A significant error last year caused Citigroup to mistakenly credit a customer account with $81 trillion instead of the intended $280, as reported by the Financial Times.
The error went unnoticed by a payments employee and another staff member before being approved for processing the next day, according to sources cited by the FT. Fortunately, a third employee identified the mistake an hour and a half after processing, leading to the transaction’s reversal, with no funds leaving the bank.
Citi informed the US Federal Reserve and the Office of the Comptroller of the Currency about the “near miss.” If the error had gone unchecked, the transaction would have failed due to its size, as the entire US stock market was valued at only $62 trillion at the end of 2024.
A spokesperson for Citi stated: “Despite the improbability of executing a payment of this size, our detective controls quickly identified the input error between two accounts, and we reversed the entry. Our preventative measures would have also prevented any funds from leaving the bank.
“While there was no impact on the bank or our client, this incident highlights our ongoing efforts to eliminate manual processes and automate controls as part of our transformation.”
In a separate instance in 2022, a similar fat finger error had real-world consequences when a trader mistakenly entered a sell order for a basket of equities valued at $444 billion instead of the intended $58 million. Although Citi’s trading system blocked $225 billion from being processed, $189 billion was sent to a trading algorithm, resulting in the sale of $1.4 billion in equities across European exchanges before the trader canceled the order. This incident led to Citigroup facing a fine of £61.7 million from British regulators.