UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN ISSUER
PURSUANT TO RULE 13a-16 OR 15b-16 OF
THE SECURITIES EXCHANGE ACT OF 1934

For the month of April 2017

Commission File Number 001-35591

GRAÑA Y MONTERO S.A.A.

(Exact name of registrant as specified in its charter)

GRAÑA Y MONTERO GROUP

(Translation of registrant’s name into English)

Republic of Peru

(Jurisdiction of incorporation or organization)

Avenida Paseo de la República 4667, Lima 34,

Surquillo, Lima

Peru

(Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports under cover Form 20-F or Form 40-F:

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1): [ ]

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7): [ ]

Indicate by check mark whether the registrant by furnishing the information contained in this Form is also thereby furnishing the information to the Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934.

If "Yes" is marked, indicate below the file number assigned to the registrant in connection with Rule 12g3-2(b): Not applicable.

On March 28, 2017, we announced as a Reserved Relevant Information Communication, that our Board of Directors had agreed to sell all of our stake in Compañía Operadora de Gas del Amazones S.A.C. (hereinafter “COGA”), in favor of our partners in said company, subject to the negotiation and agreement to be reached by the parties with respect to the terms and conditions of the transaction, to the results of the due diligence process that will be carried out by the potential buyers as part of their evaluation process and to the approval of the Board of Directors of Enagás and to the Investments Committee of the owner of Carmen Corporation.

In this regard, we inform you as a Relevant Information Communication that today, April 24, 2017, we have signed a purchase agreement for all our shares in COGA, which represent 51% of the company’s shareholders, in favor of its partners Enagás and Carmen Corporation.

___________________________
/s/ Claudia Drago Morante
Stock Market Representative
Graña y Montero S.A.A.

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, thereunto duly authorized.

GRAÑA Y MONTERO S.A.A.

By: /s/ CLAUDIA DRAGO MORANTE
Name: Claudia Drago Morante
Title: Stock Market Representative
Date: April 24, 2017