A Swedish woman got the shock of her life when she found $US1.13 billion ($1.76 billion) more than expected in her bank account.
Cornelia Johansson discovered the windfall after she logged on to her account via the internet to pay some bills, regional daily Goeteborgs-Posten said in its online edition.
"The balance was more than 10 billion kronor. It said the amount had been deposited as a correction for a credit card purchase," Ms Johansson's boyfriend Daniel Hoeglund told the newspaper.
On Tuesday morning, the money was still credited to her account, but a few hours later it was gone, as mysteriously as it had arrived.
A press spokeswoman for Nordea bank, the largest bank in the Nordic region, later explained the mystery as "a technical mistake made by a company".