Sec Form 4 Filing - Schaffer Paul W. @ Sun BioPharma, Inc. - 2018-05-16

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 Schaffer Paul W. 2. Issuer Name and Ticker or Trading Symbol Sun BioPharma, Inc. [ SNBP] 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) 712 VISTA BLVD #305 3. Date of Earliest Transaction (MM/DD/YY) 05/16/2018 (Street) WACONIA, MN55387 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 05/16/2018 P 5,000 A 899,204 D Common Stock 05/16/2018 C 11,756 A 200,848 I By Paul W. Schaffer Trust

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 Warrant (right to buy) $ 5 05/16/2018 P 5,000 05/16/2018 05/16/2021 Common Stock 5,000 ( 1 ) 5,000 D Convertible Promissory Note $ 10.1 ( 3 ) 05/16/2018 C 50,000 ( 4 ) 03/17/2017 12/01/2018 Common Stock 4,950 $ 50,000 ( 4 ) 0 I By Paul W. Schaffer Trust Warrant (right to buy) $ 5 05/16/2018 C 11,756 05/16/2018 05/16/2021 Common Stock 11,756 ( 2 ) 11,756 I By Paul W. Schaffer Trust

Reporting Owners Reporting Owner Name / Address Relationships Director 10% Owner Officer Other Schaffer Paul W. 712 VISTA BLVD #305 WACONIA, MN55387 X Signatures /s/ Joshua L. Colburn, attorney-in-fact for Paul W. Schaffer 06/14/2018 Signature of Reporting Person Date

Explanation of Responses:

( 1 )Reflects purchase of 5,000 units from the issuer at a price equal to $5.00 per unit. Each unit consisted of one share of common stock and a warrant to purchase an additional share of common stock. ( 2 )Pursuant to the "alternate conversion" under the Convertible Promissory Note, approximately $52,902 of outstanding principal and accrued but unpaid interest converted into 11,756 units at a price equal to $4.50 per unit. Each unit consisted of one share of common stock and a warrant to purchase an additional share of common stock. ( 3 )Originally convertible into issuer common stock at a price of $10.10 per share upon holder's election. Because a "qualified offering" occurred, outstanding principal and accrued but unpaid interest would have automatically converted into common stock at a rate of $3.35 per share or, as elected, into units at a rate equal to a 10% discount to the price paid in the qualified offering. ( 4 )Represents original principal amount.

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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