Sec Form 3 Filing - THL Equity Advisors VI (2019), LLC @ Syneos Health, Inc. - 2019-04-30

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

OMB APPROVAL OMB Number: 3235-0287 Expires: November 30, 2011 Estimated average burden hours per response... 0.5

1. Name and Address of Reporting Person THL Equity Advisors VI (2019), LLC 2. Issuer Name and Ticker or Trading Symbol Syneos Health, Inc. [ SYNH] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X __ Director X __ 10% Owner _____ Officer (give title below) _____ Other (specify below) (Last) (First) (Middle) C/O THOMAS H. LEE PARTNERS, L.P., 100 FEDERAL STREET, 35TH FLOOR 3. Date of Earliest Transaction (MM/DD/YY) 04/30/2019 (Street) BOSTON, MA02110 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 Class A Common Stock 5,504,340 ( 2 ) I See footnotes ( 1 ) ( 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 THL Equity Advisors VI (2019), LLC C/O THOMAS H. LEE PARTNERS, L.P. 100 FEDERAL STREET, 35TH FLOOR BOSTON, MA02110 X X Thomas H. Lee Equity Fund VI (2019), L.P. C/O THOMAS H. LEE PARTNERS, L.P. 100 FEDERAL STREET, 35TH FLOOR BOSTON, MA02110 X X THL Fund VI (2019) Coinvestment Partners, L.P. C/O THOMAS H. LEE PARTNERS, L.P. 100 FEDERAL STREET, 35TH FLOOR BOSTON, MA02110 X X Signatures THL Equity Advisors VI (2019), LLCBy: Thomas H. Lee Partners, L.P., its sole memberBy: Thomas H. Lee Advisors, LLC, its general partnerBy: THL Holdco, LLC, its managing member/s/ Charles P. HoldenName: Charles P. HoldenTitle: Managing Director 06/26/2019 Signature of Reporting Person Date

Explanation of Responses:

( 1 )This statement is being filed by the following Reporting Persons: Thomas H. Lee Equity Fund VI (2019), L.P. ("Fund VI 2019 LP"); THL Equity Advisors VI (2019), LLC ("Fund VI 2019 GP"); and THL Fund VI (2019) Coinvestment Partners, L.P. ("Fund VI 2019 Coinvest"). Each of the Reporting Persons disclaims beneficial ownership of all shares of the Issuer for the purposes of Section 16 or for any other purpose, except to the extent of such Reporting Person's pecuniary interest therein. ( 2 )Represents 5,352,591 shares of the Issuer directly owned by Fund VI 2019 LP and 151,749 shares of the Issuer directly owned by Fund VI 2019 Coinvest. ( 3 )THL Holdco, LLC is the managing member of Thomas H. Lee Advisors, LLC, which in turn is the general partner of Thomas H. Lee Partners, L.P., which in turn is the sole member of Fund VI 2019 GP and general partner of THL 2019 Coinvest. Fund VI 2019 GP is the general partner of Fund VI 2019 LP.

Remarks: Exhibit 99.1 (Joint Filer Information) is incorporated herein by reference. This Form 4 is filed by Designated Filer THL Equity Advisors VI (2019), LLC.

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).

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.