Mistakes happen, but some errors are bigger than others. Citigroup recently made headlines after mistakenly crediting a customer’s account with a staggering $81 trillion instead of the intended $280.

The error occurred in April 2024 when a payment employee processed the wrong amount. A second worker also missed the mistake, allowing the transaction to go through the next day. It wasn’t until an hour and a half later that a third employee spotted the issue.

Fortunately, the bank acted quickly and reversed the transaction within a few hours. No money left the bank, and the situation was reported to financial regulators, including the Federal Reserve and the Office of the Comptroller of the Currency.

A spokesperson for Citigroup assured that their security systems quickly identified the mistake. Even if the error had gone unnoticed, preventative controls would have stopped any funds from actually leaving the bank. They also confirmed that neither the customer nor the bank suffered any losses.

This isn’t the first time Citigroup has faced large transaction mistakes. In 2024 alone, there were 10 near-misses where errors of $1 billion or more almost went through. However, this was still an improvement from 13 similar incidents in the previous year.

Although Citigroup was able to catch the mistake in time, this incident highlights how important strong banking controls are. Financial institutions process millions of transactions daily, and even a small oversight can lead to major financial risks.

Banks continue to improve their systems, but human errors still happen. This case serves as a reminder of the need for constant monitoring and strict security measures in the banking industry.