The Simultaneous Death Act is a state or local law which provides that if two persons (usually a husband and wife) both die under conditions in which it is impossible to determine which one died first, the property of each person shall be disposed of as if he had survived, except as provided otherwise.

Such statutes generally provide that when property is so disposed of that the right of a beneficiary to succeed to any interest therein is conditional upon his surviving another person and both persons die, and there is no sufficient evidence that the two have died other than simultaneously, the beneficiary shall be deemed not to have survived.

In the case of life insurance, for example, it’s presumed the insured outlives the beneficiary, and the money goes to the secondary or contingent beneficiary. Deaths may be treated as simultaneous under the law even when one spouse dies within five days after the other one if both died due to a common accident.

The Mississippi Laws regarding Simultaneous death, provides in part as follows:

Where the title to property or the devolution thereof depends upon priority of death and there is no sufficient evidence that the persons have died otherwise than simultaneously, the property of each person shall be disposed of as if he had survived, except as provided otherwise in this chapter.

Where there is no sufficient evidence that two (2) joint tenants have died otherwise than simultaneously the property so held shall be distributed one half (1/2) as if one had survived and one half (1/2) as if the other had survived. If there are more than two (2) joint tenants and all of them have so died the property thus distributed shall be in the proportion that one bears to the whole number of joint tenants.

Where the insured and the beneficiary in a policy of life or accident insurance have died and there is insufficient evidence that they have died otherwise than simultaneously, the proceeds of the policy shall be distributed as if the insured had survived the beneficiary.

This chapter shall not apply in the case of wills, living trusts, deeds, contracts of insurance or other contracts wherein provision has been made for distribution of property different from the provisions of this chapter.  MS Code 91-3..

So if you do not make a Will that provides otherwise, the laws above apply.  This is also a good reason to have a Will.