Sec Form 4 Filing - Stahl Maria D @ TETRAPHASE PHARMACEUTICALS INC - 2019-01-17

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 Stahl Maria D 2. Issuer Name and Ticker or Trading Symbol TETRAPHASE PHARMACEUTICALS INC [ TTPH] 5. Relationship of Reporting Person(s) to Issuer (Check all applicable) _____ Director _____ 10% Owner X __ Officer (give title below) _____ Other (specify below) SVP and General Counsel (Last) (First) (Middle) C/OTETRAPHASE PHARMACEUTICALS, INC., 480 ARSENAL STREET, SUITE 110 3. Date of Earliest Transaction (MM/DD/YY) 01/17/2019 (Street) WATERTOWN, MA02472 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 01/06/2019 A V 18,698 A 23,698 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 Restricted Stock Units ( 2 ) 01/17/2019 A 40,000 ( 3 ) ( 3 ) Common Stock 40,000 $ 0 40,000 D Restricted Stock Units ( 2 ) 01/17/2019 A 140,000 ( 4 ) ( 4 ) Common Stock 140,000 $ 0 140,000 D

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Stahl Maria D C/OTETRAPHASE PHARMACEUTICALS, INC. 480 ARSENAL STREET, SUITE 110 WATERTOWN, MA02472 SVP and General Counsel Signatures /s/Maria Stahl 01/18/2019 Signature of Reporting Person Date

Explanation of Responses:

( 1 )On January 6, 2016, the Reporting person was granted 30,000 restricted stock units ("RSUs")( the "2016 RSU grant") that were previously reported on Table II Of Form 4, which form was filed with the Securities and Exchange Commission on January 8, 2016. Of the 2016 RSU grant, an aggregate of 30,000 shares have vested of which 11,302 shares were withheld by the Issuer to satisfy the reporting person's tax withholding obligations in connection with the delivery of the conversion of the RSUs into common stock on respective vesting dates. The total number of shares beneficially owned by the reporting person consists of the aggregate 18,698 RSUs converted into shares of common stock of the Issuer on the respective vesting dates and an additional 5,000 shares owned indirectly. ( 2 )Each restricted stock unit represents a contingent right to receive one share of common stock of Tetraphase Pharmaceuticals, Inc. for no consideration. ( 3 )These restricted stock units shall be eligible to vest upon achievement of certain performance conditions and, if such conditions are met, shall vest on various dates beginning no earlier than March 1, 2020 and ending no later than on March 1, 2022. ( 4 )The restricted stock units vest in three equal installments on each of January 17, 2020, January 17, 2021 and January 17, 2022.

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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