South Florida's multinational population means many U.S. nationals in the region have assets in foreign countries, but many don't realize their overseas income is subject to U.S. income taxes, financial advisers say.

New residents are often surprised how quickly their tax obligations begin, and Venezuelans have the added disadvantage of exchange rate complications.

“As soon as you have been here 183 days in your first calendar year, you are subject to U.S. tax filings on your global taxable income regardless of where it arises,” said Michael A. Silva, an international tax partner at DLA Piper in Miami. “You can be subject to the U.S. global tax regime … even persons that stay here without lawful immigration status.”