X0306 4 2018-05-08 0 0001366527 Carbon Black, Inc. CBLK 0001357840 Highland Entrepreneurs Fund VII Limited Partnership C/O HIGHLAND CAPITAL PARTNERS ONE BROADWAY, 16TH FLOOR CAMBRIDGE MA 02142 0 0 1 0 0001407941 HEF VI, Limited Partnership C/O HIGHLAND CAPITAL PARTNERS ONE BROADWAY, 16TH FLOOR CAMBRIDGE MA 02142 0 0 1 0 Common Stock 2018-05-08 4 C 0 3514161 A 4270065 I By Highland Capital Partners VI Limited Partnership Common Stock 2018-05-08 4 C 0 1926577 A 2340874 I By Highland Capital Partners VI-B Limited Partnership Common Stock 2018-05-08 4 C 0 174059 A 211495 I By Highland Entrepreneurs' Fund VI Limited Partnership Common Stock 2018-05-08 4 C 0 1093318 A 1093318 I By Highland Capital Partners VII Limited Partnership Common Stock 2018-05-08 4 C 0 264931 A 264931 I By Highland Capital Partners VII-B Limited Partnership Common Stock 2018-05-08 4 C 0 385824 A 385824 I By Highland Capital Partners VII-C Limited Partnership Common Stock 2018-05-08 4 C 0 34258 A 34258 I By Highland Entrepreneurs' Fund VII Limited Partnership Series B Convertible Preferred Stock 2018-05-08 4 C 0 4794437 D Common Stock 2397218 0 I By Highland Capital Partners VI Limited Partnership Series B Convertible Preferred Stock 2018-05-08 4 C 0 2628466 D Common Stock 1314233 0 I By Highland Capital Partners VI-B Limited Partnership Series B Convertible Preferred Stock 2018-05-08 4 C 0 237472 D Common Stock 118736 0 I By Highland Entrepreneurs' Fund VI Limited Partnership Series C Convertible Preferred Stock 2018-05-08 4 C 0 1544087 D Common Stock 772043 0 I By Highland Capital Partners VI Limited Partnership Series C Convertible Preferred Stock 2018-05-08 4 C 0 846518 D Common Stock 423259 0 I By Highland Capital Partners VI-B Limited Partnership Series C Convertible Preferred Stock 2018-05-08 4 C 0 76480 D Common Stock 38240 0 I By Highland Entrepreneurs' Fund VI Limited Partnership Series D Convertible Preferred Stock 2018-05-08 4 C 0 689800 D Common Stock 344900 0 I By Highland Capital Partners VI Limited Partnership Series D Convertible Preferred Stock 2018-05-08 4 C 0 378171 D Common Stock 189085 0 I By Highland Capital Partners VI-B Limited Partnership Series D Convertible Preferred Stock 2018-05-08 4 C 0 34166 D Common Stock 17083 0 I By Highland Entrepreneurs' Fund VI Limited Partnership Series E Convertible Preferred Stock 2018-05-08 4 C 0 1149874 D Common Stock 574937 0 I By Highland Capital Partners VII Limited Partnership Series E Convertible Preferred Stock 2018-05-08 4 C 0 278637 D Common Stock 139318 0 I By Highland Capital Partners VII-B Limited Partnership Series E Convertible Preferred Stock 2018-05-08 4 C 0 405783 D Common Stock 202891 0 I By Highland Capital Partners VII-C Limited Partnership Series E Convertible Preferred Stock 2018-05-08 4 C 0 36031 D Common Stock 18015 0 I By Highland Entrepreneurs' Fund VII Limited Partnership Series F Convertible Preferred Stock 2018-05-08 4 C 0 1036762 D Common Stock 518381 0 I By Highland Capital Partners VII Limited Partnership Series F Convertible Preferred Stock 2018-05-08 4 C 0 251227 D Common Stock 125613 0 I By Highland Capital Partners VII-B Limited Partnership Series F Convertible Preferred Stock 2018-05-08 4 C 0 365866 D Common Stock 182933 0 I By Highland Capital Partners VII-C Limited Partnership Series F Convertible Preferred Stock 2018-05-08 4 C 0 32486 D Common Stock 16243 0 I By Highland Entrepreneurs' Fund VII Limited Partnership Each share of preferred stock automatically converted into Common Stock on a 1-for-2 basis upon the closing of the Issuer's initial public offering. The shares have no expiration date. The shares are held directly by Highland Capital Partners VI Limited Partnership ("Highland Capital VI"). The general partner of Highland Capital VI is Highland Management Partners VI Limited Partnership ("HMP VI LP"). The general partner of HMP VI LP is Highland Management Partners VI, Inc. ("Highland Management"). Each of HMP VI LP and Highland Management disclaims Section 16 beneficial ownership of all shares except to the extent of their pecuniary interest, if any, therein. This report shall not be deemed to be an admission that the reporting persons are the beneficial owners of such securities for purposes of Section 16 or for any other purpose. The shares are held directly by Highland Capital Partners VI-B Limited Partnership ("Highland Capital VI-B"). The general partner of Highland Capital VI-B is HMP VI LP. The general partner of HMP VI LP is Highland Management. Each of HMP VI LP and Highland Management disclaims Section 16 beneficial ownership of all shares except to the extent of their pecuniary interest, if any, therein. This report shall not be deemed to be an admission that the reporting persons are the beneficial owners of such securities for purposes of Section 16 or for any other purpose. The shares are held directly by Highland Entrepreneurs' Fund VI Limited Partnership ("Highland VI Entrepreneurs' Fund"). The general partner of Highland VI Entrepreneurs' Fund is HEF VI Limited Partnership ("HEF"). The general partner of HEF is Highland Management. Each of HEF and Highland Management disclaims Section 16 beneficial ownership of all shares except to the extent of their pecuniary interest, if any, therein. This report shall not be deemed to be an admission that the reporting persons are the beneficial owners of such securities for purposes of Section 16 or for any other purpose. The shares are held directly by Highland Capital Partners VII Limited Partnership ("Highland Capital VII"). The general partner of Highland Capital VII is Highland Management Partners VII Limited Partnership ("HMP VII LP"). The general partner of HMP VII LP is Highland Management Partners VII, LLC ("HMP VII LLC"). Each of HMP VII LP and HMP VII LLC disclaims Section 16 beneficial ownership of all shares except to the extent of their pecuniary interest, if any, therein. This report shall not be deemed to be an admission that the reporting persons are the beneficial owners of such securities for purposes of Section 16 or for any other purpose. The shares are held directly by Highland Capital Partners VII-B Limited Partnership ("Highland Capital VII-B"). The general partner of Highland Capital VII-B is HMP VII LP. The general partner of HMP VII LP is HMP VII LLC. Each of HMP VII LP and HMP VII LLC disclaims Section 16 beneficial ownership of all shares except to the extent of their pecuniary interest, if any, therein. This report shall not be deemed to be an admission that the reporting persons are the beneficial owners of such securities for purposes of Section 16 or for any other purpose. The shares are held directly by Highland Capital Partners VII-C Limited Partnership ("Highland Capital VII-C"). The general partner of Highland Capital VII-C is HMP VII LP. The general partner of HMP VII LP is HMP VII LLC. Each of HMP VII LP and HMP VII LLC disclaims Section 16 beneficial ownership of all shares except to the extent of their pecuniary interest, if any, therein. This report shall not be deemed to be an admission that the reporting persons are the beneficial owners of such securities for purposes of Section 16 or for any other purpose. The shares are held directly by Highland Entrepreneurs' Fund VII Limited Partnership ("Highland VII Entrepreneurs' Fund"). The general partner of Highland VII Entrepreneurs' Fund is HMP VII LP. The general partner of HMP VII LP is HMP VII LLC. Each of HMP VII LP and HMP VII LLC disclaims Section 16 beneficial ownership of all shares except to the extent of his their pecuniary interest, if any, therein. This report shall not be deemed to be an admission that the reporting persons are the beneficial owners of such securities for purposes of Section 16 or for any other purpose. Because no more than 10 reporting persons can file any Form 4 through the Securities and Exchange Commission's EDGAR system, Highland Management Partners VI, Inc., Highland Management Partners VI Limited Partnership, Highland Capital Partners VI-B Limited Partnership, Highland Capital Partners VI Limited Partnership, Highland Entrepreneurs' Fund VI Limited Partnership, Highland Management Partners VII, LLC, Highland Management Partners VII Limited Partnership, Highland Capital Partners VII Limited Partnership, Highland Capital Partners VII-B Limited Partnership and Highland Capital Partners VII-C Limited Partnership have filed a separate Form 4. The Reporting Persons are jointly filing this Form 4 pursuant to Rule 16a-3(j) under the Exchange Act. /s/ Paul Maeder, Authorized Manager of Highland Management Partners VII, LLC, the general partner of Highland Management Partners VII Limited Partnership, the general partner of Highland Entrepreneurs' Fund VII Limited Partnership 2018-05-10 /s/ Paul Maeder, Authorized Manager of Highland Management Partners VI, Inc., the general partner of HEF VI Limited Partnership 2018-05-10