition report for Foreign Private Issuers

Registration statement under Securities Act of 1933 to be offered to employees pursuant to certain plans

Letter from the SEC

Correspondence with the SEC

Letter from the SEC

Correspondence with the SEC

Registration statement / Annual report / Transition report for Foreign Private Issuers

Registration statement / Annual report / Transition report for Foreign Private Issuers

Registration statement under Securities Act of 1933 to be offered to employees pursuant to certain plans

Registration statement / Annual report / Transition report for Foreign Private Issuers

Registration statement under Securities Act of 1933 to be offered to employees pursuant to certain plans

Registration statement / Annual report / Transition report for Foreign Private Issuers

Registration statement / Annual report / Transition report for Foreign Private Issuers (amendment)

Registration statement / Annual report / Transition report for Foreign Private Issuers

Registration statement under Securities Act of 1933 to be offered to employees pursuant to certain plans

Registration statement / Annual report / Transition report for Foreign Private Issuers

Registration statement under Securities Act of 1933 to be offered to employees pursuant to certain plans

Prospectus Supplement with Pricing Information

No description available

Free Writing Prospectus

Registration statement for securities of certain foreign private issuers (amendment)

Notice of Effectiveness

Notice of Effectiveness

Registration statement for securities of certain foreign private issuers (amendment)

Registration of Securities on Exchange

Registration statement for securities of certain foreign private issuers (amendment)

Registration statement under the Securities Act of 1933 for depositary shares evidenced by American depositary receipts

Chen David Lifeng

Shao Sean

ZHANG ZHIHUA

TAI KENNETH

Shao Sean

UENO Yoshihisa

Chen David Lifeng

Chen David Lifeng

Chen David Lifeng

Shao Sean

UENO Yoshihisa

Shao Sean

ZHANG ZHIHUA

WANG QIYU