Washington, D.C. 20549


Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934
or Section 30(h) of the Investment Company Act of 1940
OMB Number: 3235-0104
Estimated average burden
hours per response: 0.5
1. Name and Address of Reporting Person*
Webber Stephen J.

(Last) (First) (Middle)


(City) (State) (Zip)
2. Date of Event Requiring Statement (Month/Day/Year)
3. Issuer Name and Ticker or Trading Symbol
Carbon Black, Inc. [ CBLK ]
4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
Director 10% Owner
X Officer (give title below) Other (specify below)
See Remarks
5. If Amendment, Date of Original Filed (Month/Day/Year)
6. Individual or Joint/Group Filing (Check Applicable Line)
X Form filed by One Reporting Person
Form filed by More than One Reporting Person
Table I - Non-Derivative Securities Beneficially Owned
1. Title of Security (Instr. 4) 2. Amount of Securities Beneficially Owned (Instr. 4) 3. Ownership Form: Direct (D) or Indirect (I) (Instr. 5) 4. Nature of Indirect Beneficial Ownership (Instr. 5)
Table II - Derivative Securities Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 4) 2. Date Exercisable and Expiration Date (Month/Day/Year) 3. Title and Amount of Securities Underlying Derivative Security (Instr. 4) 4. Conversion or Exercise Price of Derivative Security 5. Ownership Form: Direct (D) or Indirect (I) (Instr. 5) 6. Nature of Indirect Beneficial Ownership (Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares
Explanation of Responses:
No Securities are beneficially owned.Title: Executive Vice President, Chief Financial Officer, Principal Accounting Officer, Treasurer and Assistant Secretary
No securities are beneficially owned.
/s/ 03/13/2019
** Signature of Reporting Person Date
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 5 (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).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.

     The undersigned hereby constitutes and appoints each of Eric 
Pyenson and Patrick Morely signing singly, and with full power of 
substitution, the undersigned's true and lawful attorney-in-fact 
(1)  execute for and on behalf of the undersigned, in the 
undersigned's capacity as an officer, director and/or ten percent 
(10%) shareholder of Carbon Black, Inc., a Delaware corporation 
(the "Company"), from time to time the following U.S. Securities 
and Exchange Commission ("SEC") forms: (i) Form ID, including any 
attached or related documents (such as Update Passphrase 
Authentication), to effect the assignment of codes to the 
undersigned to be used in the transmission of information to the 
SEC using the EDGAR System; (ii) Form 3, Initial Statement of 
Beneficial Ownership of Securities, including any attached 
documents; (iii) Form 4, Statement of Changes in Beneficial 
Ownership of Securities, including any attached documents; (iv) 
Form 5, Annual Statement of Beneficial Ownership of Securities in 
accordance with Section 16(a) of the Securities Exchange Act of 
1934, as amended, and the rules thereunder, including any 
attached documents; (v) Schedule 13D; and (vi) amendments of each 
thereof, in accordance with the
 Securities Exchange Act of 1934, 
as amended, and the rules thereunder, including any attached 

(2)   do and perform any and all acts for and on behalf of the 
undersigned which may be necessary or desirable to complete and 
execute any such Form 3, 4 or 5, Schedule 13D or any amendment(s) 
thereto, and timely file such form(s) with the SEC and any 
securities exchange, national association or similar authority; 

(3)   take any other action of any type whatsoever in connection 
with the foregoing which, in the opinion of such attorney-in-
fact, may be of benefit to, in the best interest of, or legally 
required by, the undersigned, it being understood that the 
documents executed by such attorney-in-fact on behalf of the 
undersigned pursuant to this Power of Attorney shall be in such 
form and shall contain such terms and conditions as such 
attorney-in-fact may approve in such attorney-in-fact's 

The undersigned hereby grants to each such attorney-in-fact, 
acting singly, full power and authority to do and perform any and 
every act and thing whatsoever requisite, necessary or proper to 
be done in the exercise of any of the rights and powers herein 
granted, as fully to all intents and purposes as the undersigned 
might or could do if personally present, with full power of 
substitution or revocation, hereby ratifying and confirming all 
that such attorney-in-fact, or such attorney-in-fact's substitute 
or substitutes, shall lawfully do or cause to be done by virtue 
of this power of attorney and the rights and powers herein 
granted.  The undersigned acknowledges that the foregoing 
attorneys-in-fact, in serving in such capacity at the request of 
the undersigned, are not assuming, nor is the Company assuming, 
any of the undersigned's responsibilities to comply with Section 
16 or Regulation 13D-G of the Securities Exchange Act of 1934, as 
amended.  The undersigned hereby agrees to indemnify the 
attorneys-in-fact and the Company from and against any demand, 
damage, loss, cost or expense arising from any false or 
misleading information provided by the undersigned to the 

This Power of Attorney shall remain in full force and effect 
until the undersigned is no longer required to file such forms 
with respect to the undersigned's holdings of and transactions in 
securities issued by the Company, unless earlier revoked by the 
undersigned in a signed writing delivered to the foregoing 

IN WITNESS WHEREOF, the undersigned has caused this Power of 
Attorney to be executed as of March 11, 2019.
/s/ Stephen J. Webber
Stephen J. Webber