Cornelia Johansson discovered the windfall on Monday, after she logged on to her Internet bank to pay some bills, regional daily Göteborgs-Posten (GP) 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,” Johansson’s boyfriend Daniel Höglund told the daily.
“Something must have gone totally wrong. We waited anxiously for whoever sent the 10 billion to come forward.”
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.”