Exhibit 2.3

Execution Version

AMENDMENT NO. 1

TO AGREEMENT AND PLAN OF MERGER

THIS AMENDMENT NO. 1 to Agreement and Plan of Merger (this “Amendment”), dated as of January 26, 2015, is made by and among HEYCO Energy Group, Inc., a Delaware corporation (the “Sole Shareholder”), Harvey E. Yates Company, a New Mexico corporation (the “Company”), Matador Resources Company, a Texas corporation (“Parent”), and MRC Delaware Resources, LLC, a Texas limited liability company and direct wholly owned subsidiary of Parent (“MRC Delaware”).

WHEREAS, the Sole Shareholder, the Company and Parent have entered into that certain Agreement and Plan of Merger, dated as of January 19, 2015 (the “Merger Agreement”);

WHEREAS, the entity referred to in the Merger Agreement as “MRC Delaware Company, LLC” was not formed as of the date of the Merger Agreement;

WHEREAS, pursuant to Section 13.1 of the Merger Agreement, the parties desire to amend the Merger Agreement in the manner set forth below;

WHEREAS, MRC Delaware is executing this Amendment for the purpose of becoming a party to the Merger Agreement; and

WHEREAS, all capitalized terms used herein without definition shall have the respective meanings given to them in the Merger Agreement;

NOW THEREFORE, in consideration of the premises and mutual covenants and agreements contained herein and in the Merger Agreement, and other good and valuable consideration, the receipt and sufficiency of which are hereby acknowledged, the parties hereto agree as follows:

1.The Merger Agreement is hereby amended such that (a) all references in the Merger Agreement to “MRC Delaware Company, LLC” shall be deleted and replaced with “MRC Delaware Resources, LLC” and (b) all references in the Merger Agreement to “Merger Subsidiary” shall be deemed to refer to MRC Delaware, which is deemed to be a party to the Merger Agreement as of the date hereof.

2.The parties acknowledge that (a) all representations and warranties made by Merger Subsidiary in the Merger Agreement and (b) all representations and warranties made by Parent in the Merger Agreement to the extent they relate to Merger Subsidiary, in each case shall be deemed to be made as of the date hereof instead of the date of the Merger Agreement.

3.The parties acknowledge that, except as specifically amended hereby, all terms and conditions of the Merger Agreement remain unchanged and that the Merger Agreement, as amended hereby, is in full force and effect and confirmed in all respects.

4.The following provisions of the Merger Agreement are hereby incorporated into and specifically made applicable to this Amendment (provided, that, in construing such incorporated provisions, any reference to “this Agreement” shall be deemed to refer to this Amendment):

Section 13.1    Amendment and Modification

Section 13.2    Severability

Section 13.6    Counterparts

Section 13.11    Governing Law

[SIGNATURE PAGE FOLLOWS]

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IN WITNESS WHEREOF, the undersigned have caused this Amendment to be signed, all as of the date first written above.

SOLE SHAREHOLDER:

HEYCO ENERGY GROUP, INC.

By:    /s/ George M. Yates______________

Name:     George M. Yates

Title:     President

COMPANY:

HARVEY E. YATES COMPANY

By:    /s/ George M. Yates______________

Name:     George M. Yates

Title:     President

PARENT:

MATADOR RESOURCES COMPANY

By:     /s/ Joseph Wm. Foran____________

Name:     Joseph Wm. Foran

Title: Chairman and Chief Executive Officer

MERGER SUBSIDIARY:

MRC DELAWARE RESOURCES, LLC

By:     /s/ Joseph Wm. Foran____________

Name:     Joseph Wm. Foran

Title: Chairman and Chief Executive Officer

SIGNATURE PAGE TO

AMENDMENT NO. 1 TO

AGREEMENT AND PLAN OF MERGER