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 OF THE SECURITIES EXCHANGE ACT OF 1934 For the month June 2022 (Commission File No. 001-35193) Grifols, S.A. 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 Regulatio ...