Although ownership of a joint bank account passes to the surviving owner after one owner's death without having to go through probate, in most jurisdictions the contents of the joint account will still be subject to estate tax. For example, under Pennsylvania estate tax law, joint bank accounts owned by people other than spouses are subject to the estate tax, with the total balance of the account divided by the number of joint owners to determine the taxable amount, according to the Philadelphia Register of Wills. Noting the existence of a joint bank account in your will allows your executor to identify it and include it in your estate inventory more efficiently. This will save time and money, leaving more resources in your estate for distribution to your heirs.
Tenants in Common
Not all joint bank accounts are set up for ownership as joint tenants with rights of survivorship. Your share of a joint bank account owned as tenants in common rather than joint tenants will not pass automatically to the other owner of the account. You must designate through your will the person to whom you would like your portion of a tenants-in-common bank account to be transferred at your death.
A common disaster clause is a provision frequently included in spouses' mutual wills to set out what should happen to their assets in the event they die within a very short period of time from one another in something like an airplane crash or car accident. A bank account jointly held by you and your spouse should be included in your will along with a mutual disaster provision, so that in the event you both die within a very short period of time from one another, your executor and the probate court will have direction as to the disposition of the account contents.
Joint bank account owners, whether or not they are spouses, may well die within a few weeks, months, or years of one another, before the joint account has been retitled after the first owner's death. For example, an adult child may die in a car accident weeks before their parent, with whom they own a joint bank account, dies of natural causes. The parent may not have had the bank re-issue the formerly joint account as a single account in the intervening stressful weeks. Including mention of a joint bank account in your will assures that, if circumstances are such that the account has passed into your ownership at the time of your death, your executor and the probate court will be aware of your intentions for the disposition of the account.