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

Date of Report (Date of earliest event reported): September 27, 2018

ROSEHILL RESOURCES INC.

(Exact name of registrant as specified in its charter)

16200 Park Row, Suite 300

Houston, Texas, 77084

(Address of principal executive offices, including zip code)

(281) 675-3400

(Registrants’ telephone number, including area code)

(Former name or former address, if changed since last report)

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:

Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§240.12b-2 of this chapter).

☒    Emerging growth company

☐    If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.

On September 27, 2018, Rosehill Resources Inc., a Delaware corporation (the “Company”), entered into an underwriting agreement (the “Underwriting Agreement”) with Citigroup Global Markets Inc., as representative of the several underwriters named therein (the “Underwriters”), relating to the offer and sale of the Company’s Class A common stock, par value $0.0001 per share (the “Class A Common Stock”). The Underwriting Agreement provides for the offer and sale (the “Offering”) of an aggregate of 6,150,000 shares of Class A Common Stock at a price to the public of $6.10 per share ($5.795 per share net of underwriting discounts and commissions). Pursuant to the Underwriting Agreement, the Company has granted the Underwriters a 30-day option (the “Option”) to purchase up to an additional 922,500 shares of Class A Common Stock, solely to cover over-allotments, if any. The material terms of the Offering are described in the prospectus, dated September 27, 2018 (the “Prospectus”), filed by the Company with the Securities and Exchange Commission (the “Commission”) on October 1, 2018, pursuant to Rule 424(b) under the Securities Act of 1933, as amended (the “Securities Act”). The Offering is registered with the Commission pursuant to a Registration Statement on Form S-1, as amended (File No. 333-223041), initially filed by the Company on February 14, 2018.

The Underwriting Agreement contains customary representations and warranties, agreements and obligations, closing conditions and termination provisions. The Company has agreed to indemnify the Underwriters against certain liabilities, including liabilities under the Securities Act, and to contribute to payments the Underwriters may be required to make because of any of those liabilities.

The Company expects the Offering to close on October 2, 2018, subject to customary closing conditions. The Company expects to receive approximately $34.8 million (or approximately $40.2 million if the Option is exercised in full) of net proceeds from the Offering, after deducting underwriting discounts and estimated offering expenses. As described in the Prospectus, the Company intends to contribute all of the net proceeds of the Offering to Rosehill Operating Company, LLC (“Rosehill Operating”) in exchange for a number of units in Rosehill Operating equal to the number of shares of Class A Common Stock issued by the Company in the Offering. Rosehill Operating intends to use the net proceeds from the Offering to finance its development plan and for general corporate purposes, including to fund potential future acquisitions.

The Underwriters are full-service financial institutions engaged in various activities, which may include securities trading, commercial and investment banking, financial advisory, investment management, principal investment, hedging, financing and brokerage activities. The Underwriters and their respective affiliates have in the past performed commercial banking, investment banking and advisory services for the Company from time to time for which they have received customary fees and reimbursement of expenses and may, from time to time, engage in transactions with and perform services for the Company in the ordinary course of their business for which they may receive customary fees and reimbursement of expenses. In the ordinary course of their various business activities, the Underwriters and their respective affiliates may make or hold a broad array of investments and actively trade debt and equity securities (or related derivative securities) and financial instruments (which may include bank loans and/or credit default swaps) for their own account and for the accounts of their customers and may at any time hold long and short positions in such securities and instruments. Such investments and securities activities may involve securities and/or instruments of the Company or its affiliates. The Underwriters and their affiliates may also make investment recommendations and/or publish or express independent research views in respect of such securities or financial instruments and may hold, or recommend to clients that they acquire, long and/or short positions in such securities and instruments.

The foregoing description of the Underwriting Agreement is qualified in its entirety by reference to the full text of the Underwriting Agreement, which is attached as Exhibit 1.1 to this Current Report on Form 8-K and incorporated in this Item 1.01 by reference.

(d) Exhibits

SIGNATURES

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