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 December, 2025

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)

Calle Azul 4,

28050 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”), in compliance with the securities market legislation, hereby communicates the following:

OTHER RELEVANT INFORMATION

Further to the notice of inside information of 30 October 2025, with registration number 2966, relating to the execution of a buyback program of own shares of BBVA (the “Buyback Program”), and pursuant to article 5 of Regulation (EU) no. 596/2014 of the European Parliament and of the Council of 16 April 2014 on market abuse, BBVA informs that it has carried out the following transactions over BBVA shares in execution of the Buyback Program between 24 November and 28 November 2025 (both inclusive):

The cash amount of the shares purchased to date as a result of the execution of the Buyback Program amounts to 710,265,440.58 Euros, which, approximately, represents 71.53% of the maximum cash amount of the Buyback Program.

Issuer name: Banco Bilbao Vizcaya Argentaria, S.A. - LEI K8MS7FD7N5Z2WQ51AZ71

ISIN Code of the ordinary shares of BBVA: ES0113211835

Madrid, 1 December 2025

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.