X0306 4 2015-03-17 1 0001608249 Zayo Group Holdings, Inc. ZAYO 0001365607 OAK INVESTMENT PARTNERS XII L P C/O OAK INVESTMENT PARTNERS 901 MAIN AVENUE, SUITE 600 NORWALK CT 06851 0 0 1 0 0001622025 Oak Associates XII, LLC C/O OAK INVESTMENT PARTNERS 901 MAIN AVENUE, SUITE 600 NORWALK CT 06851 0 0 1 0 Common Stock 2015-03-17 4 S 0 3550534 26.5295 D 22446773 I See Footnote The shares are directly held by Oak Investment Partners XII, L.P. Oak Associates XII, LLC is the general partner of Oak Investment Partners XII, L.P. Oak Investment Partners XII, L.P. is managed by a seven-member board of managers (the "Oak Board of Managers"). Each of Oak Associates XII, LLC and the individual members of the Oak Board of Managers disclaims beneficial ownership of the shares held of record by Oak Investment Partners XII, L.P., 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. OAK INVESTMENT PARTNERS, XII, LIMITED PARTNERSHIP, By: Oak Associates XII, LLC, its general partner, By: /s/ Edward F. Glassmayer, Managing Partner 2015-05-20 OAK ASSOCIATES XII, LLC, By: /s/ Edward F. Glassmayer, Managing Partner 2015-05-20