Sec Form 4 Filing - DENNER ALEXANDER J @ Bioverativ Inc. - 2017-05-24

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 DENNER ALEXANDER J 2. Issuer Name and Ticker or Trading Symbol Bioverativ Inc. [ BIVV] 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 BIOVERATIV INC., 225 SECOND AVENUE 3. Date of Earliest Transaction (MM/DD/YY) 05/24/2017 (Street) WALTHAM, MA02451 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 05/24/2017 P 340,000 ( 1 ) A $ 54.16 ( 4 ) ( 5 ) 495,000 I See footnotes ( 8 ) ( 11 ) Common Stock 05/25/2017 P 130,000 ( 2 ) A $ 54.9839 ( 4 ) ( 6 ) 625,000 I See footnotes ( 9 ) ( 11 ) Common Stock 05/26/2017 P 450,000 ( 3 ) A $ 57.2114 ( 4 ) ( 7 ) 1,075,000 I See footnotes ( 10 ) ( 11 ) Common Stock 5,001 D

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 DENNER ALEXANDER J C/O BIOVERATIV INC. 225 SECOND AVENUE WALTHAM, MA02451 X Signatures /s/ Alexander Denner 05/26/2017 Signature of Reporting Person Date

Explanation of Responses:

( 1 )On May 24, 2017, each of Sarissa Capital Domestic Fund LP, a Delaware limited partnership ("Sarissa Domestic") and Sarissa Capital Offshore Master Fund LP, a Cayman Islands exempt limited partnership ("Sarissa Offshore" and together with Sarissa Domestic, the "Sarissa Funds"), purchased an aggregate of 295,800 and 44,200 shares, respectively, of common stock of Bioverativ Inc. ( 2 )On May 25, 2017, each of Sarissa Domestic and Sarissa Offshore purchased an aggregate of 113,100 and 16,900 shares, respectively, of common stock of Bioverativ Inc. ( 3 )On May 26, 2017, each of Sarissa Domestic and Sarissa Offshore purchased an aggregate of 391,500 and 58,500 shares, respectively, of common stock of Bioverativ Inc. ( 4 )Full information regarding the number of shares purchased at each separate price will be provided upon request by the SEC staff, the issuer or a security holder of the issuer. ( 5 )This represents the weighted average price for shares purchased at a range between $54.0278 (low) and $54.2631 (high). ( 6 )This represents the weighted average price for shares purchased at a range between $54.9826 (low) and $54.9994 (high). ( 7 )This represents the weighted average price for shares purchased at a range between $57.1471 (low) and $57.5297 (high). ( 8 )Includes (i) 390,871 shares beneficially owned by Sarissa Domestic and (ii) 104,129 shares beneficially owned by Sarissa Offshore. ( 9 )Includes (i) 503,971 shares beneficially owned by Sarissa Domestic and (ii) 121,029 shares beneficially owned by Sarissa Offshore. ( 10 )Includes (i) 895,471 shares beneficially owned by Sarissa Domestic and (ii) 179,529 shares beneficially owned by Sarissa Offshore. ( 11 )Alexander Denner, Ph.D. is the Chief Investment Officer of Sarissa Capital Management LP, a Delaware limited partnership ("Sarissa Capital"), the investment advisor to the Sarissa Funds. By virtue of the foregoing, Dr. Denner may be deemed to indirectly beneficially own (as that term is defined in Rule 13d-3 of the Securities Exchange Act of 1934, as amended) the shares that the Sarissa Funds directly beneficially own. Dr. Denner disclaims beneficial ownership of these shares except to the extent of his pecuniary interest therein.

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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