Ray purchases U.S. savings bonds that he lists as "Ray and Donna" as co-owners. Donna is Ray's daughter. Donna predeceases Ray. No gift or estate tax consequences result from this situation.
In 2008, Katelyn inherited considerable property when her father died. When Katelyn dies in 2020, her estate may be able to claim a credit as to some of the estate taxes paid by her father's estate.