News of corporations taking advantage of tax loopholes to avoid paying their fair share toward the cost of government continues to flow in. Usually, closing these loopholes requires legislative action by a divided Congress, but there’s one $10 billion a year loophole that can be closed with a Treasury Department regulation.

On Tuesday, the Irish government announced plans to close a major tax loophole that had allowed Apple to avoid paying $40 billion in taxes.

The Irish tax loophole allowed firms to shelter profits by using “ghost companies.” These so-called “ghost companies” do not declare residency in any country, thereby avoiding paying taxes to any nation.