Act 60 seems like a limited tax incentive scheme. I'm referring to the general clause that income of Puerto Rican residents sourced in PR is not subject to personal income tax. From your linked source:
> The U.S. tax code (Section 933) allows a bona fide resident of Puerto Rico to exclude Puerto Rico-source income from his or her U.S. gross income for U.S. tax purposes.
> The U.S. tax code (Section 933) allows a bona fide resident of Puerto Rico to exclude Puerto Rico-source income from his or her U.S. gross income for U.S. tax purposes.
Or there's more on the Wikipedia page: https://en.wikipedia.org/wiki/Taxation_in_Puerto_Rico#Federa...