Sec Form 4 Filing - Charlesbank Equity Fund VI, Limited Partnership @ Zayo Group Holdings, Inc. - 2015-03-17

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 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 Charlesbank Equity Fund VI, Limited Partnership 2. Issuer Name and Ticker or Trading Symbol Zayo Group Holdings, Inc. [ ZAYO] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O CHARLESBANK CAPITAL PARTNERS, LLC, 200 CLARENDON, 54TH FLOOR 3. Date of Earliest Transaction (MM/DD/YY) 03/17/2015 (Street) BOSTON, MA02116 4. If Amendment, Date Original Filed (MM/DD/YY) 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 (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 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 03/17/2015 S 3,107,869 D $ 26.5295 19,832,868 I See Footnotes ( 1 ) ( 2 )

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 (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 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 (MM/DD/YY) 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 Charlesbank Equity Fund VI, Limited Partnership C/O CHARLESBANK CAPITAL PARTNERS, LLC 200 CLARENDON, 54TH FLOOR BOSTON, MA02116 X Charlesbank Equity Fund VI GP, Limited Partnership C/O CHARLESBANK CAPITAL PARTNERS, LLC 200 CLARENDON, 54TH FLOOR BOSTON, MA02116 X CHARLESBANK CAPITAL PARTNERS LLC C/O CHARLESBANK CAPITAL PARTNERS, LLC 200 CLARENDON, 54TH FLOOR BOSTON, MA02116 X CB Offshore Equity Fund VI LP C/O CHARLESBANK CAPITAL PARTNERS, LLC 200 CLARENDON, 54TH FLOOR BOSTON, MA02116 X Charlesbank Equity Coinvestment Fund VI Limited Partnership C/O CHARLESBANK CAPITAL PARTNERS, LLC 200 CLARENDON, 54TH FLOOR BOSTON, MA02116 X CHARLESBANK COINVESTMENT PARTNERS LIMITED PARTNERSHIP C/O CHARLESBANK CAPITAL PARTNERS, LLC 200 CLARENDON, 54TH FLOOR BOSTON, MA02116 X Signatures CHARLESBANK EQUITY FUND VI, LIMITED PARTNERSHIP, By: Charlesbank Equity Fund VI GP, Limited Partnership, its general partner, By: Charlesbank Capital Partners, LLC, its general partner, By: /s/ Tami Nason, General Counsel 03/24/2015 Signature of Reporting Person Date CHARLESBANK EQUITY FUND VI GP, LIMITED PARTNERSHIP, By: Charlesbank Capital Partners, LLC, its general partner, By: /s/ Tami Nason, General Counsel 03/24/2015 Signature of Reporting Person Date CHARLESBANK CAPITAL PARTNERS, LLC, By: /s/ Tami Nason, General Counsel 03/24/2015 Signature of Reporting Person Date CB OFFSHORE EQUITY FUND VI, L.P., By: Charlesbank Equity Fund VI GP, Limited Partnership, its general partner, By: Charlesbank Capital Partners, LLC, its general partner, By: /s/ Tami Nason, General Counsel 03/24/2015 Signature of Reporting Person Date CHARLESBANK EQUITY COINVESTMENT FUND VI, LIMITED PARTNERSHIP, By: Charlesbank Equity Fund VI GP, Limited Partnership, its general partner, By: Charlesbank Capital Partners, LLC, its general partner, By: /s/ Tami Nason, General Counsel 03/24/2015 Signature of Reporting Person Date CHARLESBANK COINVESTMENT PARTNERS, LIMITED PARTNERSHIP, By: Charlesbank Capital Partners, LLC, its general partner, By: /s/ Tami Nason, General Counsel 03/24/2015 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Following the reported transaction, consists of (i) 17,032,309 shares held of record by Charlesbank Equity Fund VI, Limited Partnership ("Fund VI"), (ii) 1,979,491 shares held of record by CB Offshore Equity Fund VI,L.P. ("Offshore VI"), (iii) 763,318 shares held of record by Charlesbank Equity Coinvestment Fund VI, Limited Partnership ("Coinvest VI" and, together with Fund VI and Offshore VI, the "Charlesbank Funds") and(iv) 57,750 shares held of record by Charlesbank Coinvestment Partners, Limited Partnership ("Coinvest"). Charlesbank Equity Fund VI GP, Limited Partnership ("Equity VI GP") is the general partner of each of theCharlesbank Funds. Charlesbank Capital Partners, LLC ("Charlesbank") is the general partner of Coinvest and Equity VI GP. (continued) ( 2 )(continued from footnote 1) Pursuant to an investment and advisory agreement with each of the Charlesbank Funds, an investment committee (the "Investment Committee") consisting of ten members, each a ManagingDirector of Charlesbank, has investment and voting authority over the securities held by the Charlesbank Funds. Each of the foregoing entities and the individual members of the Investment Committee disclaimsbeneficial ownership of the shares held of record by the Charlesbank Funds and Coinvest, except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that the reporting personis the beneficial owner of the securities for purposes of Section 16 or for any other purpose.

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.

* If the form is filed by more than one reporting person, see Instruction 4(b)(v).

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