Report of Foreign Issuer (6-k)

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

Report of Foreign Issuer

Pursuant to Rule 13a-16 or 15d-16

of the Securities Exchange Act of 1934

For the month of September, 2019

Commission File Number: 001-12102

YPF Sociedad Anónima

(Exact name of registrant as specified in its charter)

Macacha Güemes 515

C1106BKK Buenos Aires, Argentina

(Address of principal executive office)

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

Form 20-F ☒ 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):

Yes ☐ No ☒

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):

Yes ☐ No ☒

YPF Sociedad Anónima

TABLE OF CONTENTS

ITEM

1 Translation of letter to the Buenos Aires Stock Exchange dated September 2, 2019.

LOGO

TRANSLATION

Buenos Aires, September 2, 2019

To the

Bolsa de Comercio de Buenos Aires

(Buenos Aires Stock Exchange)

Re.: Relevant Fact – DNU No. 601/2019

The purpose of this letter is to comply with the requirements of Article 23 of Chapter VI of the ByMA Listing Regulations.

In that regard, and continuing with our prior communications dated August 16, 2019, we inform you that Presidential Decree No. 601 (the “Decree”) in General Agreement of Ministers, published in the Official Gazette on September 2, 2019, amended Decree No. 566/2019 by providing that:

Until November 13, 2019, deliveries of crude oil in the local market must be invoiced and paid at the agreed-upon price between producing companies and refineries as of August 9, 2019, and by applying a reference exchange rate of Argentinean Ps. 46.69 per U.S. Dollar and reference BRENT price of U.S.$59 per barrel. (Replaced art. 1 of Decree No. 566/2019)

Until November 13, 2019, the maximum price for gasoline and diesel traded by refiners and/or wholesalers and/or retailers, regardless of their quality, whose destined to public supply through fuel pumps (gas stations), shall in no case be greater than the price which was in effect on August 9, 2019. (Replaced art. 2 of Decree No. 566/2019)

The Decree entered into force at the time it was published in the Official Gazette, and shall be applicable to transactions which take place following such time.

A link to the Decree (in Spanish language) is attached: https://www.boletinoficial.gob.ar/detalleAviso/primera/215253/20190902

YPF S.A. is currently analyzing the impact which these measures may have.

Yours faithfully,

Ignacio Rostagno

Market Relations Officer

YPF S.A.

SIGNATURE

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.