An interdependency relationship — close personal relationship, cohabitation, financial support, and domestic/personal care, all four required — lets a non-spouse beneficiary like a caring adult child inherit a super death benefit tax-free, the same as a spouse. Without it, a non-dependent adult child pays 17% on the taxable component. A properly documented case, backed by a binding death benefit nomination or reversionary pension, secures this treatment.
Most retirees and their advisers think of super death benefits through a spousal lens. The surviving spouse takes the death benefit tax-free; non-dependent adult children pay tax on the taxable component. The third category of SIS death benefit dependant — the interdependent — gets far less attention than it deserves. For an adult child who has moved back into an elderly parent's home to provide care, for sibling pairs cohabiting in retirement, for long-term housemates supporting each other, the interdependency status is the difference between a tax-free death benefit and one taxed at up to 17% on the taxable component — 15% plus 2% Medicare Levy when paid direct to a non-dependent beneficiary (ATO, https://www.ato.gov.au/individuals-and-families/super-for-individuals-and-families/super/withdrawing-and-using-your-super/superannuation-death-benefits).
The legal definition sits in section 10A of the Superannuation Industry (Supervision) Act 1993, with the detailed requirements in Regulation 1.04AAAA of the SIS Regulations 1994. Two persons are in an interdependency relationship if they have a close personal relationship, live together, one or each provides the other with financial support, and one or each provides the other with domestic support and personal care — all four elements must be met (ATO, https://www.ato.gov.au/individuals-and-families/super-for-individuals-and-families/super/withdrawing-and-using-your-super/early-access-to-super/access-on-compassionate-grounds/access-on-compassionate-grounds-what-you-need-to-know/interdependent-relationship-checklist). There is an alternate path where the close personal relationship exists but the other elements cannot be met because of a physical, intellectual, or psychiatric disability. There is also an explicit exclusion: a person providing domestic support and personal care under an employment contract or on behalf of an organisation does not qualify. A paid carer is excluded; an unpaid family member living in the home meets the test.
The tax consequence is the headline. A lump-sum super death benefit paid to a SIS dependant — whether spouse, child under 18, financial dependant, or interdependent — is tax-free regardless of the taxable/tax-free component split. The same lump sum paid to a non-dependent adult child is split: the tax-free component is tax-free, but the taxable component (taxed element) is taxed at 15% plus 2% Medicare Levy = 17% effective. For a $500,000 taxable component flowing to a non-dependent adult child, that is $85,000 in tax. If the same adult child qualifies as an interdependent, the $500,000 is tax-free. The difference between the two classifications is the classification alone.
The classic case is now common enough to be unremarkable: an adult child moves back into an elderly parent's home to provide care. They share the household — bills, meals, transport, medical management. Centrelink Carer Allowance flows to the adult child. The arrangement has been in place for years before the parent's death. This is the textbook interdependency relationship. Provided the four elements are satisfied and the trustee accepts the evidence, the death benefit flows tax-free to that adult child.
The evidentiary requirement is real. Establishing interdependency is not a matter of declaration — it requires documentation. Joint bank accounts or shared household bills demonstrate financial support. Medical records and Carer Allowance receipts demonstrate personal care. Mailing address evidence — utility bills, vehicle registrations, electoral roll entries — confirms cohabitation. Statutory declarations from doctors, accountants, neighbours, or family members support the close personal relationship element. The super fund trustee makes the initial determination; disputed cases go to the Australian Financial Complaints Authority or the courts. A short-term arrangement of convenience will not satisfy the test. Long-term cohabitation with documented mutual support will.
The structural protection is the binding death benefit nomination. Without one, the trustee retains discretion — and in a contested estate, may not exercise that discretion in favour of the cohabiting adult child against other adult siblings who have not been involved in the day-to-day care. With a properly executed binding nomination naming the adult child as an interdependent, the trustee must pay them, subject to evidentiary verification at death. For retirees in account-based pension phase, the reversionary pension nomination is the mechanically cleanest route — the pension continues to the interdependent on the original member's death, with no commutation, no estate involvement, and no liquidity event. The reversionary nominee must still qualify as a SIS dependant at the date of death: if the adult child moves out before the parent's death, the interdependency lapses and the reversionary nomination fails. For retirees with substantial pensions, the interdependent's Transfer Balance Cap of $2.0 million (as at 1 July 2025) also applies — any balance in excess must be commuted within 12 months of death.
For retirees with an adult child in a caring arrangement, the interdependency structure is one of the highest-value pieces of estate planning available. The tax difference is substantial, the evidentiary work is achievable, and the structural tools — binding nominations and reversionary pensions — are well-established.
Sources
- Australian Taxation Office (ATO) — Superannuation death benefits
- Australian Taxation Office (ATO) — Interdependent relationship checklist
- Federal Register of Legislation — F2016C00515
Key takeaways
- An interdependency relationship, defined in s.10A of the SIS Act and Regulation 1.04AAAA, requires all four elements to be met: a close personal relationship, living together, one or each providing financial support, and one or each providing domestic support and personal care.
- A super death benefit paid to a SIS dependant — including someone in an interdependency relationship — is entirely tax-free regardless of the taxable/tax-free component split, while the same benefit paid to a non-dependent adult child has its taxable component taxed at 15% plus 2% Medicare Levy (17% effective).
- A paid carer under an employment contract or acting on behalf of an organisation is explicitly excluded from interdependency status — an unpaid family member providing the same care while living in the home can meet the test.
- Establishing interdependency requires real documentation: joint bank accounts or shared bills for financial support, medical records and Carer Allowance receipts for personal care, mailing address evidence for cohabitation, and statutory declarations supporting the close personal relationship — a short-term arrangement of convenience won't satisfy the test.
- A binding death benefit nomination removes the trustee's discretion and directs the benefit to the interdependent beneficiary, while a reversionary pension nomination avoids commutation and estate involvement entirely — though the interdependency must still exist at the date of death, and any pension balance above the interdependent's Transfer Balance Cap ($2.0 million as at 1 July 2025) must be commuted within 12 months.
Frequently asked questions
What is an interdependency relationship for super death benefit purposes?
It's a legal category defined in s.10A of the SIS Act, requiring all four of: a close personal relationship, living together, one or each person providing financial support, and one or each providing domestic support and personal care. There's an alternate path where the close personal relationship exists but the other elements can't be met due to a disability.
Can an adult child who moves in to care for a parent inherit their super tax-free?
Yes, if they can establish an interdependency relationship with their parent — a common scenario when an adult child moves back home to provide care, sharing bills, meals, and receiving Centrelink Carer Allowance over an extended period. If the four elements are satisfied and documented, the death benefit is tax-free, the same treatment as for a spouse.
How much tax does a non-dependent adult child pay on an inherited super death benefit?
The taxable component of a lump-sum death benefit paid to a non-dependent adult child is taxed at 15% plus 2% Medicare Levy, an effective 17%. On a $500,000 taxable component, that's $85,000 in tax — compared to zero tax if the same adult child qualifies as an interdependent instead.
What evidence do I need to prove an interdependency relationship?
Joint bank accounts or shared household bills to show financial support, medical records and Carer Allowance receipts to show personal care, mailing address evidence like utility bills or electoral roll entries to confirm cohabitation, and statutory declarations from doctors, accountants, neighbours, or family members to support the close personal relationship. The super fund trustee makes the initial determination, with disputes going to AFCA or the courts.