X0306 4 2015-03-17 1 0001608249 Zayo Group Holdings, Inc. ZAYO 0001359354 M/C VENTURE PARTNERS VI L P C/O M/C PARTNERS 75 STATE STREET, SUITE 2500 BOSTON MA 02109 0 0 1 0 0001622210 M/C Venture Partners, LLC C/O M/C PARTNERS 75 STATE STREET, SUITE 2500 BOSTON MA 02109 0 0 1 0 0001622354 M/C VP VI, L.P. C/O M/C PARTNERS 75 STATE STREET, SUITE 2500 BOSTON MA 02109 0 0 1 0 0001305476 M/C Venture Investors LLC C/O M/C PARTNERS 75 STATE STREET, SUITE 2500 BOSTON MA 02109 0 0 1 0 0001297712 M/C Venture Partners V, L.P. C/O M/C PARTNERS 75 STATE STREET, SUITE 2500 BOSTON MA 02109 0 0 1 0 0001297713 M/C VP V, LLC C/O M/C PARTNERS 75 STATE STREET, SUITE 2500 BOSTON MA 02109 0 0 1 0 0001305228 Chestnut Venture Partners LP C/O M/C PARTNERS 75 STATE STREET, SUITE 2500 BOSTON MA 02109 0 0 1 0 0001305169 Chestnut Street Partners Inc C/O M/C PARTNERS 75 STATE STREET, SUITE 2500 BOSTON MA 02109 0 0 1 0 0001633221 Corelink Data Centers, LLC C/O M/C PARTNERS 75 STATE STREET, SUITE 2500 BOSTON MA 02109 0 0 1 0 Common Stock 2015-03-17 4 S 0 3216055 26.5295 D 20997419 I See Footnotes Prior to the transaction reported herein, consists of (i) 23,314,888 shares held of record by M/C Venture Partners VI, L.P., (ii) 723,716 shares held of record by M/C Venture Investors L.L.C., (iii) 174,870 shares held of record by Core link Data Centers, LLC (together, the "M/C Shareholders"). M/C Venture Partners V, LP, M/C VP V, LLC, Chestnut Venture Partners, LP, and Chestnut Street Partners, Inc. hold no shares of the issuer and are included on this form for the sole purpose of reporting that they are no longer subject to the Section 16. M/C Venture Partners VI,L.P. is the managing member of Corelink Data Centers, LLC. M/C VP VI, L.P. is the sole general partner of M/C Venture Partners VI, L.P. and M/C Venture Partners, LLC is the sole general partner of M/C VP VI, L.P. M/C VP V LLC is the sole general partner of M/C Venture Partners V, L.P. Chestnut Street Partners, Inc. is the sole general partner of Chestnut Venture Partners, L.P. As the Managers of M/C Venture Partners, LLC, M/C Venture Investors L.L.C. and M/C VP V LLC, Gillis S. Cashman, Brian M. Clark, David D. Croll, James F. Wade and John W. Watkins collectively have direct or indirect investment and voting authority over the securities held by M/C Venture Partners VI, L.P., M/C Venture Investors L.L.C. and M/C Venture Partners V, L.P. David D. Croll and James F. Wade collectively have investment and voting authority over the securities held by Chestnut Venture Partners, L.P. Each of the foregoing entities and individuals disclaims beneficial ownership of the shares held of record by the M/C 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. M/C VENTURE PARTNERS VI, L.P., By: M/C VP VI, LLC, its general partner, By: M/C Venture Partners, LLC, its general partner, By: /s/ Gillis S. Cashman, Manager 2015-05-20 M/C VP VI, LLC, By: M/C Venture Partners, LLC, its general partner, By: /s/ Gillis S. Cashman. Manager 2015-05-20 M/C VENTURE PARTNERS, LLC, By: /s/ Gillis S. Cashman, Manager 2015-05-20 M/C VENTURE INVESTORS L.L.C., By: /s/ Gillis S. Cashman, Manager 2015-05-20 M/C VENTURE PARTNERS V, L.P., By: M/C VP V, LLC, its general partner, By: /s/ Gillis S. Cashman, Manager 2015-05-20 M/C VP V, LLC, By: /s/ Gillis S. Cashman, Manager 2015-05-20 CHESTNUT VENTURE PARTNERS, L.P., By: Chestnut Street Partners, Inc., its general partner, By: /s/ David D. Croll, President 2015-05-20 CHESTNUT STREET PARTNERS, INC., By: /s/ David D. Croll, President 2015-05-20 CORELINK DATA CENTERS, LLC, By: M/C Venture Partners VI, L.P., its managing member, By: M/C VP VI, L.P., its general partner, By: M/C Venture Partners, LLC, its general partner, By: /s/ Gillis S. Cashman, Manager 2015-05-20