The general rule: survivorship is abolished
The Illinois Joint Tenancy Act (765 ILCS 1005/2) starts with a broad rule: except as to executors and trustees, and except where a will or other written instrument expresses an intention to create survivorship in personal property, the right of survivorship between joint owners of personal property is abolished. Any such joint ownership is deemed a tenancy in common instead — meaning, absent a written expression of intent, a deceased co-owner's share of that personal property goes through probate rather than automatically passing to the survivor.
Bank deposits get their own exception
Immediately after stating that general rule, the same statute carves out a specific list of exceptions it doesn't intend to disturb. The first of these covers deposits at a bank or trust company — preserving survivorship rights for jointly held bank accounts even without a separate written instrument specifically expressing that intent. This means an ordinary joint bank account in Illinois can carry survivorship by virtue of this built-in statutory exception, distinct from the general personal-property rule that would otherwise require a written expression of intent.
Securities get a parallel exception
The same section extends similar protection to jointly held securities. When stocks, bonds, or other evidences of indebtedness or interest are issued or registered in the names of two or more people as joint tenants with right of survivorship, that survivorship right is preserved by statute as well — not left to depend on a separate written instrument the way the general personal-property rule would otherwise require.
Institutions can rely on the registration without digging deeper
Illinois law gives financial institutions real practical protection here. A corporation, association, or other entity — and its transfer agents — may transfer jointly registered shares, bonds, or similar interests to the surviving owner upon the death of one of them, without inquiry into the existence, validity, or effect of any will or other written instrument, and without liability to anyone else who might claim an interest in the property. This lets a bank or transfer agent act on the registration itself rather than investigating the deeper legal question of who's truly entitled to the funds.
P.O.D. designations, life insurance, and retirement accounts
A payable-on-death (P.O.D.) beneficiary designation works differently from joint ownership between co-owners. The named P.O.D. beneficiary has no rights to the account during the owner's life, and receives whatever remains only once the owner dies. Life insurance and retirement accounts like a 401(k) or IRA follow the same basic rule — the named beneficiary receives the asset directly, outside probate, as long as they're alive when the owner dies, and it only becomes part of the probate estate if no beneficiary was ever named or every named beneficiary predeceased the owner with no contingent beneficiary in place.