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-- A Puerto Rican tax return reporting income from worldwide sources. If you report U.S. source income on your Puerto Rican tax return, you can claim a credit against your Puerto Rican tax, up to the amount allowable, for income taxes paid to the United States.
-- A U.S. tax return reporting income from worldwide sources, but excluding Puerto Rican source income.
-- If you are excluding Puerto Rican income on your U.S. tax return, you will not be allowed any deductions or credits that are directly or indirectly allocable to exempt income.
-- If all of your income is from Puerto Rican sources, you are not required to file a U.S. tax return.
If you are a U.S. citizen, you may also qualify under these rules if you have been a bona fide resident of Puerto Rico for at least 2 years before moving from Puerto Rico. In this case, you can exclude your income derived from sources within Puerto Rico (but not wages and salaries received as an employee of the U.S. Government or its agencies) that you earned before the date you changed your residence.
Please see for reference IRS publication 570 - www.irs.gov/pub/irs-pdf/p570.pdf Let me know if you need any help or clarification.