UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

WASHINGTON, D.C. 20549

FORM 6-K

REPORT OF FOREIGN ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of November, 2014

Commission file number: 1-10110

BANCO BILBAO VIZCAYA ARGENTARIA, S.A.

(Exact name of Registrant as specified in its charter)

BANK BILBAO VIZCAYA ARGENTARIA, S.A.

(Translation of Registrant’s name into English)

Paseo de la Castellana, 81

28046 Madrid

Spain

(Address of principal executive offices)

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  x            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   x

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   x

Banco Bilbao Vizcaya Argentaria, S.A. (BBVA), pursuant to the provisions of the Spanish Securities Market Act, hereby proceeds by means of the present document to notify the following:

RELEVANT INFORMATION

Following the Relevant Information published yesterday in connection with the launch of an accelerated bookbuilding offer process, BBVA announces that it has sold 242,424,244 newly-issued ordinary shares of BBVA to qualified institutional investors at a price of €8.25 per share.

Madrid, November 20, 2014

IMPORTANT INFORMATION

NOT FOR RELEASE, PUBLICATION OR DISTRIBUTION, DIRECTLY OR INDIRECTLY, IN ANY JURISDICTION IN WHICH THE DISTRIBUTION OR RELEASE WOULD BE UNLAWFUL

This announcement is only addressed to, and directed at, persons in member states of the European Economic Area (“EEA”) who are “qualified investors” within the meaning of Article 2(1)(e) of the Prospectus Directive (Directive 2003/71/EC) as amended by the 2010 PD Amending Directive (Directive 2010/73/EU), as and to the extent implemented in the relevant EEA member state, and any relevant implementing measure in the relevant member state.

In addition, in the United Kingdom, this announcement is directed only at, persons (i) who are persons having professional experience in matters relating to investments who fall within the definition of “investment professionals” in Article 19(5) of The Financial Services and Markets Act 2000 (Financial Promotion) Order 2005, as amended (the “Order”), or (ii) persons who are high net worth entities falling within Article 49(2)(a) to (d) of the Order, and other persons to whom it may lawfully be communicated (“relevant persons”). Under no circumstances should persons who are not relevant persons rely or act upon the contents of this announcement. Any investment or investment activity to which this announcement relates in the United Kingdom is available only to, and will be engaged only with, relevant persons.

These written materials do not constitute an offer to sell, or a solicitation of offers to purchase or subscribe for, securities in the United States. The securities referred to herein have not been, and will not be, registered under the U.S. Securities Act of 1933, as amended, and may not be offered or sold in the United States absent registration or an applicable exemption from registration requirements. There is no intention to register any portion of the offering in the United States or to conduct a public offering of securities in the United States. No money, securities or other consideration from any person is being solicited and, if sent in response to the information contained in these written materials, will not be accepted.

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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.

Date: November 20, 2014

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