SIS dependant vs tax dependant: two definitions, one super death benefit, frequent confusion

For Australian retirees and the family members who will eventually receive their super, a frequently misunderstood feature of the system is that two different dependant definitions govern superannuation death benefits. The first sits under the Superannuation Industry (Supervision) Act 1993 (SIS Act) — sections 10 and 10A — and decides who the trustee can pay the death benefit to. The second sits under the Income Tax Assessment Act 1997, section 302-195 — and decides whether the death benefit is taxed or passes tax-free. The two definitions overlap substantially but are not identical, and the most common divergence catches out the most common family situation: parents leaving super to adult, financially independent children.

The SIS Act dependant definition governs who the super fund trustee can pay the benefit to. It includes the spouse (legal, de facto, and certain registered relationships, same- or opposite-sex), child (biological, adopted, stepchild, and child within the meaning of the Family Law Act 1975), person in an interdependency relationship (close personal relationship, living together, with one or each providing the other with financial and domestic support and personal care), and financial dependant (a person financially dependent on the member at the time of death). For the SIS Act child definition, age and financial independence are not relevant — a 50-year-old financially independent child is still a SIS Act child of the member. This is the universe of people who can receive a death benefit. A binding death benefit nomination (BDBN) can only nominate beneficiaries who fall within this universe, plus the legal personal representative (LPR / executor of the estate).

The tax dependant definition under section 302-195 is similar but with a critical narrowing. It includes the spouse at the time of death, child of the deceased aged under 18 (i.e., minor children only), person in an interdependency relationship at the time of death (substantially the same definition as SIS), and financial dependant at the time of death. The crucial difference: adult children aged 18 or over are not tax dependants unless they are financially dependent on the member or in an interdependency relationship with the member. A financially independent 35-year-old child of the deceased is a SIS Act dependant (a "child") but not a tax dependant.

The tax consequences of the divergence are direct. When a death benefit is paid to a tax dependant, the lump sum passes tax-free in its entirety — both the tax-free component and the taxable component. When a death benefit is paid to a non-tax-dependant, the tax-free component still passes tax-free, but the taxable component (taxed element — the typical case for APRA-regulated super) is taxed at 15% plus 2% Medicare levy = 17% effective. The taxable component (untaxed element — typically unfunded public sector schemes and certain insurance proceeds) is taxed at 30% plus Medicare levy = 32% effective. For most retirees with APRA-regulated super where the bulk of the balance is taxable taxed element, the 17% rate applies to the taxable component of a benefit paid to an adult child.

The arithmetic matters. A $500,000 death benefit composed entirely of taxable taxed element to an adult child produces approximately $85,000 of tax. A $1m benefit to an adult child produces approximately $170,000 of tax. These amounts reduce what the family receives — money that goes to the ATO rather than to the next generation.

A few practical scenarios illustrate the dynamic. Member with spouse and adult children — death benefit naturally pays to the spouse first. The spouse is a tax dependant; the benefit passes tax-free. The spouse later dies; super accumulated in the spouse's account passes to the adult children, with 17% tax on the taxable component (unless mitigated). Single member with adult children — the trustee can pay the children (SIS dependants) but 17% tax applies. The benefit can alternatively pass to the LPR (estate) and be distributed under the will, with similar tax treatment but different administrative consequences. Member with adult child still genuinely financially dependent — for example, an adult child with disability supported by the member — the child is both SIS and tax dependant; the benefit passes tax-free. Member in long-term close relationship with sibling, friend, or carer — where the relationship meets the interdependency test (close personal, living together, financial and domestic support, personal care), the person is both SIS and tax dependant; documentation supports the position.

A note on Binding Death Benefit Nominations. The BDBN can only nominate SIS dependants or the LPR — those are the permissible recipients under the SIS Act. A BDBN nominating an adult niece directly, or a charity, is invalid. The BDBN can nominate adult children — they are SIS dependants — but the tax outcome when the benefit is paid is governed by the tax dependant test, not the BDBN. The BDBN governs who gets paid; the tax dependant test governs how it's taxed. Many retirees assume nominating their children in a BDBN secures tax-free treatment; it does not.

Several strategies address the divergence where the eventual recipient is an adult child. The most powerful is the recontribution strategy — converting taxable component to tax-free component by withdrawing super (for a member over 60 in retirement, withdrawals are tax-free) and re-contributing as a non-concessional contribution. The recontributed amount becomes tax-free component, which passes to non-tax-dependants without tax. Multi-year application can shift a substantial portion of the balance from taxable to tax-free. The NCC cap ($120,000 in 2025-26) and the bring-forward rule (up to $360,000 in one contribution, subject to TSB at the previous 30 June) limit the rate of conversion but support meaningful progress over years. Pay through the spouse first — the natural pathway where there's a surviving spouse — combines tax-free first transfer with subsequent recontribution by the spouse over their remaining life. LPR routing through the estate has similar tax treatment to direct payment but different administration; testamentary trust structures can sometimes provide post-tax distribution advantages. Insurance held outside super is not subject to the death benefit tax framework; structuring some life cover outside super provides tax-free death benefit with different administrative features.

A few common pitfalls. Assuming all SIS dependants get tax-free treatment — adult financially independent children are typically not tax dependants. Confusing the two definitions — they overlap but are not identical. Inadequate BDBN — nominating a non-SIS-dependant invalidates the nomination. Not implementing recontribution where the eventual recipient is an adult child. Not tracking interdependency for non-traditional families where the relationship may meet the criteria.

For Australian retirees with adult children, the SIS dependant vs tax dependant divergence is one of the most important features of super death benefit planning. The tax can be substantial; the strategies are real; the documentation supports cleaner outcomes. Worth understanding deliberately rather than discovering at the difficult moment.