Over four years ago, a former IT employee of HSBC in Switzerland copied and leaked information on the balances of 106,458 customers between 2006 and 2007. The value of the balances totalled 666 billion kroner.

Of those customers, 329 Danes were hiding 4.8 billion kroner in a Swiss HSBC, reports Politiken.

In 2009, French tax authorities got their hands on the list and immediately began investigating potential tax evasion and money laundering cases. A year later, a number of other countries followed France's tactic.

Denmark did not. And hasn't still. But that is quickly changing.

”Frankly it is quite inexplicable that you would choose not to gather data at a time when it was made available to other countries,” the tax minister, Benny Engelbrecht, told Politiken. ”It would be the most natural thing to do in the world.”

READ MORE: New rules to avoid tax evasion

Time running out
Engelbrecht, who took office in September 2014, was not aware of the leaked list until Politiken gained access to the HSBC list and began investigating the story. He has ordered the tax department to immediately get the list extradited from France.

The investigation, however, will have to move quickly as the statute of limitations on taxing, fining or imprisoning tax evaders is ten years from when deposits are made. And in this case, it was eight to nine years ago.

”There is a significant risk that the Danish authorities' delayed reaction will cost tax revenues because the requirements will become outdated,” a tax lawyer, Torben Bagge, told Politiken.