FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP OF SECURITIES Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person * GLASSMEYER EDWARD F   2. Issuer Name and Ticker or Trading Symbol COGENT COMMUNICATIONS GROUP INC [CCOI] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) __X__ Director __X__ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O OAK INVESTMENT PARTNERS, ONE GORHAM ISLAND 3. Date of Earliest Transaction (Month/Day/Year) 06/07/2006 (Street) WESTPORT, CT 06880 4. If Amendment, Date Original Filed(Month/Day/Year) 6. Individual or Joint/Group Filing(Check Applicable Line) ___ Form filed by One Reporting Person _X_ Form filed by More than One Reporting Person (City) (State) (Zip) Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned

1.Title of Security (Instr. 3) 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 06/07/2006   S   869,877 D $ 8.5275 3,711,469 I See Note (1) Common Stock 06/07/2006   S   9,399 D $ 8.5275 40,100 I See Note (2) Common Stock 06/07/2006   S   20,724 D $ 8.5275 88,422 I See Note (3) Common Stock               3,750 (4) I See Note (4)

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
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Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)

1. Title of Derivative Security (Instr. 3)

2. Conversion or Exercise Price of Derivative Security

3. Transaction Date (Month/Day/Year)

3A. Deemed Execution Date, if any (Month/Day/Year)

4. Transaction Code (Instr. 8)

5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5)

6. Date Exercisable and Expiration Date (Month/Day/Year)

7. Title and Amount of Underlying Securities (Instr. 3 and 4)

8. Price of Derivative Security (Instr. 5)

9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)

10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4)

11. Nature of Indirect Beneficial Ownership (Instr. 4)

Code

V

(A)

(D)

Date Exercisable

Expiration Date

Title

Amount or Number of Shares

Reporting Owners

Reporting Owner Name / Address	Relationships
	Director	10% Owner	Officer	Other
GLASSMEYER EDWARD F C/O OAK INVESTMENT PARTNERS ONE GORHAM ISLAND WESTPORT, CT 06880	X	X
OAK MANAGEMENT CORP ONE GORHAM ISLAND WESTPORT, CT 06880		X
OAK INVESTMENT PARTNERS IX L P ONE GORHAM ISLAND WESTPORT, CT 06880		X
OAK IX AFFILIATES FUND LP ONE GORHAM ISLAND WESTPORT, CT 06880		X
OAK IX AFFILIATES FUND A LP ONE GORHAM ISLAND WESTPORT, CT 06880		X

Signatures

Edward F. Glassmeyer		06/08/2006
**Signature of Reporting Person		Date
Edward F. Glassmeyer, Managing Member of Oak Associates IX, L.L.C., the General Partner of Oak Investment Partners IX, L.P.		06/08/2006
**Signature of Reporting Person		Date
Edward F. Glassmeyer, Managing Member of Oak IX Affiliates, L.L.C., the General Partner of Oak IX Affiliates Fund, L.P.		06/08/2006
**Signature of Reporting Person		Date
Edward F. Glassmeyer, Managing Member of Oak IX Affiliates, L.L.C., the General Partner of Oak IX Affiliates Fund - A, L.P.		06/08/2006
**Signature of Reporting Person		Date
Edward F. Glassmeyer, President of Oak Management Corporation		06/08/2006
**Signature of Reporting Person		Date

Explanation of Responses:

*	If the form is filed by more than one reporting person, see Instruction 4(b)(v).
**	Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1)	Represents shares directly owned by Oak Investment Partners IX, Limited Partnership ("Oak IX, L.P.")
(2)	Represents shares directly owned by Oak Affiliates Fund, Limited Partnership ("Oak IX Affiliates, L.P.")
(3)	Represents shares directly owned by Oak Affiliates Fund - A, Limited Partnership ("Oak IX Affiliates - A, L.P.")
(4)	Represents shares directly owned by Oak Management Corporation ("OMC")
Remarks: Remarks: Mr. Glassmeyer is the President of Oak Management Corporation; a Managing Member of Oak Associates IX, L.L.C., the General Partner of Oak IX, L.P.; and a Managing Member of Oak IX Affiliates, L.L.C., the General Partner of Oak IX Affiliates, L.P. and Oak IX Affiliates - A, L.P. Oak IX, L.P., Oak IX Affiliates, L.P., Oak IX Affiliates-A, L.P. and OMC are no longer subject to Section 16 because the Reporting Persons are no longer 10% owners. Each Reporting Person disclaims the existence of a "group" and disclaims beneficial ownership of any securities (except to the extent of such Reporting Person's pecuniary interest in such securities) other than any securities reported herein as being directly owned by such Reporting Person, and this report shall not be deemed an admission that such Reporting Person is the beneficial owner of any such securities for purposes of Section 16 or for any other purpose.

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