The simultaneous death rule in Missouri

We spend a lot of time in this blog talking about dealing with the worst-case scenario–your death or prolonged disability. What might be even worse, though, is a situation when your heirs die at the same time you do.

And sadly, this does happen sometimes. CNBC points out that recently there have been some high-profile relative deaths: Carrie Fisher and Debbie Reynolds, for instance. Of course, accidents, natural disasters, fires, and other disasters can also cause multiple deaths.

Why does that matter? Because determining who the heirs of an estate are depends on who survives the deceased person. We did a lot on this back in our discussion of per stirpes and per capita, so you might want to check that out (it has charts!). When an heir dies close to the time the deceased person died, we need a way to determine whether or not to count that person as an heir. That rule is called the “simultaneous death rule” or the “120-hour rule.”

What does the simultaneous death rule say?

In Missouri, the simultaneous death rule says that if an heir of a deceased person dies within 120 hours of the deceased person, that heir is considered to have died before the original deceased person. You probably already have this figured out, but that’s also why it’s known as the “120-hour rule.”

Of course, we don’t always know the exact time of someone’s death, and the rule deals with that problem too. Specifically, it says that if the time of death of the decedent or the heir cannot be established, and we can’t be sure that the heir survived by 120 hours, then the heir is determined to have died first.

What if I have a will?

If you have a will, your devisees (the people who take property from your estate through your will) are subject to the 120-hour rule too. However, it’s what we call a “default rule,” meaning that you can change it in your will if you want. In my experience, most of the people I work with don’t really care too much about the rule. That said, you can definitely change it if you choose.


The other issue¬†that CNBC article brings up is the need for backups. We’ve talked about this before, and I’ll just refer you to that post, but I recommend that you always have at least one backup for every person that manages your estate or takes property for your estate.

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