On December 10, 2018, the Puerto Rican Government enacted important amendments to the Puerto Rico Internal Revenue Code of 2011 (PRIRC), amended as Act No. 257-2018. For detailed coverage of the provisions introduced and amended by Act No. 257-2018, see our Tax Insight 'Puerto Rico adopts significant amendments to its income tax code' published on January 17, 2019. In particular, the new law requires taxpayers to submit a transfer pricing study with their Puerto Rico income tax returns to avoid the 51 % disallowance on expenses or fees accrued or paid to non-PR resident related parties not engaged in trade or business in Puerto Rico (the 51 % cross-border intercompany expense disallowance).