Puerto Rico's Treasury Department has issued Administrative Determination (AD) No. 21-05 of 11 May 2021, which provides new guidance regarding the general 51% disallowance of deductions for cross-border expenses incurred with related persons not engaged in trade or business in Puerto Rico. In this respect, it is provided that the relief from the 51% disallowance is provided when a deduction is supported by a transfer pricing study that has been prepared and is available at the time of filing…