Sec Form 4 Filing - GTCR FUND X/A LP @ Zayo Group Holdings, Inc. - 2018-03-12

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 GTCR FUND X/A LP 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) 300 NORTH LASALLE STREET, SUITE 5600 3. Date of Earliest Transaction (MM/DD/YY) 03/12/2018 (Street) CHICAGO, IL60654 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 03/12/2018 S 4,675,000 D $ 37.05 22,448,334 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 GTCR FUND X/A LP 300 NORTH LASALLE STREET, SUITE 5600 CHICAGO, IL60654 X GTCR FUND X/C LP 300 NORTH LASALLE STREET, SUITE 5600 CHICAGO, IL60654 X GTCR Investors (CII) LP 300 NORTH LASALLE STREET, SUITE 5600 CHICAGO, IL60654 X GTCR Partners X/A&C LP 300 NORTH LASALLE STREET, SUITE 5600 CHICAGO, IL60654 X GTCR CO-INVEST X LP 300 NORTH LASALLE STREET, SUITE 5600 CHICAGO, IL60654 X GTCR Investment X LLC 300 NORTH LASALLE STREET, SUITE 5600 CHICAGO, IL60654 X Signatures GTCR FUND X/A LP, By: GTCR Partners X/A&C LP, its general partner, By: GTCR Investment X LLC, its general partner, By: /s/ Jeffrey S. Wright, Principal and Associate General Counsel 03/14/2017 Signature of Reporting Person Date GTCR INVESTORS (CII) LP, By: GTCR Partners X/A&C LP, its general partner, By: GTCR Investment X LLC, its general partner, By: /s/ Jeffrey S. Wright, Principal and Associate General Counsel 03/14/2017 Signature of Reporting Person Date GTCR PARTNERS X/A&C LP, By: GTCR Investment X LLC, its general partner, By: /s/ Jeffrey S. Wright, Principal and Associate General Counsel 03/14/2017 Signature of Reporting Person Date GTCR INVESTMENT X LLC, By: /s/ Jeffrey S. Wright, Principal and Associate General Counsel 03/14/2017 Signature of Reporting Person Date GTCR FUND X/C LP, By: GTCR Partners X/A&C LP, its general partner, By: GTCR Investment X LLC, its general partner, By: /s/ Jeffrey S. Wright, Principal and Associate General Counsel 03/14/2017 Signature of Reporting Person Date GTCR CO-INVEST X LP, By: GTCR Investment X LLC, its general partner, By: /s/ Jeffrey S. Wright, Principal and Associate General Counsel 03/14/2017 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Consists of (i) 11,227,040 shares held of record by GTCR Fund X/A LP; (ii) 3,203,744 shares held of record by GTCR Fund X/C LP; (iii) 96,849 shares held of record by GTCR Co-Invest X LP; and (iv) 7,920,701 shares held of record by GTCR Investors (CII) LP (collectively, the "GTCR Shareholders"). GTCR Partners X/A&C LP is the general partner of each of GTCR Fund X/A LP, GTCR Fund X/C LP and GTCR Investors (CII) LP. GTCR Investment X LLC is the general partner of each of GTCR Co-Invest X LP and GTCR Partners X/A&C LP. GTCR Investment X LLC is managed by an eight-member board of managers (the "GTCR Board of Managers"). (continued) ( 2 )(continued from footnote 1) Each of the foregoing entities and the individual members of the GTCR Board of Managers disclaims beneficial ownership of the shares held of record by the GTCR Shareholders, except to the extent of their pecuniary interest therein, and this report shall not be deemed an admission that the reporting person is 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).

** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).

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