Sec Form 3 Filing - Blackstone Holdings II L.P. @ Forty Seven, Inc. - 2019-01-04

FORM 3 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 Blackstone Holdings II L.P. 2. Issuer Name and Ticker or Trading Symbol Forty Seven, Inc. [ FTSV] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O THE BLACKSTONE GROUP L.P., 345 PARK AVENUE 3. Date of Earliest Transaction (MM/DD/YY) 01/04/2019 (Street) NEW YORK, NY10154 4. If Amendment, Date Original Filed (MM/DD/YY) 6. Individual or Joint/Group Filing (Check Applicable Line) _____ Form filed by One Reporting Person __ X __ 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 3,816,951 I See Footnotes ( 1 ) ( 2 ) ( 3 )

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 Blackstone Holdings II L.P. C/O THE BLACKSTONE GROUP L.P. 345 PARK AVENUE NEW YORK, NY10154 X Blackstone Clarus III L.L.C. C/O THE BLACKSTONE GROUP L.P. 345 PARK AVENUE NEW YORK, NY10154 X Blackstone Holdings I/II GP Inc C/O THE BLACKSTONE GROUP L.P. 345 PARK AVENUE NEW YORK, NY10154 X Blackstone Group L.P. 345 PARK AVENUE NEW YORK, NY10154 X Blackstone Group Management L.L.C. C/O THE BLACKSTONE GROUP L.P. 345 PARK AVENUE NEW YORK, NY10154 X SCHWARZMAN STEPHEN A C/O THE BLACKSTONE GROUP L.P. 345 PARK AVENUE NEW YORK, NY10154 X Signatures BLACKSTONE CLARUS III L.L.C., By: Blackstone Holdings II L.P., its managing member, By: Blackstone Holdings I/II GP Inc., its general partner, By: /s/ John G. Finley, Name: John G. Finley, Title: Chief Legal Officer 01/10/2019 Signature of Reporting Person Date BLACKSTONE HOLDINGS II L.P., By: Blackstone Holdings I/II GP Inc., its general partner, By: /s/ John G. Finley, Name: John G. Finley, Title: Chief Legal Officer 01/10/2019 Signature of Reporting Person Date BLACKSTONE HOLDINGS I/II GP INC., By: /s/ John G. Finley, Name: John G. Finley, Title: Chief Legal Officer 01/10/2019 Signature of Reporting Person Date THE BLACKSTONE GROUP L.P., By: Blackstone Group Management L.L.C., its general partner, By: /s/ John G. Finley, Name: John G. Finley, Title: Chief Legal Officer 01/10/2019 Signature of Reporting Person Date BLACKSTONE GROUP MANAGEMENT L.L.C., By: /s/ John G. Finley, Name: John G. Finley, Title: Chief Legal Officer 01/10/2019 Signature of Reporting Person Date /s/ Stephen A. Schwarzman 01/10/2019 Signature of Reporting Person Date

Explanation of Responses:

( 1 )These securities are held directly by Clarus Lifesciences III, L.P. ("Clarus III"). Clarus Ventures III GP, L.P. ("Clarus III GP") is the sole general partner of Clarus III. Blackstone Clarus III L.L.C. is the sole general partner of Clarus GP. The sole member of Blackstone Clarus III L.L.C. is Blackstone Holdings II L.P. The sole general partner of Blackstone Holdings II L.P. is Blackstone Holdings I/II GP Inc. The controlling shareholder of Blackstone Holdings I/II GP Inc. is The Blackstone Group L.P. The sole general partner of The Blackstone Group L.P. is Blackstone Group Management L.L.C. Blackstone Group Management L.L.C. is wholly-owned by Blackstone's senior managing directors and controlled by its founder, Stephen A. Schwarzman. ( 2 )Information with respect to each of the Reporting Persons is given solely by such Reporting Person, and no Reporting Person has responsibility for the accuracy or completeness of information supplied by another Reporting Person. ( 3 )Each of such Reporting Persons may be deemed to beneficially own the shares beneficially owned by Clarus III, but each disclaims beneficial ownership of such shares, except to the extent of such Reporting Person's pecuniary interest therein. The filing of this statement shall not be deemed to be an admission that, for purposes of Section 16 of the Securities Exchange Act of 1934 or otherwise, the Reporting Persons are the beneficial owners of any securities reported herein.

Remarks: This Form 3 is being filed in connection with the acquisition by The Blackstone Group L.P. and certain of its affiliates ("Blackstone") of Clarus Ventures, LLC and certain of its affiliates (collectively, "Clarus"). On January 4, 2019, Blackstone integrated the Clarus business into Blackstone (the "Clarus Integration"). As a result of such integration, Blackstone may be deemed to have become the beneficial owner of the securities beneficially owned by Clarus, including the securities of the Issuer.

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).

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