Usual disclaimer: I’m not a lawyer, everything here is for information purposes only. Consult a legal professional for legal advice.
Financial law is one of the most complex areas of legal systems. In addition to varying widely from one jurisdiction to another, financial law is also a wide-ranging area that affects just about every part of society. Which is another way of saying “I can only touch on the highlights. Here there be monsters.”
Taxes can be applied to all kinds of things. So can tax breaks. Depending on how the tax codes are written in your area, married folk may get tax breaks unavailable to single people, or single people may get tax breaks unavailable to married people, or both depending on the situation. No matter how the tax breaks fall, “married people” in much of the world applies only to couples, and in most of the rest of the world, only to couples or one man, several women. Both definitions exclude poly folk. The impact marriage has on finances extends to…
In many parts of the world, a spouse is assumed to inherit unless a will establishes other wise. A spouse may also have an advantage in challenging a will.
I can’t speak for the rest of the world, but in the US there are times and places where one person can own something or two people can own something but three people can’t. A car for instance can be registered as belonging to two people, but not to three or four people. This makes it difficult, if not impossible, for a polycule to jointly own something. And no matter how in love you are or how committed you are, for many people it’s hard to completely erase the awareness that your partners OWN the home, but you just live there.
Some jurisdictions have a fun twist on property law where it is assumed that what is owned by one person is automatically jointly owed by their legal spouse. This means that is A is married to B, but A and C jointly own a car, if B leaves B can claim the car as being just as much their property and demand either the car or compensation in the divorce settlement. While I don’t know of this happening, I can easily see joint property laws also have an impact on inheritance law.
Some polycules have gotten around the various headaches financial laws cause by forming corporations. A corporation can own property, manage money, etc. A corporation cannot be married and is thus not subject to joint property laws (though individual owners of a corporation may be).
Corporate law is a whole ‘nother headache partly within and partly separate from financial law. But it can be a very useful tool in getting around some of the problems financial laws cause poly folk. Just be prepared to talk with lawyers and make sure all your “i”s are dotted and “t”s are crossed.
Again, this is just a brief skim of some of the ways financial laws impact polyamory. Do what you can to learn about the way financial laws work in your part of the world, and if in doubt talk with a lawyer!