How much can you borrow as a property investor under the new DTI rules?

Property investors now face Debt to Income (DTI) restrictions that limit how much banks can lend relative to your total household income. The Reserve Bank sets caps on how many high-DTI loans each bank can write, and within those caps, every lender applies different policies depending on their risk appetite, your deposit, your rental income treatment, and whether you are a new or existing customer. What you can borrow is not a fixed multiple anymore — it is a negotiation between your income structure, your equity position, and which lender is currently most open to investor lending.

I am JJ van der Westhuizen, a Senior Mortgage Adviser based on Auckland’s Hibiscus Coast, and I work with property investors across Auckland navigating exactly this question. The DTI framework has fundamentally changed how investors scale portfolios, and understanding the mechanics is the difference between a declined application and a structured growth plan.

What are DTI restrictions and how do they work for investors?

Debt to Income restrictions are a macroprudential tool the Reserve Bank introduced to limit household debt relative to income. For property investors, DTI measures your total proposed lending — including your home loan and all investment property debt — against your gross household income.

The Reserve Bank does not ban high-DTI lending outright. Instead, it sets a speed limit: each bank can only write a certain percentage of its new investor lending above a specified DTI threshold. That means some high-DTI lending is still possible, but it is rationed and competitive.

If you fall above that threshold, you are not automatically declined. You are competing for a slice of the bank’s high-DTI allocation. Banks prioritise that allocation based on deposit size, existing customer relationships, income quality, and portfolio risk. A borrower with significant equity and stable income has a much better chance than a highly leveraged applicant with variable income, even if both sit at the same DTI ratio.

This is why two investors with identical incomes can get wildly different answers from the same bank in the same month. One lands inside the speed limit, the other does not. One is an existing customer with offset accounts and term deposits, the other is brand new. Context drives outcome.

What income counts when calculating DTI for property investors?

Your DTI calculation includes all gross household income: salary, wages, self-employed income, and rental income from investment properties. How much of that rental income counts is where it gets complicated.

Banks do not count rental income dollar-for-dollar. They apply a haircut to account for vacancy, maintenance, rates, insurance, and property management. Some lenders assess rental income at a percentage of actual rent received. Others use a percentage of market rent if your property is tenanted below market. A few apply different percentages depending on whether the property is already in your portfolio or the one you are buying.

Self-employed income and contractor income face their own assessment rules. Most lenders average two years of net profit after tax, add back depreciation and interest, and may apply further discounts depending on industry and income trend. If your income is rising year-on-year, some lenders weight the most recent year more heavily. If it is falling, they take a conservative average or the lower year.

Bonuses, overtime, and commission income are treated differently depending on consistency and documentation. If you have received a bonus for three consecutive years, many lenders will include a percentage of it. If it is new or irregular, it may be excluded entirely.

The rental income and self-employed income treatment is where DTI outcomes diverge most between lenders. One bank might assess your rental portfolio generously and land you under the threshold. Another might haircut it heavily and push you over. This is not about dishonesty or optimism — it is policy difference, and it is why broker channel access to multiple lenders matters for investors.

How does your deposit and equity position affect DTI lending?

Your deposit or existing equity is the single biggest lever you have to offset a high DTI ratio. The more equity you bring, the more risk tolerance the bank has, and the more likely they are to allocate you one of their high-DTI slots if needed.

Investors with lower Loan to Value Ratios (LVR) — meaning larger deposits or more equity in existing properties — are prioritised for high-DTI lending. A borrower at a low LVR with a high DTI is a much safer bet than a borrower at a high LVR with a high DTI. The first has a capital buffer. The second is exposed on both fronts.

If you are at the margin of DTI serviceability, increasing your deposit even modestly can shift you from a decline to an approval. It reduces the debt side of the equation, improves your LVR, and signals commitment and financial discipline.

Equity from your existing home or investment properties can be used as deposit for the next purchase. But accessing that equity is itself subject to DTI assessment. If drawing down equity pushes your overall DTI above the threshold and the bank has limited high-DTI capacity, you may not be able to access all the equity you theoretically have available. This is a common frustration I see with Hibiscus Coast and wider Auckland investors who are equity-rich but income-constrained under the new settings.

Does rental income from the property you are buying count toward DTI?

Yes, but not always in the way you expect. The rental income from the property you are purchasing is included in your income assessment, but it is haircut just like your existing rental income, and some lenders are more conservative on new acquisitions than on properties you already own and have a tenancy history for.

If you are buying a tenanted property with a signed lease, the bank will assess that lease income, apply their haircut, and include it in your DTI calculation. If you are buying a vacant property and plan to rent it out, the bank will use a market rent assessment, apply a haircut, and include that.

The timing matters too. Some lenders include new rental income from day one in their DTI calc. Others phase it in or apply a higher discount until the property is tenanted and cash-flowing. If you are buying a property that needs minor work before tenanting, expect conservative treatment of that income until it is lease-signed and rent-banked.

This is why pre-purchase income modelling with an adviser is critical. If the rental income from the new property is needed to keep your DTI under the threshold, you need to know which lenders will treat that income favourably and which will not. Applying to the wrong lender first can burn time, cost you the deal, and leave a decline on your credit file.

How do existing investment properties affect your borrowing capacity under DTI?

Every existing mortgage you carry is added to the debt side of your DTI calculation. Every rental property you own contributes income to the income side, but only after the bank applies its haircut and expense assumptions.

If you own multiple investment properties, your DTI is cumulative. The bank is assessing your total debt servicing load across your entire portfolio, not just the new loan. This is a major shift from pre-DTI lending, where each property was often assessed more in isolation.

Investors with large portfolios and modest household salary income are the most impacted by DTI restrictions. Even if every property is positively geared and the portfolio cash-flows well, the gross debt quantum relative to income can push you over the threshold. In those cases, structuring matters: which properties are held in which names, whether a trust or company structure is involved, and whether spousal income is included all influence the calculation.

Some investors are now looking at portfolio restructure: selling one or two properties to reduce total debt, improve DTI, and then re-enter the market with a healthier ratio. Others are pausing acquisition and focusing on debt reduction or income growth. There is no one-size-fits-all answer, but ignoring your DTI position and hoping for the best is not a strategy anymore.

Which lenders are currently more open to investor lending under DTI settings?

Lender appetite for investor lending shifts constantly based on each bank’s high-DTI allocation, their portfolio composition, their funding costs, and their strategic priorities for the quarter. What is true in March may not be true in June.

Some lenders are more comfortable with high-DTI investor lending if you bring a large deposit and strong income documentation. Others are tightening across the board regardless of deposit. A few are prioritising existing customers and making it harder for new-to-bank investors to get high-DTI approval.

Non-bank lenders and second-tier lenders sometimes have different DTI settings or apply the rules with more flexibility, but often at a higher interest rate or with different fee structures. For some investors, paying a margin above main bank rates for 12 to 24 months to secure the property makes sense, with a plan to refinance once income or equity improves.

This is where a mortgage adviser earns their keep. I track which lenders are currently open, which are constrained, and which have policy nuances that suit specific investor profiles. Applying to the wrong lender first wastes time and can result in a decline that makes subsequent applications harder. Applying to the right lender first, with the right structure and documentation, maximises your chance of approval.

What can you do to improve your borrowing capacity as an investor under DTI rules?

If your DTI is marginal or over the threshold, you have several levers to pull, though none are instant fixes.

Increase your deposit or use more equity. This improves your LVR and reduces the debt side of the DTI equation. Even a modest equity injection can shift the numbers enough to land you under the threshold or make you a priority candidate for high-DTI allocation.

Increase your income or improve how it is assessed. If you are self-employed, work with your accountant to structure your income in a way that maximises what the bank can use. If you have variable income sources like bonuses or overtime, gather evidence of consistency. If your rental income is below market, consider re-tenanting at market rent before applying, so the bank assesses higher income.

Reduce non-mortgage debt. Credit cards, car loans, and personal loans all count against your servicing and indirectly affect DTI by reducing your effective income. Paying these down or off before applying can improve your position.

Consider joint applications carefully. Adding a partner or spouse with income can improve your DTI if their income is strong and their debt is low. But if they carry significant debt or have poor credit, it can hurt more than help. Run the numbers before deciding whether to apply solo or jointly.

Choose the right lender and structure upfront. This is not about shopping for the lowest rate. It is about identifying which lender’s policy settings align with your income structure, your portfolio, and your DTI position. An adviser who knows current lender appetite can save you months of frustration.

Key takeaways

• DTI restrictions limit property investor borrowing relative to total household income, with banks rationing high-DTI lending under Reserve Bank speed limits.
• Rental income is included in DTI calculations but is heavily discounted by lenders to account for vacancy, expenses, and risk.
• Your deposit and equity position is the biggest lever to improve DTI outcomes — larger deposits make you a priority for high-DTI allocation.
• Lender appetite for investor lending varies significantly and changes over time, making lender selection critical.
• Existing investment property debt is cumulative in your DTI calculation, meaning portfolio scale now directly constrains further borrowing unless income scales with it.
• Improving your DTI position requires a combination of deposit increase, income optimisation, debt reduction, and strategic lender choice.

Frequently asked questions

Can I still buy an investment property if my DTI is above the threshold?

Yes, but it is harder. Banks can still lend above the DTI threshold within their Reserve Bank allocation, and they prioritise borrowers with strong deposits, stable income, and existing relationships. You are not automatically declined, but you are competing for limited capacity.

Does rental income from my own home count if I rent out a room?

It can, but treatment varies. Some lenders will include boarder income if it is declared, consistent, and documented. Others exclude it or apply a heavy discount. If you rely on it to make your DTI work, check lender policy before applying.

Will paying down my mortgage improve my DTI for the next purchase?

Yes. Reducing your total debt directly improves your DTI ratio. If you are planning another purchase in the next year or two, accelerating mortgage repayment or making lump sum payments can improve your borrowing capacity under DTI settings.

Do DTI rules apply to refinancing my existing investment properties?

Generally no, if you are refinancing existing debt at the same or lower level. DTI restrictions primarily apply to new lending that increases your total debt. But if you are refinancing and increasing your borrowing, the increase is subject to DTI assessment.

Can I use a family trust to get around DTI restrictions?

Not really. Banks assess trust borrowing by looking at the income of the trust beneficiaries and settlors. If you are the effective borrower, your income and existing debt are still in the equation. Trusts can be useful for estate planning and asset protection, but they are not a DTI workaround.

How often do DTI thresholds and lender policies change?

Reserve Bank macroprudential settings are reviewed periodically, and individual bank policies shift quarterly or even monthly based on their lending volumes and risk appetite. What is possible today may not be possible in three months, and vice versa. Always work with current information.

Bank policies, DTI thresholds, lender appetite, and rental income assessment methods all shift over time. If you are a property investor working through your next purchase or refinancing your portfolio and want a current read on what is possible, get in touch. I work with investors across Auckland and the Hibiscus Coast to structure lending that fits both your goals and the current rules.

JJ van der Westhuizen (FSP1000031) is a Senior Mortgage Adviser operating under the FAP licence of Mortgage Design NZ Limited (FSP752291). This article is general information only and does not constitute personalised financial advice. Specific lender policies, government scheme thresholds, and interest rates change frequently — for advice tailored to your situation, please get in touch.