According to JTWROS regulations, which rule applies when determining the inclusion of property in a decedent's gross estate?

The correct answer pertains to the inclusion of property in a decedent's gross estate based on the decedent's contribution to the property's purchase price in a Joint Tenancy with Right of Survivorship (JTWROS) arrangement. Under JTWROS regulations, when a joint tenant passes away, the property does not automatically become fully the property of the survivor; rather, the decedent's interest in the property is determined by their contribution to its purchase.

In situations where there are multiple joint tenants, the portion of the property included in the decedent's gross estate reflects only the proportionate share based on what the decedent contributed financially to acquire the property. This rule ensures that the estate is assessed fairly based on actual financial contributions rather than arbitrary ownership designations.

Hence, the focus on the decedent's contribution to the purchase price captures the true economic interest of the deceased in the asset, aligning with principles of fair estate valuation and tax implications.