Buying with a Friend or Sibling in Australia: Joint Tenants vs Tenants in Common

Introduction

Two in five Australian first-home buyers now purchase with a sibling, a friend or a relative other than a spouse, according to the Australian Bureau of Statistics’ 2023 lending indicators. The uptick tracks 400-basis-point cash rate increases delivered by the Reserve Bank of Australia between May 2022 and November 2023, pushing the national median dwelling price to income ratio past 8.0 times. Co-ownership structures – joint tenancy and tenancy in common – define how title is held, how debts are apportioned and who inherits the property. The distinction carries capital gains tax consequences administered by the Australian Taxation Office, survivorship rules under state Torrens legislation and joint-and-several liability under Australian Securities and Investments Commission-regulated credit contracts. This article sets out the legal anatomy, the lending frame and the fiscal arithmetic, without recommending any one arrangement for an individual borrower.

Joint Tenancy: The Four Unities and the Right of Survivorship

Joint tenants hold property together as a single legal entity. The four unities – possession, interest, time and title – must be present. Unity of possession gives each co-owner an equal right to occupy the whole property; unity of interest compels equal ownership shares; unity of time means all parties acquire their interest simultaneously; unity of title requires that all interests derive from the same instrument of transfer.

The right of survivorship is the defining feature. When one joint tenant dies, their interest extinguishes automatically and the surviving joint tenant or tenants assume full ownership by operation of law. The deceased’s share does not form part of their estate and cannot be diverted by a will. This mechanism avoids probate delays but can produce unintended estate-planning outcomes, particularly where parents and children appear on title as joint tenants. The Land Titles Office in each jurisdiction – for example, New South Wales Land Registry Services – records the transmission on death without a transfer instrument, relying solely on the lodged death certificate (NSW LRS Co-ownership Guide).

Joint tenancy is standard for married and de facto couples because the automatic vesting aligns with typical estate intentions. For siblings or friends the streamlines comes at a price: the survivor takes everything, regardless of other family claims. Lenders treat joint tenants as co-borrowers with joint-and-several liability, meaning each co-owner is liable for the full debt. A default by one party exposes the other to the entire loan balance. The Australian Prudential Regulation Authority’s APS 220 credit risk standard does not relax capital treatment for joint-tenancy mortgages; the whole exposure is attributed to each obligor for risk-weighting purposes.

Tenancy in Common: Proportional Ownership Without Survivorship

Tenants in common hold separate, fractional interests in a single property. The four unities are replaced by a single unity – possession. Each co-owner may hold a distinct share (e.g. 60/40, 99/1, 50/50), acquired at different times and through different instruments. The share exists as an alienable asset: a tenant in common can mortgage, sell or bequeath their interest without requiring consent from the other owners, subject to any contractual restrictions recorded on title.

There is no right of survivorship. On death, the deceased’s share passes according to their will or under the laws of intestacy. This makes tenancy in common the default arrangement for unrelated co-buyers – siblings pooling a deposit, friends entering a property venture, or parents contributing equity while children service the loan. The title register maintained by each state’s land titles office records the precise fractional entitlement; for example, a Victorian transfer of land form will list “as tenants in common in unequal shares”.

Stamp duty and transfer duty consequences follow the proportionate share. Where a parent contributes 20% of the purchase price and is shown as a 20% tenant in common, the Office of State Revenue in the relevant jurisdiction assesses duty on that 20% interest at the time of original acquisition. Further duty may crystallise on a subsequent transfer of the remaining 80% if a partition or sale reallocates shares. Lenders appraise the borrowing entity as a set of individual debtors: the Australian Securities and Investments Commission’s responsible lending guidelines (RG 209) require the credit provider to assess each co-borrower’s financial situation, including the capacity to service the entire loan if the other co-borrower ceases contributions (ASIC MoneySmart Co-Borrowing).

Mortgage and Lending Implications for Co-Borrowers

Lenders structure co-ownership loans as joint debts. The standard Australian home loan contract, regulated by the National Consumer Credit Protection Act 2009, imposes joint-and-several liability irrespective of the title form. A joint tenant and a tenant in common face identical repayment obligations; the distinction operates at property law level, not at the credit contract level.

Serviceability assessment aggregates the gross incomes of all applicants but applies a scaled-down treatment to variable or freelance earnings. The Australian Prudential Regulation Authority’s prudential practice guide APG 223 Residential Mortgage Lending requires authorised deposit-taking institutions to apply a minimum 3-percentage-point interest rate buffer over the loan’s actual rate and to model the ability of each borrower to meet repayments if one income stream is lost. For co-owners who are not spouses, the buffer test can constrain borrowing power if the lender selects the more conservative single-income scenario. Some smaller authorised deposit-taking institutions may offer “property share” loans where liability is several rather than joint, but these products carry interest rate premiums of 30 to 70 basis points above standard variable rates and require separate legal representation for each party.

Loan-to-valuation ratios for co-ownership purchases are determined by the aggregate deposit. An 80% LVR eliminates lenders mortgage insurance; an LVR above 80% requires LMI, with the premium escalating at a non-linear rate. From 1 January 2025, APRA’s revised macroprudential framework expects ADIs to hold additional capital against high-DTI lending. A debt-to-income ratio exceeding 6.0 times will attract a risk-weight uplift, directly affecting the pricing of co-borrower loans where the combined income is modest relative to the property value. Prospective co-buyers should obtain credit reports from all three bureaus (Equifax, illion, Experian) before application: a default by one co-owner post-settlement can trigger a loan recall clause under the General Terms and Conditions for Residential Loans published by the Australian Banking Association.

Tax Consequences: CGT, Transfer Duties and the ATO

The Australian Taxation Office treats co-ownership interests as separate CGT assets (ATO Property and Capital Gains Tax). A tenant in common who sells their share triggers a CGT event on that proportion. The main residence exemption can apply to a tenant in common if the property was their principal place of residence; a joint tenant who moves out and later sells may lose the full exemption unless the six-year absence rule is utilised. Where a parent holds a 20% interest as tenant in common in a child’s home, that 20% share will not qualify as the parent’s main residence and CGT will be assessed on disposal, with a 50% general discount available if the interest has been held for at least 12 months. The ATO’s data-matching program cross-references title transfers lodged with state land registries against individual tax returns.

Stamp duty on the initial purchase is straightforward – duty is levied on the full purchase price and paid by or on behalf of all co-owners. “Change in beneficial ownership” provisions can trigger duty on later rearrangements. If two tenants in common alter their respective shares from 50/50 to 70/30, the 20% shift constitutes a dutiable transaction in New South Wales, Victoria and Queensland unless a specific exemption (such as a marriage or relationship breakdown) applies. Joint tenants who sever the joint tenancy and become tenants in common generally do not incur duty, provided no consideration passes, but Revenue NSW and the State Revenue Office Victoria require lodgment of a dutiable transaction statement to confirm the exemption.

Land tax is assessed on the aggregated land value for joint tenants, while individual tenants in common are assessed separately on their fractional interest. This structure can lower land tax liability in states with progressive scales (e.g. Victoria, where the top marginal rate of 2.25% applies to taxable land values above $5 million). For sibling co-owners using the property as an investment, a tenancy in common with asymmetric shares can keep each co-owner beneath the land tax threshold – $350,000 in New South Wales for 2025 – or delay the higher marginal rate bracket.

Making the Choice: Legal and Financial Factors

Co-buyers must confront two decisions: the title form and the financial architecture. The right of survivorship is the pivot. Siblings who wish their children to inherit a share cannot use joint tenancy; the survivor takes all and the deceased’s children receive nothing from the property interest. Friends who contribute unequal deposits cannot use joint tenancy because unity of interest demands equal shares. Tenancy in common accommodates unequal capital contributions and permits a co-owner to exit by selling their share, though the market for a minority interest in a residential property is thin and often discounts 15% to 25% relative to the pro rata market value.

A written co-ownership agreement – while not a statutory requirement – can document the initial contributions, ongoing expense allocation (mortgage, rates, insurance, maintenance), dispute resolution mechanisms and exit clauses. The agreement does not override the Certificate of Title, but it can underpin equitable claims and reduce litigation costs. The Supreme Court of Victoria has held in several 2022-2024 partition-and-sale proceedings that undocumented oral arrangements between friends fail when relationships deteriorate; costs orders routinely exceed $80,000.

Mortgage strategy requires an exit plan. Fixed-rate terms of one to five years provide payment certainty but can entrap co-borrowers if one wants to sell during a fixed-rate lock. Break costs for an average $600,000 fixed-rate loan can exceed $12,000 in the first year. A variable-rate loan with offset facilities allows each co-owner to park savings against the loan balance and reduce interest while preserving individual control of funds, provided offset accounts are designated as several rather than joint.

Severing a Joint Tenancy and Changing Title

A joint tenancy can be severed unilaterally or by mutual agreement. Severance converts the title into a tenancy in common in equal shares. The most common method is the registered transfer of one joint tenant’s interest to themselves, creating the duality of parties required for a tenancy in common. A transfer under the Real Property Act 1900 (NSW) or the Transfer of Land Act 1958 (Vic) must be registered with the land titles office. Registration fees range from $155 to $350 depending on the state, and the title search cost is approximately $25. No duty is payable provided the transfer is not subject to monetary consideration.

Severance does not alter the mortgage covenant. The lender’s consent may be required under the mortgage memorandum, and banks routinely impose a fee of $300 to $600 to record the change. If the loan product includes a guarantor, severance may trigger a reassessment. The discharged joint tenant’s interest becomes a separate CGT asset from the date of severance, meaning two CGT events will occur on eventual sale rather than one; for investment properties this can defer crystallisation of part of the gain to a later income year.

Conclusion

The choice between joint tenancy and tenancy in common shifts the entire axis of property risk. A right of survivorship can make estate planning simple or catastrophic; a proportional share can be a tax-efficient lever or a liquidity trap. Co-buyers who finance through an ADI-regulated loan are bound by joint-and-several liability regardless of title form, and APRA’s serviceability floor shapes the borrowing ceiling more than any nominal interest rate. Stamp duty, land tax and CGT outcomes then cascade from the ownership structure selected. The data is clear – the incidence of co-ownership with non-spouses is rising – but the legal, credit and tax architecture has not been redesigned to buffer the friction that arises when friends and siblings hold property together.

Information only, not personal financial advice. Consult a licensed mortgage broker.