Mortgage serviceability arithmetic has become the dominant underwriting filter in Australia’s post-pandemic housing market. With the Reserve Bank’s cash rate target at 4.35% and most owner‑occupier variable rates near 6.50% p.a., the 3‑percentage‑point buffer APRA cemented on 6 October 2021 forces lenders to test new borrowers at a floor rate of at least 9.50%. For first‑home buyers using the federal First Home Guarantee – which allows a 5% deposit without lenders mortgage insurance – the relevant ceiling is no longer just the scheme’s published cap. It is the intersection of that cap, the income a household can service at the buffer rate, and the in‑house debt‑to‑income limit the chosen lender applies. Housing Australia activated fresh price caps on 1 July 2023, lifting the Sydney threshold to $900,000 and Melbourne to $800,000, just as the rate cycle was compressing borrowing capacity by roughly 20–25% compared with the ultra‑low‑rate environment that prevailed when the guarantee was first legislated. The participating lender panel – 33 institutions spanning the big four, mutuals, and non‑banks – became the filter through which the headline caps must pass. Understanding their internal credit overlays has become as critical as knowing the maximum purchase price for a postcode.
Price Cap Revisions and the Rate Cycle Collision
The 2023–24 price cap update was designed to keep the scheme relevant after two years of strong dwelling price growth. But the revised ceilings landed inside a credit environment that had already started shredding serviceability margins.
State‑by‑State Caps from 1 July 2023
Housing Australia’s 2023–24 schedule, effective 1 July 2023, sets the following maximum property values for the First Home Guarantee:
| State / Territory – Region | FHBG Cap |
|---|---|
| NSW – All areas | $900,000 |
| VIC – All areas | $800,000 |
| QLD – All areas | $700,000 |
| WA – Perth | $600,000 |
| WA – remainder of state | $450,000 |
| SA – Adelaide | $600,000 |
| SA – remainder of state | $450,000 |
| TAS – Hobart | $600,000 |
| TAS – remainder of state | $450,000 |
| ACT – whole territory | $750,000 |
| NT – Darwin | $600,000 |
| NT – remainder of state | $450,000 |
| Jervis Bay Territory | $900,000 |
| Norfolk Island | $600,000 |
These figures lifted the Sydney cap by $100,000 and added $200,000 in a number of regional centres compared with the previous year. The Budget Paper No. 2 of 9 May 2023 noted the expansion would increase the pool of eligible properties, especially in high‑cost cities where median unit prices had already breached the old caps. Yet the same budget was handed down when the average owner‑occupier discount variable rate was already above 5.50% p.a., and before three more RBA hikes pushed it above 6.00%.
Why the Cap Increase Arrives Half‑Empty
Raising a price ceiling is conceptually expansionary, but the effective take‑up is being compressed from the income side. APRA’s October 2021 policy requires a serviceability assessment at a rate that is the higher of the product rate plus 3 percentage points or the lender’s internal floor (typically 5.50–6.00%). For a 6.50% mortgage, the assessment rate becomes 9.50%. On a $900,000 loan – the Sydney maximum – monthly principal‑and‑interest repayments at 9.50% over 30 years reach $7,562. A household with one income‑earner on $120,000 and a partner on $80,000 might generate a net monthly income of roughly $12,000 after tax. After the lender’s benchmark living expenses (HEM) and any credit‑card limits, the surplus is often insufficient to pass serviceability for the full cap amount, even if the loan‑to‑value ratio is a comfortable 95% under the guarantee. Consequently, the cap becomes aspirational for many single buyers and dual‑income couples with average earnings, especially those carrying car loans or credit‑card debt.
The 33‑Lender Panel and the Credit Overlay Mosaic
Scheme eligibility is channelled through a panel of 33 lenders, each with its own interpretation of the guarantee’s risk parameters. While the government guarantee covers 15% of the property’s value, the lender retains full responsibility for credit assessment. The result is a patchwork of internal policies that can make or break an application.
Major Bank Policies – DTI Caps and Buffer Discipline
Commonwealth Bank, Westpac, NAB, and ANZ all participate and collectively dominate originations. Their credit guides for FHBG loans, current as of mid‑2024, generally carry the following overlays:
- Maximum LVR: 95% inclusive of the guarantee, eliminating the need for LMI. No secondary loan accountholder is allowed unless they are a spouse or de facto partner.
- Debt‑to‑Income (DTI): A hard cap at 7 times gross income is typical. Some assessors apply a 6.5‑times limit if other risk indicators are high. On exception, ANZ and Westpac may allow 8‑times DTI for professionals with strong income trajectory, but the exception rate is low during the current cycle.
- Serviceability buffer: The full 3.00% APRA benchmark is applied, with the floor rate set inside the lender’s scorecard. For a 95% LVR loan under the guarantee, a positive net income surplus of at least $1 per fortnight after buffers is mandatory.
Those parameters mean a couple with a gross household income of $180,000 can realistically borrow only about $1,260,000 under a 7‑times DTI, but serviceability at 9.50% trims that further to roughly $850,000–$920,000 when living expenses are accounted for. The Sydney cap of $900,000 therefore sits right at the razor’s edge for an average professional couple, and is out of reach if the buyer is single on $120,000. Melbourne’s $800,000 cap is more workable under the same math, while Brisbane’s $700,000 cap leaves headroom for many dual‑income borrowers.
Non‑Bank and Mutual Lenders – Flexibility at the Margin
Twenty‑eight non‑bank and mutual ADIs populate the panel, including Bendigo and Adelaide Bank, Bank Australia, Hume Bank, Regional Australia Bank, and Gateway Bank. Their product features can tilt the calculus in the buyer’s favour:
- Lower headline rates: Several mutuals price owner‑occupier variable loans 20–40 basis points below the major banks. A 6.10% rate drops the assessment rate to 9.10%, improving net surplus by roughly $190 per month on a $900,000 loan. That can be decisive.
- DTI tolerance: Some institutions, including Bendigo and Adelaide Bank, publicly indicate they will consider DTIs above 7 times where the applicant has strong residual income, stable employment in an essential service sector, or a clean credit history. Bank Australia’s credit guide allows up to 8 times for very‑strong‑profile borrowers.
- Lender’s mortgage insurance (LMI) experience: Although the guarantee removes LMI, the panel lender must still manage the settlement process. Non‑banks that process a high volume of government‑guaranteed loans often have faster document turnarounds, which matters when a vendor is pressing for an unconditional exchange.
Lender Processing and the Settlement Window
The FHBG requires pre‑approval and a reservation of a guarantee place before a contract is signed. Participation in the scheme is capped at 35,000 places per financial year. When a lender’s processing team is unfamiliar with the Housing Australia portal or requires repeated refinements to income documents, the 90‑day reservation window can expire, forcing the borrower to re‑apply and potentially miss the property. Conveyancers and brokers report that large originators like CBA have dedicated scheme‑processing teams that clear reservations within 48 hours, whereas smaller non‑banks occasionally take five to eight business days, creating settlement risk. The difference can be material for a buyer under exchange with a 42‑day settlement clause.
Servicing the 3% Buffer Under the Scheme’s Rules – The Math
APRA’s serviceability assessment approach is uniform across the panel because the guarantee does not alter the prudential requirement. The assessment rate for a borrower on a 6.50% variable mortgage is 9.50%; for a 3‑year fixed rate of 5.99%, the buffer applies over the roll‑off rate (the same 9.50% or a higher reversion rate), meaning no real reprieve. To understand where the effective cap sits for a given income, it is useful to unpack a simplified repayment table, acknowledging that lenders also add buffers for credit‑card limits, HEM adjustments, and proposed rent.
For a 30‑year P&I loan at an assessment rate of 9.50%:
| Loan Amount | Monthly Repayment at 9.50% | Annual Repayment | Approx. Required Gross Income (using 35% gross‑service ratio) |
|---|---|---|---|
| $600,000 | $5,043 | $60,516 | ~$173,000 |
| $700,000 | $5,884 | $70,608 | ~$202,000 |
| $800,000 | $6,724 | $80,688 | ~$231,000 |
| $900,000 | $7,565 | $90,780 | ~$259,000 |
These indicative gross income requirements assume no other debt and standard HEM. A single first‑home buyer earning $100,000 with a $30,000 deposit will be serviceable only up to about $550,000–$600,000, depending on HEM category, which pulls the Melbourne and Brisbane caps into reach but leaves Sydney well out. A dual‑income couple on $160,000 combined comfortably services $700,000 and may stretch to $800,000, making a Brisbane or Melbourne purchase achievable. For Sydney’s $900,000 cap, the couple needs north of $240,000 combined income under conservative serviceability, or must seek a lender that stretches DTI above 7x while still leaving a residual surplus.
The interaction with the DTI cap is mechanical: even if serviceability clears, the DTI limit of 7 times total income constrains the absolute loan size. On a $160,000 income, 7x yields $1,120,000 total borrowings, so a $900,000 loan is well within the limit if no other debts exist. The binding constraint in 2024 is almost always serviceability, not DTI, because the buffer rate shaves roughly 20% off the capacity that a simple DTI multiplication would imply.
Regional Price Caps and the Overlap with Other Guarantees
A separate scheme, the Regional First Home Buyer Guarantee (RFHBG), runs alongside the FHBG with its own higher caps. While not the focus of this article, its existence changes the calculus for buyers willing to look outside capital‑city markets. Housing Australia publishes separate price caps for RFHBG that are set at $900,000 for large regional centres including Newcastle, Geelong, the Gold Coast, and the Sunshine Coast, with a $750,000 cap for other regional areas. A buyer who qualifies for the RFHBG and is targeting a $850,000 home in Gold Coast can avoid the $700,000 FHBG ceiling entirely, and may find the 3% buffer less restrictive because the purchase price is lower than the Sydney equivalent. However, the RFHBG panel is more restricted, with only 27 lenders participating, and the property must be located within a designated regional area as defined by the Australian Statistical Geography Standard.
Builders and construction‑phase buyers face an added complexity. The FHBG does apply to newly constructed dwellings and off‑the‑plan purchases, but the guarantee is only valid if the building contract price is within the cap and if construction commences within six months of the reservation. Some panel lenders limit the LVR to 90% during the construction period, requiring a larger equity buffer until practical completion is certified. That nuance further erodes the theoretical capacity for a borrower who might otherwise think they can maximise the 95% LVR on a $900,000 house‑and‑land package in a Sydney fringe suburb.
Actionable Steps for a 2024 Application
For a borrower navigating the First Home Guarantee in the current rate and policy environment, four precise steps improve the odds of a signed contract:
- Pin the exact cap to the postcode, not the metro area. Use Housing Australia’s property lookup tool before browsing listings. Mistaking a $450,000 rest‑of‑state cap for a $600,000 capital‑city cap will eliminate an application at the document stage.
- Stress‑test borrowing capacity at the lender’s assessment rate, not the advertised rate. Ask the broker to run servicing at 9.50% (or 9.10% if targeting a low‑rate mutual) with your actual HEM category, credit‑card liabilities, and any HECS‑HELP debt. If the surplus is below $500 per month, the file will get scrutiny beyond the automated decision engine.
- Interview lenders for their DTI and buffer‑exception appetite before lodging. A major bank that hard‑caps DTI at 7x may be unsuitable for a couple pushing the Sydney cap on a $170,000 income; a mutual that will consider 7.5x with strong rental history and a 12‑month savings record could bridge the gap.
- Time the reservation to match the finance clause. The 90‑day guarantee reservation starts running from the date the place is allocated, not from unconditional exchange. Synchronise the application so the reservation is live for at least 60 days after the contract’s cooling‑off period ends,