X0206 3 2014-10-16 0 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 Common Stock 25437645 I See Footnotes Consists of (i) 24,160,854 shares held of record by M/C Venture Partners VI, L.P., (ii) 757,871 shares held of record by M/C Venture Investors L.L.C., (iii) 497,320 shares held of record by M/C Venture Partners V, L.P. and (iv) 21,600 shares held of record by Chestnut Venture Partners, L.P. (together, the "M/C Shareholders"). 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. (continued) 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. (continued from footnote 1) 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 2014-10-16 M/C VP VI, LLC, By: M/C Venture Partners, LLC, its general partner, By: /s/ Gillis S. Cashman, Manager 2014-10-16 M/C VENTURE PARTNERS, LLC, By: /s/ Gillis S. Cashman, Manager 2014-10-16 M/C VENTURE INVESTORS, L.L.C., By: /s/ Gillis S. Cashman, Manager 2014-10-16 M/C VENTURE PARTNERS V, L.P., By: M/C VP V, LLC, its general partner, By: /s/ Gillis S. Cashman, Manager 2014-10-16 M/C VP V, LLC, By: /s/ Gillis S. Cashman, Manager 2014-10-16 CHESTNUT VENTURE PARTNERS, L.P., By: Chestnut Street Partners, Inc., its general partner, By: /s/ David D. Croll, President 2014-10-16 CHESTNUT STREET PARTNERS, INC., By: /s/ David D. Croll, President 2014-10-16