On 25 July 2018, a judgment of the Court of Justice of the European Union (CJEU) was issued on whether Bulgaria interest penalty rules in respect of withholding tax under tax treaties violate EU law. The rules generally provide that in order for a reduced withholding tax rate under a treaty to apply, the non-resident must provide proof that it is eligible for the reduced withholding tax. If a reduced withholding tax is applied without proof being provided, an interest penalty will apply from…