The spouse contribution tax offset: a modest $540, and the equalisation strategy it belongs to

For couples where one partner has worked part-time, taken career breaks, or earned significantly less over their working life, the result is often a lopsided pair of superannuation balances at retirement. The super system includes several tools specifically designed to address this — the best known being the spouse contribution tax offset, a clean 18% tax credit available when a working spouse contributes to a lower-income partner's super. On its own, the offset is modest: $540 per year at maximum. Understood as part of a broader equalisation strategy, it is one piece of a toolkit that can meaningfully shift the combined retirement position of a couple over time.

How does the spouse contribution tax offset work?

The mechanic is straightforward. The contributing spouse makes a non-concessional (after-tax) contribution to the receiving spouse's superannuation fund and claims an 18% tax offset in their own tax return. The offset applies to the first $3,000 of contributions, producing a maximum credit of $540 per year. The offset is non-refundable — it reduces tax payable rather than creating a cash refund — so the contributing spouse needs sufficient tax liability to make use of it (FirstTech Super Contribution Checklists 2025-26, Colonial First State).

Eligibility for the full $540 requires the receiving spouse's total income — calculated as assessable income plus reportable fringe benefits plus reportable employer super contributions — to be below $37,000. The offset phases down linearly above $37,000 and disappears entirely once the receiving spouse's income reaches $40,000. Below the threshold, the calculation is simply 18% of the contribution amount (up to $3,000). The receiving spouse must be under age 75 and have a total super balance below $2 million at 30 June 2025 to be eligible to receive contributions at all. The contribution must be made as a spouse contribution — not a personal contribution — and reported to the fund as such.

For couples where one spouse is on parental leave, working part-time, or in a lower-paid role, the offset is straightforward to claim each year and accumulates meaningfully over time. A couple claiming the full $540 over ten eligible years captures $5,400 in tax credits in addition to the compounding growth on the contributions themselves.

What other tools can couples use to equalise superannuation balances?

The spouse contribution tax offset is most valuable when one partner is on genuinely low income, but the broader strategy of equalising super balances applies in a wider range of circumstances.

Beyond the $3,000 that attracts the offset, further non-concessional contributions up to the receiving spouse's NCC cap can be made — though without the tax benefit. For 2025-26, the NCC cap is $120,000 per year ($360,000 under the three-year bring-forward for a receiving spouse with a total super balance below $1.76 million at 30 June 2025). These larger contributions, while not generating an offset, shift capital into the lower-balance spouse's account and produce the equalisation benefits described below.

Concessional contribution splitting allows a working spouse to transfer up to 85% of their concessional contributions from the previous financial year to the receiving spouse's superannuation fund. The 85% figure reflects the post-tax amount remaining after the 15% contributions tax. On the 2025-26 concessional cap of $30,000, the maximum annual split is $25,500 (FirstTech Strategy Matrix 2025-26, s.1.9). Splitting is applied in the financial year following the contribution year. The receiving spouse must be under their preservation age, or under 65 and not retired, at the time of the split. Where contributions were claimed as personal deductible contributions, a notice of intent to claim a deduction must be lodged and acknowledged by the fund before the split application is made. This mechanism allows couples to manage which partner's cap headroom is consumed each year and to deliberately build the lower-balance account over time.

Where the lower-balance spouse has a total super balance below $500,000 at 30 June 2025, carry-forward concessional contributions are also available — unused cap space from the prior five years can be contributed in a single year, subject to income. Combined with splitting, this allows catching up a significantly lagging balance relatively quickly.

Reversionary pension structures — while not a contribution strategy — represent a fourth equalisation mechanism. Nominating the lower-balance spouse as reversionary beneficiary ensures the higher-balance spouse's retirement phase pension transfers to them on death, rather than passing through the estate and potentially being received as a taxable lump sum.

Why does an unequal superannuation balance matter at retirement?

Unequal super balances produce several compounding disadvantages at retirement. Each spouse has their own Transfer Balance Cap (TBC) — currently $2 million for 2025-26 — which limits how much super can be moved into tax-exempt retirement phase pension. A couple with $2 million in one spouse's name and $400,000 in the other's has significant cap waste: the higher-balance spouse can only move $2 million into pension, while the lower-balance spouse's $400,000 cap sits largely unused. A more even split of $1.2 million each doubles the combined amount in tax-exempt pension earnings.

Similarly, the NCC bring-forward provisions are TSB-dependent. Once one spouse's TSB exceeds $2 million, they can no longer make NCCs at all. Equalisation preserves the combined household's capacity to contribute further. Where one spouse has already crossed the TSB threshold, concentrating future contributions in the other spouse's account can extend the window by years.

There is also an Age Pension dimension for couples with an age gap. Superannuation held in accumulation phase by a younger spouse is not assessable under the Age Pension means tests until that spouse themselves reaches Age Pension age (currently 67). This means a couple with a meaningful age difference can improve their combined Age Pension entitlement during the window between the older partner turning 67 and the younger partner doing the same, by shifting super assets toward the younger partner's account — particularly through concessional splitting.

What does a spousal superannuation equalisation strategy look like in practice?

Consider a couple where the contributing spouse earns $80,000 and the receiving spouse earns $25,000 from part-time work. A $3,000 non-concessional contribution to the receiving spouse's super generates a $540 tax offset for the contributing spouse — an 18% upfront return on a contribution that still sits in superannuation growing tax-effectively. The effective cost is $2,460 to add $3,000 to the couple's combined super base.

In a more complex pre-retirement scenario, consider a couple aged 60 and 58 with balances of $1.5 million and $400,000 respectively. A multi-year equalisation strategy — combining spousal NCCs (with the offset where the receiving spouse's income permits), annual concessional splitting of up to $25,500, and carry-forward contributions using the lower-balance spouse's unused cap — could close much of the gap over five years. The result is improved combined TBC headroom, preserved NCC capacity for both partners, and a more straightforward estate flow.

What are the limitations of spouse contribution strategies?

The offset itself is modest. For couples where neither spouse is on low income, it will not apply — but the concessional splitting and larger NCC strategies remain relevant regardless. For high-net-worth couples, the TBC and bring-forward considerations are typically more impactful than the $540 offset in dollar terms, though the offset is still worth claiming in eligible years.

The key practical requirement is ensuring the contribution is correctly categorised as a spouse contribution at the time it is made. Funds do not retrospectively reclassify contributions, and a personal contribution cannot be converted to a spouse contribution after the fact. For couples where the offset would apply, this is a simple administrative step that is worth confirming with the fund at the time of contribution.

For couples with meaningful asymmetry in their super balances, a coordinated multi-year approach across the available tools — offset, NCCs, splitting, and carry-forward — produces materially better outcomes than addressing any single tool in isolation.