The incident, which occurred in April 2024, involved a payment intended to be $280, but was mistakenly entered with numerous extra zeros. Despite the magnitude of the error, no funds left the bank, and the transaction was reversed within hours.

The blunder, missed by multiple employees, was only detected after a balance discrepancy was noticed. Citi disclosed the “near miss” to US regulators. This incident comes as Citi faces scrutiny following a previous $900 million (c. £714m) error involving Revlon, which led to significant fines and regulatory orders, Financial Times reports.

Citi reported ten “near misses” exceeding $1bn (c. £800m) last year, a slight decrease from the previous year. These incidents, where incorrect amounts are processed but ultimately recovered, are not typically publicly reported. However, former regulators suggest such large-scale errors are unusual.

The recent $81 trillion error was attributed to a manual input mistake and a cumbersome backup system. This system, used after a sanctions screening issue, pre-populated the amount field with 15 zeros, which were not deleted. Citi maintains its “detective controls” prevented funds from leaving the bank and emphasises its commitment to automating controls. However, the incident underscores the challenges Citi faces in resolving its operational issues, despite CEO Jane Fraser’s prioritisation of regulatory compliance.