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 30, 2015

Concho Resources Inc.

(Exact Name of Registrant as Specified in Its Charter)

Delaware

(State or Other Jurisdiction of Incorporation)

Registrant’s telephone number, including area code: (432) 683-7443

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. below):

Item 8.01 Other Events.

On September 30, 2015, Concho Resources Inc. (the “Company”) filed with the Securities and Exchange Commission a preliminary prospectus supplement pursuant to Rule 424(b) of the Securities Act of 1933, as amended, and announced the launch of an underwritten public offering of common stock in connection therewith. The preliminary prospectus supplement for the public offering contains updated Company risk factor disclosure. Accordingly, the Company is filing information for the purpose of supplementing and updating the risk factor disclosure contained in its prior public filings, including those discussed under the heading “Item 1A. Risk Factors” in its Annual Report on Form 10-K for the year ended December 31, 2014, filed with the Securities and Exchange Commission on February 26, 2015, and in its subsequent Quarterly Reports on Form 10-Q. The updated risk factor is as follows:

Future price declines could result in a reduction in the carrying value of our proved oil and natural gas properties, which could adversely affect our results of operations.

Declines in commodity prices may result in having to make substantial downward adjustments to the value of our estimated proved reserves. If this occurs, or if our estimates of production or economic factors change, accounting rules may require us to write-down, as a non-cash charge to earnings, the carrying value of our proved oil and natural gas properties for impairments. We are required to perform impairment tests on proved assets whenever events or changes in circumstances warrant a review of our proved oil and natural gas properties. To the extent such tests indicate a reduction of the estimated useful life or estimated future cash flows of our oil and natural gas properties, the carrying value may not be recoverable and therefore require a write-down. The primary factors that may affect management’s estimates of future cash flows are (i) commodity future prices, (ii) increases or decreases in production and capital costs, (iii) future reserve adjustments, both positive and negative, to proved reserves and appropriate risk-adjusted probable and possible reserves and (iv) results of future drilling activities. We may incur impairment charges in the future, which could materially adversely affect our results of operations in the period incurred.

Additionally, based on the factors above as of June 30, 2015, we determined that undiscounted future cash flows attributable to a certain depletion group with net book value of approximately $1.9 billion indicated that the carrying amount was expected to be recovered; however, it may be at risk for impairment if management’s estimates of future cash flows decline, including as a result of further declines in projected commodity prices (and the resulting impact of future cash flows) since June 30, 2015. We estimate that, if this depletion group was to become impaired in the current or a future period, we could recognize non-cash impairment in that period in excess of $1.0 billion.

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.