Supreme Court overturns LIBOR manipulation convictions in Hayes and Palombo appeals

The Supreme Court has allowed the appeals of Tom Hayes and Carlo Palombo, ruling that fundamental misdirections to juries in their LIBOR manipulation trials rendered their convictions unsafe. The judgement, delivered on 23 July 2025, represents a significant development in financial fraud prosecutions and jury instruction protocols.

Case background and original convictions

Hayes received a 14-year sentence in 2015 (later reduced to 11 years) for conspiracy to defraud through LIBOR manipulation, whilst Palombo was sentenced to four years in 2018 for similar offences involving EURIBOR. Both convictions centred on allegations that the defendants submitted false rates to benefit their trading positions, with prosecutors arguing that considerations of trading advantage inherently compromised the integrity of their submissions.

The Court of Appeal had previously upheld both convictions, rejecting arguments that trial judges had misdirected juries regarding the requirement for submissions to constitute genuine assessments of borrowing rates.

Supreme Court's analysis

Lord Leggatt, delivering the Court's opinion, identified critical flaws in the original jury directions. The judgement established that submissions influenced by trading considerations cannot be deemed dishonest per se—dishonesty must be determined by reference to the submitter's genuine beliefs about the rate's accuracy.

The Court found that trial judges had erroneously treated the interpretation of LIBOR and EURIBOR definitions as purely matters of law, thereby removing essential factual determinations from the jury's consideration. This approach fundamentally obscured the central question of the defendants' subjective intent when making rate submissions.

The Supreme Court emphasised that whilst legal definitions carry significant weight, the factual inquiry into defendants' state of mind must remain within the jury's province. The original directions effectively prevented juries from properly assessing whether Hayes and Palombo genuinely believed their submissions to be accurate, regardless of any incidental trading benefits.

Implications for financial fraud prosecutions

The judgement highlights the complex intersection between regulatory definitions and criminal culpability in financial markets. The Court's analysis suggests that regulatory frameworks designed for market oversight may require careful adaptation when applied in criminal proceedings.

The ruling underscores the critical importance of preserving the distinction between legal interpretation and factual determination in jury trials. By conflating these elements, the original trials compromised the defendants' right to have their subjective intent properly assessed by the jury.

The Supreme Court's decision also raises questions about the prosecution strategy in similar cases, where regulatory non-compliance has been treated as equivalent to criminal dishonesty without adequate consideration of the defendant's mental state.

Broader significance

This judgement may prompt a reassessment of how jury directions are formulated in complex financial fraud cases. The Court's emphasis on subjective intent over regulatory interpretation suggests that future prosecutions will need to focus more precisely on defendants' actual knowledge and beliefs rather than technical breaches of regulatory definitions.

The decision also reflects ongoing tensions between the need for robust financial regulation and the requirements of criminal law, particularly regarding the mental elements necessary for fraud convictions. The Supreme Court's intervention serves as a reminder that criminal liability cannot be established solely through regulatory non-compliance without proper consideration of the defendant's subjective culpability.

The allowed appeals may result in the convictions being quashed, marking a significant moment in the ongoing legal reckoning with post-financial crisis prosecutions.