IRPH clauses and consumer protection: transparency thresholds and imbalance standard after judgments 1590/2025 and 1591/2025

Abstract

This article examines the Spanish Supreme Court’s Plenary Judgments 1590/2025 and 1591/2025, 11 November 2025, as the Court’s first pronouncements after the CJEU judgment of 12 December 2024, case C-300/23, in litigation concerning IRPH-linked variable-rate mortgage clauses. In Judgment 1590/2025, the Supreme Court sets out and applies criteria for assessing whether the clause meets the transparency requirement, and it ends the review after finding transparency on the facts. In Judgment 1591/2025, taking the lack of transparency found by the lower courts as a starting point, the Court develops the unfairness test under Article 3(1) of Directive 93/13 and specifies comparative benchmarks to assess any significant imbalance at the time of contracting, adding a “very obvious disproportionality” threshold. The analysis highlights two main tensions. First, transparency may be upheld through references to regulatory texts and through merely theoretical public accessibility, and mandatory enhanced pre-contractual duties may be treated as replaceable by other, insufficiently defined sources of information. Second, imbalance is largely assessed through price comparisons and an indeterminate threshold, which may affect legal certainty and the effectiveness of consumer protection.