Citigroup Inc. almost shifted about $6 billion to a customer’s account by accident after a staffer handling the transfer copied and pasted the account number into a field for the dollar figure.

The near-miss in Citigroup’s wealth-management business magnified the intended amount by more than a thousand times and was detected on the next business day, according to people familiar with the matter. It happened in April, the same month that another part of the bank accidentally credited $81 trillion to a different client.

The wealth division’s error was reported to regulators and, within Citigroup’s offices, provoked audible frustration from Andy Sieg, who had arrived just months earlier to run the unit, according to the people, who asked not to be named discussing private information.

Executives were in the midst of discussions with higher-ups and regulators over how to address what happened when word of the much larger mistake reached them, offering some of the managers a measure of bittersweet relief.

The firm has since set up a companywide tool to help vet large, anomalous payments and transfers, some of the people said.

In a statement, Citigroup said it “promptly identified and corrected this inputting error, which had no impact to the bank or our client. In addition, we have implemented enhanced preventative measures which are consistent with Citi’s continuing efforts to eliminate manual processes and automate controls.”

The incidents highlight Citigroup’s ongoing struggle to improve risk and controls after it was slapped with regulatory penalties and restrictions because of its poor systems. In January, Chief Executive Officer Jane Fraser lowered a key profitability target, in part because the bank needed to spend more money on its “transformation,” a plan that aims to overhaul operations and assuage watchdogs’ concerns.

For panicked wealth executives, the error invoked memories of Citigroup’s notorious Revlon Inc. incident in 2020, when the bank accidentally transferred more than $900 million to creditors of the cosmetics company, some of the people said. The firm recouped the money more than two years later through a lengthy legal battle.

Still, in this case — as with the $81 trillion credit that was first reported by the Financial Times last week — the error was related to an attempted transfer of funds between internal accounts, reducing the risk to the bank.

In the larger case, the mistake was caught about 90 minutes later, according to the FT, and was so big — dwarfing the firm’s total assets — that the funds couldn’t have left. The process at the center of that incident has since been fully automated, according to another person with knowledge of the situation.