Sec Form 4 Filing - CIRINO MARIA @ Carbon Black, Inc. - 2018-05-09

FORM 4 Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940

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1. Name and Address of Reporting Person CIRINO MARIA 2. Issuer Name and Ticker or Trading Symbol Carbon Black, Inc. [ CBLK] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director _____ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O POINT 406 VENTURES, 470 ATLANTIC AVENUE, 12TH FLOOR 3. Date of Earliest Transaction (MM/DD/YY) 05/09/2018 (Street) BOSTON, MA02210 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) __ X __ Form filed by One Reporting Person _____ Form filed by More than One Reporting Person (City) (State) (Zip)

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned 1.Title of Security (Instr. 3) 2. Transaction Date (MM/DD/YY) 2A. Deemed Execution Date, if any (MM/DD/YY) 3. Transaction Code (Instr. 8) 4. Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5) 5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4) 6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4) 7. Nature of Indirect Beneficial Ownership (Instr. 4) Code V Amount (A) or (D) Price Common Stock 05/09/2018 A 6,007 ( 1 ) A $ 0 31,007 D Common Stock 3,000,833 I By Point 406 Ventures I, L.P. ( 2 ) Common Stock 14,426 I By Point 406 Ventures I-A, L.P. ( 3 ) Common Stock 939,526 I By 1941 Co-Invest, LLC ( 4 ) Common Stock 480,750 I By B941, LLC ( 5 )

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned ( e.g. , puts, calls, warrants, options, convertible securities) 1. Title of Derivative Security (Instr. 3) 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (MM/DD/YY) 3A. Deemed Execution Date, if any (MM/DD/YY) 4. Transaction Code (Instr. 8) 5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4, and 5) 6. Date Exercisable and Expiration Date (MM/DD/YY) 7. Title and Amount of Underlying Securities (Instr. 3 and 4) 8. Price of Derivative Security (Instr. 5) 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4) 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I) (Instr. 4) 11. Nature of Indirect Beneficial Ownership (Instr. 4) Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other CIRINO MARIA C/O POINT 406 VENTURES 470 ATLANTIC AVENUE, 12TH FLOOR BOSTON, MA02210 X Signatures /s/ Eric Pyenson, as attorney-in-fact 08/06/2018 Signature of Reporting Person Date

Explanation of Responses:

( 1 )The shares were acquired pursuant to a restricted stock unit award under the 2018 Stock Option and Incentive Plan. Each restricted stock unit represents a contingent right to receive one share of Carbon Black, Inc. common stock. The restricted stock units vest on the earlier of (i) the first anniversary of the vesting commencement date, May 9, 2019 or (ii) the next annual meeting of the Carbon Black Inc.'s shareholders, subject to a continuous service relationship through such date. ( 2 )The shares are held directly by Point 406 Ventures I, L.P. ("Point 406 Ventures I"). The general partner of Point 406 Ventures I is .406 Ventures I GP, L.P. (".406 Ventures I GP"). The general partner of .406 Ventures I GP is .406 Ventures I GP, LLC. Ms. Cirino is a Managing Partner of .406 Ventures I GP, LLC and disclaims Section 16 beneficial ownership of all shares except to the extent of her pecuniary interest, if any, therein. This report shall not be deemed to be an admission that Ms. Cirino is the beneficial owner of such securities for purposes of Section 16 or for any other purpose. ( 3 )The shares are held directly by Point 406 Ventures I-A, L.P. ("Point 406 Ventures I-A"). The general partner of Point 406 Ventures I-A is .406 Ventures I GP. Ms. Cirino disclaims beneficial ownership of all shares except to the extent of her pecuniary interest, if any, therein. This report shall not be deemed to be an admission that Ms. Cirino is the beneficial owner of such securities for purposes of Section 16 or for any other purpose. ( 4 )The shares are held directly by 1941 Co-Invest, LLC. ("1941 Co-Invest"). The general partner of 1941 Co-Invest is .406 Ventures I GP. Ms. Cirino disclaims beneficial ownership of all shares except to the extent of her pecuniary interest, if any, therein. This report shall not be deemed to be an admission that Ms. Cirino is the beneficial owner of such securities for purposes of Section 16 or for any other purpose. ( 5 )The shares are held directly by B941, LLC ("B941"). The general partner of B941 is 406 Ventures I GP. Ms. Cirino disclaims beneficial ownership of all shares except to the extent of her pecuniary interest, if any, therein. This report shall not be deemed to be an admission that Ms. Cirino is the beneficial owner of such securities for purposes of Section 16 or for any other purpose.

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 4(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).

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