CONCENTRIC NETWORK CORP

Q: Mar 31 2000

FY: Dec 31 1999

FY: Dec 31 1999

Q: Sep 30 1999

Q: Jun 30 1999

Q: Mar 31 1999

FY: Dec 31 1998

FY: Dec 31 1998

Q: Sep 30 1998

Q: Jun 30 1998

Q: May 15 1998

FY: Dec 31 1997

Q: Nov 14 1997

Q: Aug 14 1997

2,7

5

5,7

5,7

2,7

2,7

Current report pursuant to Section 13 or 15(d)

5,7

Certification of termination of registration of a class of securities (Section 12(g))

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

No description available

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

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

Prospectus Supplement with Pricing Information

Registration statement under Securities Act of 1933 (amendment)

Registration statement under Securities Act of 1933 (amendment)

Registration statement under Securities Act of 1933

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

Registration statement under Securities Act of 1933 (amendment)

Registration statement under Securities Act of 1933

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

Registration statement under Securities Act of 1933 (amendment)

Registration statement under Securities Act of 1933

Prospectus Supplement with Pricing Information

Amended Initial Registration Statement

Amended Initial Registration Statement

Registration (IPO) statement under Securities Act of 1933

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

Definitive Proxy Statement

Definitive Proxy Statement

Definitive Proxy Statement

SOFTBANK CORP

FMR CORP

MORGAN J P & CO INC

MICROSOFT CORP

MORGAN J P & CO INC

KLEINER PERKINS CAUFIELD & BYERS VII L P

GOLDMAN SACHS GROUP LP

DENVER INVESTMENT ADVISORS LLC

SOFTBANK CORP

FMR CORP

SBC COMMUNICATIONS INC

WILLIAMS COMMUNICATIONS GROUP INC

WILLIAMS COMMUNICATIONS GROUP INC

SBC COMMUNICATIONS INC

WILLIAMS COMMUNICATIONS GROUP INC

WILLIAMS COMMUNICATIONS GROUP INC

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