Bonds issued by the government of Puerto Rico and its subdivisions are exempt from federal, state, and local taxes (so called "triple tax exemption"). However, unlike other triple tax exempt bonds, Puerto Rican bonds uphold such exemption regardless of where the bond holder resides.[a] This has made Puerto Rican bonds extremely attractive to municipal investors as they may inure from holding a bond issued by a state or municipality different from the one where they reside. This advantage strives from the restriction typically imposed by municipal bonds enjoying triple tax exemption where such exemptions solely apply for bond holders that reside in the state or municipal subdivision that issues them.
This factor, along with many others, led Puerto Rico to issue bonds carelessly and without repayment method up to today's outstanding debt of $71 billion USD—an amount approximately equal to about 68% of Puerto Rico's gross domestic product (GDP). These actions, along with a series of negative cash flows and a depression, ultimately led to Puerto Rico's government-debt crisis.
^Pub.L. 64–145 §3 "[...] all bonds issued by the government of Porto Rico, or by its authority, shall be exempt from taxation by the government of the United States, or by the government of Porto Rico or of any political or municipal subdivision thereof, or by any state, or by any county, municipality, or other municipal subdivision of any state or territory of the United States, or by the District of Columbia."