Updated July 29, 2026. Quick answer: Puerto Rico’s Civil Code makes the sociedad legal de gananciales the default regime: couples who do not select another are subject to it, and it begins “at the very moment of the celebration of the marriage.” But IRS Publication 555 lists only the nine states and does not address Puerto Rico — so do not assume the federal rules transfer.
Community property in substance
The Civil Code treats both spouses as owners of the common property “in equality of rights and obligations”, and classifies as ganancial property acquired for value at the expense of the common fund and property obtained by the work or industry of either spouse. Functionally that is a community property system.
The gap is in the federal treatment, not the state law. Publication 555 is written for taxpayers domiciled in the nine states and does not extend its guidance to Puerto Rico. The Internal Revenue Manual does describe Guam and Puerto Rico as community property jurisdictions — but a manual description is not the same as published guidance you can rely on for a basis position.
And Puerto Rico’s tax relationship with the United States is its own subject. Residents are subject to a separate territorial income tax system and different federal filing rules. **Anyone weighing a basis question here needs advice specific to Puerto Rico rather than an analogy to California** — the civil-law ganancial regime is not simply the Spanish-language version of a community property statute.
What is safe to say
That the default regime is community in character, that it attaches at marriage without any election, and that the federal consequences are not settled by the same publication that settles them for the nine states. Anything more definite than that is going beyond what the published guidance supports.
Sources
Each state’s own codified statute as quoted on this page. The nine-state list and the federal treatment are per IRS Publication 555 and Internal Revenue Manual 25.18.1.2.3. IRC §1014(b)(6) for the basis consequence. All read July 2026.
This states what the cited authority says. It is not tax advice, and retirement-plan design turns on facts about your business and your other entities that no page can see. Every dollar limit referenced here is indexed and changes annually.