Sweden v Belgium - EURO 2016 - Group E - Stade de Nice, Nice, France - 22/6/16 - Sweden fans reacts at the end of the match. Reuters/Yves Herman The Swedish government is being forced to refund billions in taxes after Swedes deliberately paid too much as a consequence of the negative interest rates being implemented in the country.

According to data released by the government on Wednesday, Sweden ended 2016 with a budget surplus of 85 billion kroner (£7.6 billion, $9.5 billion), and about half of that was due to individuals and businesses paying more tax than they needed to as a means of actually making money.

"The development of Sweden's central government finances is still affected by excess deposits in tax accounts," a report from the Swedish National Debt Office said.

With interest rates in the country at -0.5%, holding cash in bank accounts and other savings vessels provides little to no return and in many cases actually costs people money.

But thanks to the way Sweden's taxation system is set up, Swedes can earn interest by paying more tax than they need to and leaving it in their taxpayer payment accounts. These accounts pay interest of 0.56%, far in excess of bank interest rates in the country.

This quirk may be a benefit for Swedes trying to save money, but it is set to cost the Swedish government a substantial amount in interest payments. It is discouraging the practice as a result.

"We cannot do anything [further], it is simply a consequence of current interest rates," Marten Bjellerup, the office's head of forecasting, said on Wednesday, according to a report from the Financial Times (where we first noticed Sweden's tax quirk.)

Sweden's tax issues are just another example of the impact that unprecedented negative interest rates are having. Initially launched as an attempt to spur output and wage growth, negative rates have been widely criticised, with many citing their use so far as something of a failure. The central banks implementing negative rates, however, have consistently argued for their efficacy.