The answer to your question is yes. You may not, however, have a tax home outside Puerto Rico or have a closer connection to the U.S. than Puerto Rico. Additionally, you'll need to receive a tax exemption decree from the Secretary of Economic Development and Commerce. Big note: the event triggering recognition of the gain has to occur while the taxpayer has the exemption status. So if an event triggering gain recognition occurred while the taxpayer was just a U.S. resident, it will be subject to U.S. income tax.