SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 13G
(Rule 13d-102)

INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO RULES
13d-1 (b), (c) AND (d) AND AMENDMENTS THERETO FILED PURSUANT TO 13d-2

UNDER THE SECURITIES EXCHANGE ACT OF 1934
(Amendment No. 8)*

21Vianet Group, Inc.
(Name of Issuer)

Ordinary Shares, Par Value US$0.00001 Per Share
(Title of Class of Securities)

G91458 102
(CUSIP Number)

December 31, 2020
(Date of Event Which Requires Filing of this Statement)

Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

o Rule 13d-1(b)

o Rule 13d-1(c)

x Rule 13d-1(d)

*                 The remainder of this cover page shall be filled out for a reporting person’s initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed to be “filed” for the purpose of Section 18 of the Securities Exchange Act of 1934 (“Act”) or otherwise subject to the liabilities of that section of the Act but shall be subject to all other provisions of the Act (however, see the Notes).

1  Representing (i) 19,670,117 Class B ordinary shares held by Fast Horse Technology Limited; (ii) 12,187,875 Class B ordinary shares and 6,700,000 Class A ordinary shares held by Sunrise Corporate Holding Ltd.; (iii) 60,000 Class C ordinary shares, 769,486 Class B ordinary shares and four Class A ordinary shares held by Personal Group Limited; (iv) 3,894,737 Class A ordinary shares held by Beacon Capital Group Inc.; and (v) 1,479,666 Class A ordinary shares upon vesting of Mr. Chen’s restricted share units within 60 days as of December 31, 2020. Mr. Chen is the sole shareholder of Fast Horse Technology Limited, Sunrise Corporate Holding Ltd., Personal Group Limited and Beacon Capital Group Inc. and thus has the sole voting and dispositive power over the shares held by them. Holders of Class A ordinary shares, Class B ordinary shares and Class C ordinary shares have the same rights except for voting and conversion rights. Each Class A ordinary share is entitled to one vote, whereas (x) each Class B ordinary share is entitled to ten votes and is convertible into one Class A ordinary share at any time by the holder thereof and (y) each Class C ordinary share is entitled to one vote except for veto right on three corporate matters and is convertible into one Class A ordinary share at any time by the holder thereof. Class A ordinary shares are not convertible into Class B ordinary shares or Class C ordinary shares under any circumstances.

2  The beneficial ownership percentage is calculated based on 817,170,095 ordinary shares of the Issuer as a single class, being the sum of (i) 671,234,982 Class A ordinary shares (excluding treasury shares and Class A ordinary shares in the form of ADSs that are reserved for issuance upon the exercise of share incentive awards) outstanding as of December 31, 2020, (ii) 145,875,113 Class B ordinary shares issued and outstanding as of December 31, 2020, and (iii) 60,000 Class C ordinary shares issued and outstanding as of December 31, 2020. The voting power of the shares beneficially owned by the Reporting Person represented 15.5% of the aggregate voting power of the total outstanding ordinary shares of the Issuer.

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1  Representing 19,670,117 Class B ordinary shares that are convertible into the same number of Class A ordinary shares at any time at the option of the holder. Fast Horse Technology Limited is 100% owned by Mr. Sheng Chen.

2  The beneficial ownership percentage is calculated based on 817,170,095 ordinary shares of the Issuer as a single class, being the sum of (i) 671,234,982 Class A ordinary shares (excluding treasury shares and Class A ordinary shares in the form of ADSs that are reserved for issuance upon the exercise of share incentive awards) outstanding as of December 31, 2020, (ii) 145,875,113 Class B ordinary shares issued and outstanding as of December 31, 2020, and (iii) 60,000 Class C ordinary shares issued and outstanding as of December 31, 2020. The voting power of the shares beneficially owned by the Reporting Person represented 9.0% of the aggregate voting power of the total outstanding ordinary shares of the Issuer.

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1  Representing (i) 12,187,875 Class B ordinary shares that are convertible into the same number of Class A ordinary shares at any time at the option of the holder, and (ii) 6,700,000 Class A ordinary shares held by the holder. Sunrise Corporate Holding Ltd. is 100% owned by Mr. Sheng Chen.

2  The beneficial ownership percentage is calculated based on 817,170,095 ordinary shares of the Issuer as a single class, being the sum of (i) 671,234,982 Class A ordinary shares (excluding treasury shares and Class A ordinary shares in the form of ADSs that are reserved for issuance upon the exercise of share incentive awards) outstanding as of December 31, 2020, (ii) 145,875,113 Class B ordinary shares issued and outstanding as of December 31, 2020, and (iii) 60,000 Class C ordinary shares issued and outstanding as of December 31, 2020. The voting power of the shares beneficially owned by the Reporting Person represented 5.9% of the aggregate voting power of the total outstanding ordinary shares of the Issuer.

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1  Representing (i) 60,000 Class C ordinary shares that are convertible into the same number of Class A ordinary shares at any time at the option of the holder, (ii) 769,486 Class B ordinary shares that are convertible into the same number of Class A ordinary shares at any time at the option of the holder, and (iii) four Class A ordinary shares held by the holder. Personal Group Limited is 100% owned by Mr. Sheng Chen.

2  The beneficial ownership percentage is calculated based on 817,170,095 ordinary shares of the Issuer as a single class, being the sum of (i) 671,234,982 Class A ordinary shares (excluding treasury shares and Class A ordinary shares in the form of ADSs that are reserved for issuance upon the exercise of share incentive awards) outstanding as of December 31, 2020, (ii) 145,875,113 Class B ordinary shares issued and outstanding as of December 31, 2020, and (iii) 60,000 Class C ordinary shares issued and outstanding as of December 31, 2020. The voting power of the shares beneficially owned by the Reporting Person represented 0.4% of the aggregate voting power of the total outstanding ordinary shares of the Issuer.

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1  Representing 3,894,737 Class A ordinary shares held by such reporting person. Beacon Capital Group Inc. is 100% owned by Mr. Sheng Chen.

2  The beneficial ownership percentage is calculated based on 817,170,095 ordinary shares of the Issuer as a single class, being the sum of (i) 671,234,982 Class A ordinary shares (excluding treasury shares and Class A ordinary shares in the form of ADSs that are reserved for issuance upon the exercise of share incentive awards) outstanding as of December 31, 2020, (ii) 145,875,113 Class B ordinary shares issued and outstanding as of December 31, 2020, and (iii) 60,000 Class C ordinary shares issued and outstanding as of December 31, 2020. The voting power of the shares beneficially owned by the Reporting Person represented 0.2% of the aggregate voting power of the total outstanding ordinary shares of the Issuer.

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Item 1(a).                        Name of Issuer:

21Vianet Group, Inc.

Item 1(b).                        Address of Issuer’s Principal Executive Offices:

M5, 1 Jiuxianqiao East Road
Chaoyang District, Beijing 100016
The People’s Republic of China

Item 2(a).                        Name of Person Filing:

Sheng Chen
Fast Horse Technology Limited (“Fast Horse”)
Sunrise Corporate Holding Ltd. (“Sunrise”)
Personal Group Limited (“Personal”)
Beacon Capital Group Inc. (“Beacon”)

Item 2(b).                        Address of Principal Business Office or, if None, Residence:

For Sheng Chen:
Guanjie Building Southeast 1st Floor, 10# Jiuxianqiao East Road
Chaoyang District, Beijing 100016
The People’s Republic of China

For Fast Horse:
P.O. Box 957, Offshore Incorporations Centre
Road Town, Tortola, British Virgin Islands

For Sunrise:
Kingston Chambers, PO Box 173
Road Town, Tortola, British Virgin Islands

For Personal:
P.O. Box 957, Offshore Incorporations Centre
Road Town, Tortola, British Virgin Islands

For Beacon:
P.O. Box 957, Offshore Incorporations Centre
Road Town, Tortola, British Virgin Islands

Item 2(c)                            Citizenship:

Mr. Sheng Chen is a citizen of the People’s Republic of China.
Fast Horse is a British Virgin Islands company.
Sunrise is a British Virgin Islands company.
Personal is a British Virgin Islands company.
Beacon is a British Virgin Islands company.

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Item 2(d).                        Title of Class of Securities:

Class A Ordinary shares, par value $0.00001 per share

Item 2(e).                         CUSIP Number:

Class A ordinary shares: G91458 102

Item 3.                                        If this statement is filed pursuant to §§ 240.13d-1(b), or 240.13d-2(b) or (c), check whether the persons filing is a:

Not applicable

Item 4.                                       Ownership:

The following information with respect to the ownership of the ordinary shares of the issuer by the reporting persons is provided as of December 31, 2020. The table below is prepared based on 671,234,982  Class A ordinary shares (excluding treasury shares and Class A ordinary shares in the form of ADSs that are reserved for issuance upon the exercise of share incentive awards), 145,875,113 Class B ordinary shares, 60,000 Class C ordinary shares and 150,000 Series A perpetual convertible preferred shares issued and outstanding as of December 31, 2020.

For Sheng Chen:

Notes:

(1)               Representing (i) 6,700,000 Class A ordinary shares held by Sunrise; (ii) four Class A ordinary shares held by Personal; and (iii) 3,894,737 Class A ordinary shares held by Beacon. Mr. Chen is the sole shareholder of Sunrise, Personal and Beacon and may be deemed to be having sole voting and dispositive power over the shares held by Sunrise, Personal and Beacon.

(2)               Representing (i) 19,670,117 Class B ordinary shares held by Fast Horse, (ii) 12,187,875 Class B ordinary shares held by Sunrise; and (iii) 769,486 Class B ordinary shares held by Personal.

(3)               Representing 60,000 Class C ordinary shares held by Personal.

(4)               Representing (i) 19,670,117 Class B ordinary shares held by Fast Horse Technology Limited; (ii) 12,187,875 Class B ordinary shares and 6,700,000 Class A ordinary shares held by Sunrise Corporate Holding Ltd.; (iii) 60,000 Class C ordinary shares, 769,486 Class B ordinary shares and four Class A ordinary shares held by Personal Group Limited; (iv) 3,894,737 Class A ordinary shares held by Beacon Capital Group Inc.; and (v) 1,479,666 Class A ordinary shares upon vesting of Mr. Chen’s restricted share units within 60 days as of December 31, 2020.

(5)               To derive this percentage, (x) the numerator is 44,761,885, being the sum of (i) 60,000 Class C ordinary shares held by the reporting person, (ii) 32,627,478 Class B ordinary shares held by the reporting person, (iii) 10,594,741 Class A shares held by the reporting person, and (iv) 1,479,666 Class A ordinary shares that Mr. Chen has the right to acquire upon exercise of his restricted share units within 60 days after December 31, 2020, and (y) the denominator is the sum of (i) 671,234,982, being the number of the Company’s total Class A ordinary shares (excluding treasury shares and Class A ordinary shares in the form of ADSs that are reserved for issuance upon the exercise of share incentive awards) outstanding as of December 31, 2020, (ii) 145,875,113, being the number of the Company’s total Class B ordinary shares outstanding as of December 31, 2020, (iii) 60,000, being the number of the Company’s total Class C ordinary shares outstanding as of December 31, 2020, and (iv) 1,479,666 Class A ordinary shares that Mr. Chen has the right to acquire upon exercise of his restricted share units within 60 days after December 31, 2020.

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(6)               Percentage of aggregate voting power represents voting power of all ordinary shares held by the reporting person with respect to all outstanding shares of our Class A, Class B, Class C ordinary shares and Series A perpetual convertible preferred shares. Each holder of our Class A ordinary shares is entitled to one vote per Class A ordinary share. Each holder of our Class B ordinary shares is entitled to ten votes per Class B ordinary share. Each holder of our Class C ordinary shares is entitled to one vote per Class C ordinary share except for veto right on three corporate matters. The holders of our Series A perpetual convertible preferred shares are entitled to (i) vote with the holders of the Class A ordinary shares on any and all matters submitted for a vote of shareholders and (ii) a number of votes per such Preferred Shares equal to the number of Class A ordinary share into which each such Series A perpetual convertible preferred shares is then convertible at the time of the related record date as if the holders of such Series A perpetual convertible preferred shares were holders of Class A ordinary shares.

For Fast Horse Technology Limited:

Fast Horse Technology Limited is the record owner of 19,670,117 Class B ordinary shares. Fast Horse Technology Limited is wholly owned and controlled by Mr. Sheng Chen.

Notes:

(1)               Representing 19,670,117 Class B ordinary shares held by the reporting person.

(2)               To derive this percentage, (x) the numerator is 19,670,117, being the Class B ordinary shares held by the reporting person, and (y) the denominator is the sum of (i) 671,234,982, being the number of the Company’s total Class A ordinary shares (excluding treasury shares and Class A ordinary shares in the form of ADSs that are reserved for issuance upon the exercise of share incentive awards) outstanding as of December 31, 2020, (ii) 145,875,113, being the number of the Company’s total Class B ordinary shares outstanding as of December 31, 2020, and (iii) 60,000, being the number of the Company’s total Class C ordinary shares outstanding as of December 31, 2020.

(3)               Percentage of aggregate voting power represents voting power of all ordinary shares held by the reporting person with respect to all outstanding shares of our Class A, Class B, Class C ordinary shares and Series A perpetual convertible preferred shares. Each holder of our Class A ordinary shares is entitled to one vote per Class A ordinary share. Each holder of our Class B ordinary shares is entitled to ten votes per Class B ordinary share. Each holder of our Class C ordinary shares is entitled to one vote per Class C ordinary share except for veto right on three corporate matters. The holders of our Series A perpetual convertible preferred shares are entitled to (i) vote with the holders of the Class A ordinary shares on any and all matters submitted for a vote of shareholders and (ii) a number of votes per such Preferred Shares equal to the number of Class A ordinary share into which each such Series A perpetual convertible preferred shares is then convertible at the time of the related record date as if the holders of such Series A perpetual convertible preferred shares were holders of Class A ordinary shares.

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For Sunrise Corporate Holding Ltd.:

Sunrise Corporate Holding Ltd. is the record owner of 12,187,875 Class B ordinary shares and 6,700,000 Class A ordinary shares of the Issuer. Sunrise Corporate Holding Ltd. is wholly owned and controlled by Mr. Sheng Chen.

Notes:

(1)               Representing 6,700,000 Class A ordinary shares held by Sunrise.

(2)               Representing 12,187,875 Class B ordinary shares held by Sunrise.

(3)               To derive this percentage, (x) the numerator is 18,887,875, being the sum of 12,187,875 Class B ordinary shares and 6,700,000 Class A ordinary shares held by Sunrise, and (y) the denominator is the sum of (i) 671,234,982, being the number of the Company’s total Class A ordinary shares (excluding treasury shares and Class A ordinary shares in the form of ADSs that are reserved for issuance upon the exercise of share incentive awards) outstanding as of December 31, 2020, (ii) 145,875,113, being the number of the Company’s total Class B ordinary shares outstanding as of December 31, 2020, and (iii) 60,000, being the number of the Company’s total Class C ordinary shares outstanding as of December 31, 2020.

(4)               Percentage of aggregate voting power represents voting power of all ordinary shares held by the reporting person with respect to     all outstanding shares of our Class A, Class B, Class C ordinary shares and Series A perpetual convertible preferred shares. Each holder of our Class A ordinary shares is entitled to one vote per Class A ordinary share. Each holder of our Class B ordinary shares is entitled to ten votes per Class B ordinary share. Each holder of our Class C ordinary shares is entitled to one vote per Class C ordinary share except for veto right on three corporate matters. The holders of our Series A perpetual convertible preferred shares are entitled to (i) vote with the holders of the Class A ordinary shares on any and all matters submitted for a vote of shareholders and (ii) a number of votes per such Preferred Shares equal to the number of Class A ordinary share into which each such Series A perpetual convertible preferred shares is then convertible at the time of the related record date as if the holders of such Series A perpetual convertible preferred shares were holders of Class A ordinary shares.

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For Personal Group Limited:

Personal Group Limited is the record owner of 60,000 Class C ordinary shares, 769,486 Class B ordinary shares and 4 Class A ordinary shares of the Issuer. Personal Group Limited is wholly owned and controlled by Mr. Sheng Chen.

Notes:

(1)               Representing four Class A ordinary shares held by Personal.

(2)               Representing 769,486 Class B ordinary shares held by Personal.

(3)               Representing 60,000 Class C ordinary shares held by Personal.

(4)               To derive this percentage, (x) the numerator is 829,490, being the sum of four Class A ordinary shares, 769,486 Class B ordinary shares and 60,000 Class C ordinary shares held by Personal, and (y) the denominator is the sum of (i) 671,234,982, being the number of the Company’s total Class A ordinary shares (excluding treasury shares and Class A ordinary shares in the form of ADSs that are reserved for issuance upon the exercise of share incentive awards) outstanding as of December 31, 2020, (ii) 145,875,113, being the number of the Company’s total Class B ordinary shares outstanding as of December 31, 2020, and (iii) 60,000, being the number of the Company’s total Class C ordinary shares outstanding as of December 31, 2020.

(5)               Percentage of aggregate voting power represents voting power of all ordinary shares held by the reporting person with respect to all outstanding shares of our Class A, Class B, Class C ordinary shares and Series A perpetual convertible preferred shares. Each holder of our Class A ordinary shares is entitled to one vote per Class A ordinary share. Each holder of our Class B ordinary shares is entitled to ten votes per Class B ordinary share. Each holder of our Class C ordinary shares is entitled to one vote per Class C ordinary share except for veto right on three corporate matters. The holders of our Series A perpetual convertible preferred shares are entitled to (i) vote with the holders of the Class A ordinary shares on any and all matters submitted for a vote of shareholders and (ii) a number of votes per such Preferred Shares equal to the number of Class A ordinary share into which each such Series A perpetual convertible preferred shares is then convertible at the time of the related record date as if the holders of such Series A perpetual convertible preferred shares were holders of Class A ordinary shares.

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For Beacon Capital Group Inc.:

Beacon Capital Group Inc. is the record owner of 3,894,737 Class A ordinary shares of the Issuer. Beacon Capital Group Inc. is wholly owned and controlled by Mr. Sheng Chen.

Notes:

(1)               Representing 3,894,737 Class A ordinary shares held by Beacon.

(2)               To derive this percentage, (x) the numerator is 3,894,737, being the number of 3,894,737 Class A shares held by the reporting person, and (y) the denominator is the sum of (i) 671,234,982, being the number of the Company’s total Class A ordinary shares (excluding treasury shares and Class A ordinary shares in the form of ADSs that are reserved for issuance upon the exercise of share incentive awards) outstanding as of December 31, 2020, (ii) 145,875,113, being the number of the Company’s total Class B ordinary shares outstanding as of December 31, 2020 that are convertible into the same number of Class A ordinary shares, and (iii) 60,000, being the number of the Company’s total Class C ordinary shares outstanding as of as of December 31, 2020 that are convertible into the same number of Class A ordinary shares.

(3)               Percentage of aggregate voting power represents voting power of all ordinary shares held by the reporting person with respect to all outstanding shares of our Class A, Class B, Class C ordinary shares and Series A perpetual convertible preferred shares. Each holder of our Class A ordinary shares is entitled to one vote per Class A ordinary share. Each holder of our Class B ordinary shares is entitled to ten votes per Class B ordinary share. Each holder of our Class C ordinary shares is entitled to one vote per Class C ordinary share except for veto right on three corporate matters. The holders of our Series A perpetual convertible preferred shares are entitled to (i) vote with the holders of the Class A ordinary shares on any and all matters submitted for a vote of shareholders and (ii) a number of votes per such Preferred Shares equal to the number of Class A ordinary share into which each such Series A perpetual convertible preferred shares is then convertible at the time of the related record date as if the holders of such Series A perpetual convertible preferred shares were holders of Class A ordinary shares.

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Item 5.                                        Ownership of Five Percent or Less of a Class:

Not applicable

Item 6.                                       Ownership of More than Five Percent on Behalf of Another Person:

Not applicable

Item 7.                                        Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on by the Parent Holding Company or Controlling Person:

Not applicable

Item 8.                                        Identification and Classification of Members of the Group:

Not applicable

Item 9.                                       Notice of Dissolution of Group:

Not applicable

Item 10.                                Certifications:

Not applicable

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After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

Dated: February 10, 2021

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LIST OF EXHIBITS

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