ANTERO MIDSTREAM PARTNERS LP (NYSE:AM) Files An 8-K Regulation FD Disclosure
Item 7.01 Regulation FD Disclosure.

On February14, 2019, Antero Midstream Partners LP (“Antero Midstream”) and Antero Midstream GP LP (“AMGP”) updated their monthly investor presentation. The updated investor presentation may be viewed on Antero Midstream’s website at www.anteromidstream.com, and a copy of the investor presentation is included as Exhibit99.1 to this Current Report on Form8-K and is incorporated into this Item 7.01 by reference

Also on February14, 2019, Antero Midstream held a conference call with analysts and investors to discuss fourth quarter and full year 2018 results. On the call, certain matters relating to the previously announced business combination transaction between Antero Midstream and AMGP were discussed. Atranscriptof the conference call is included as Exhibit99.2 to this Current Report on Form8-K, and the full text of suchtranscriptis incorporated herein by reference. A copy of the presentation given during the conference call is included as Exhibit99.3 to this Current Report on Form8-K and is incorporated into this Item 7.01 by reference.

The information furnished in this Item 7.01 (including the exhibits) shall not be deemed “filed” for purposes of Section18 of the Securities Exchange Act of 1934, as amended, or otherwise subject to the liabilities of that section, nor shall such information be deemed incorporated by reference in any filing under the Securities Act of 1933, as amended, regardless of any general incorporation language in such filing, except as shall be expressly set forth by specific reference in such filing.

Item 8.01 Other Events.

To the extent required by law, the information in Item 7.01 of this Form8-K is incorporated into this Item 8.01.

NO OFFER OR SOLICITATION

The exhibits attached hereto include a discussion of the previously announced transaction between Antero Midstream and AMGP and certain of their affiliates (the “Transaction”). This communication is for informational purposes only and does not constitute an offer to sell or the solicitation of an offer to buy any securities or a solicitation of any vote or approval, in any jurisdiction, to the Transaction or otherwise, nor shall there be any sale, issuance, exchange or transfer of the securities referred to in this document in any jurisdiction in contravention of applicable law. No offer of securities shall be made except by means of a prospectus meeting the requirements of Section10 of Securities Act of 1933, as amended.

ADDITIONAL INFORMATION AND WHERE TO FIND IT

In connection with the Transaction, AMGP has filed with the U.S. Securities and Exchange Commission (the “SEC”) a registration statement on FormS-4, that includes a joint proxy statement of Antero Midstream and AMGP and a prospectus of AMGP. The transaction will be submitted to Antero Midstream’s unitholders and AMGP’s shareholders for their consideration. Antero Midstream and AMGP may also file other documents with the SEC regarding the transaction. The registration statement on FormS-4 became effective on January30, 2019, and the definitive joint proxy statement/prospectus is being delivered to Antero Midstream unitholders and AMGP shareholders of record as of January11, 2019. This document is not a substitute for the registration statement and joint proxy statement/prospectus that has been filed with the SEC or any other documents that AMGP or Antero Midstream may file with the SEC or send to shareholders of AMGP or unitholders of Antero Midstream in connection with the transaction. INVESTORS AND SECURITY HOLDERS OF ANTERO MIDSTREAM AND AMGP ARE URGED TO READ THE REGISTRATION STATEMENT AND THE JOINT PROXY STATEMENT/PROSPECTUS REGARDING THE TRANSACTION AND ALL OTHER RELEVANT DOCUMENTS THAT ARE FILED OR WILL BE FILED WITH THE SEC, AS WELL AS ANY AMENDMENTS OR SUPPLEMENTS TO THESE DOCUMENTS, CAREFULLY AND IN THEIR ENTIRETY BECAUSE THEY WILL CONTAIN IMPORTANT INFORMATION ABOUT THE TRANSACTION AND RELATED MATTERS.

Investors and security holders are able to obtain free copies of the registration statement and the joint proxy statement/prospectus and all other documents filed or that will be filed with the SEC by AMGP or Antero Midstream through the website maintained by the SEC at http://www.sec.gov. Copies of documents filed with the SEC by Antero Midstream will be made available free of charge on Antero Midstream’s website at http://investors.anteromidstream.com/investor-relations/AM, under the heading “SEC Filings,” or by directing a