UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2):

☐ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

☐ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

☐ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

☐ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

On February 17, 2017 and March 3, 2017, Sun BioPharma, Inc. (the “Company”) entered into Note Purchase Agreements (the “Purchase Agreements”) with the investors named therein (the “Investors”) and closed the transactions governed thereby. Pursuant to the February 17, 2017 and March 3, 2017 Purchase Agreements, the Company issued to the Investors $235,000 and $1,260,000, respectively, in original principal amount of unsecured convertible promissory notes (the “Notes”) to accredited investors for a total of $1,495,000 in gross proceeds.

Amounts borrowed under the Notes are scheduled to mature on December 1, 2018 and will bear interest at a rate of 5.0% per annum. Principal and interest on the Notes are payable at maturity. The Company may prepay the Notes in whole or in part at any time without penalty or premium. The Notes may be converted into shares of common stock or other securities of the Company upon certain triggering events as described in the Notes, including certain transactions and upon the request of a holder of any Note. Upon the occurrence of certain events of default, the Notes require the Company to repay the unpaid principal amount of the Notes and any unpaid accrued interest. The Company expects to use the net proceeds from the sales of the Notes for working capital and general corporate purposes.

The foregoing descriptions of the Purchase Agreement and the Notes are summaries and qualified by reference to the text of such documents, which is attached hereto as Exhibits 10.1 and 10.2, respectively, and incorporated herein by reference.

The information disclosed in Item 1.01 is incorporated by reference into this Item. 

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this Current Report to be signed on its behalf by the undersigned hereunto duly authorized.

Index to Exhibits

2