Smart timing your move from alt‑doc to full‑doc finance

Self‑employed borrowers usually start with alt‑doc or low‑doc because their lodged tax returns lag behind their real income. Upgrading to full‑doc makes sense once your numbers catch up, but if you mistime it you can increase repayments and strain both your business and home cashflow.

This guide shows when the move from alt‑doc to full‑doc is worth it, how to check if now is the right time, and a step‑by‑step upgrade plan that protects your cash buffer.

Quick answer: when should you move from alt‑doc to full‑doc?

In plain English, it’s usually time to move from alt‑doc to full‑doc when:

1. Your last 1–2 years of lodged tax returns show stable or rising taxable income.
2. Your business has at least 12–18 months of consistent revenue at the new level.
3. You hold 2–3 months of living costs in your personal buffer and 1–2 months of business overheads in the business (not in redraw or credit cards).
4. The interest savings from full‑doc are clearly bigger than any increase in repayments from switching product type or shortening the term.

If you’re not sure, your first step is to model both your borrowing capacity and post‑refinance repayments before you lodge new tax returns or change anything else.

Alt‑doc vs full‑doc: what actually changes?

Before you decide when to upgrade, you need to be clear on what you’re upgrading from and to.

What is an alt‑doc home or investment loan?

Alt‑doc (or alternative documentation) loans are designed for self‑employed borrowers whose paperwork isn’t yet full‑doc ready, but whose real income supports the loan. Instead of two years of tax returns, lenders might accept:

• Accountant’s declaration
• Business Activity Statements (BAS)
• Business bank statements
• A combination of the above

In return for this flexibility, you normally face:

• Higher interest rates than mainstream full‑doc
• Stricter LVR caps (often 70–80% max) and tighter cash‑out rules
• Fewer lenders and less product choice

Alt‑doc is often a bridge, not a forever home – a theme we dig into in more detail in /insights/choosing-full-doc-alt-doc-low-doc-alexandria-self-employed.

What is a full‑doc loan?

Full‑doc loans are the standard products most PAYG borrowers use. For self‑employed borrowers, full‑doc usually means:

• Lodged personal tax returns (and business returns where relevant) for the last 1–2 years
• Notices of Assessment from the ATO
• Financial statements for the business (company, trust, partnership)

In return, you usually get:

• Sharper interest rates
• Higher LVRs and more flexible equity release
• Wider lender and product choice (offset, packages, IO/P&I options)

Typical trade‑offs: alt‑doc vs full‑doc

Here’s a simplified comparison using indicative figures only (not live offers):

On a $900,000 loan, a 1.0% rate difference is worth about $9,000 per year in gross interest. That’s why timing the upgrade matters.

Step 1 – Check the real benefit: rates vs cashflow

A lot of self‑employed borrowers assume that moving to full‑doc is always cheaper. It’s not always that simple, especially in a higher‑rate environment where 32.5% of Aussie borrowers are already in mortgage stress (Roy Morgan, July 2026).

Run the numbers on repayments

Use a simple example to see how upgrades can help or hurt cashflow.

Assume:

• Current alt‑doc loan: $900,000
• Remaining term: 27 years
• Interest rate: 7.5% p.a.

Approximate monthly repayment (P&I) ≈ $6,720.

Now you refinance to full‑doc:

• New interest rate: 6.1% p.a. (1.4% lower)
• New term: 30 years (reset)

New monthly repayment ≈ $5,423.

That’s a saving of around $1,300 per month in repayments. Over the first year, that’s $15,600 in gross cashflow relief.

But there are traps:

• If you shorten the term to 20 years while you refinance, repayments jump.
• If you pay off other debts in the refinance (e.g. credit cards, tax debt), your single mortgage repayment might go up, even though your total interest cost falls.

The safe way is to model both:

1. Cashflow view – are your monthly repayments lower, the same, or slightly higher?
2. Lifetime cost view – how much total interest will you save over the life of the new loans?

Our article on refinancing strategy lays this out in more detail: /insights/refinancing-low-doc-to-full-doc-timeline-traps-tactics.

Decide your priority: lower repayments vs faster payoff

Be honest about what you need in the next 3–5 years:

• If your business is growing but lumpy, you usually prioritise cashflow and buffers. That might mean similar or lower repayments at a better rate.
• If your income is stable and you’re ahead, you might keep repayments the same but cut the term and debt faster.

In a world where one or two bad quarters can derail a small business, most self‑employed clients choose to protect cashflow first, then make extra repayments when cash is strong.

Step 2 – Make sure your tax returns help, not hurt

Lodging tax returns is often the biggest trigger for moving from alt‑doc to full‑doc – and also the most common own‑goal.

How lenders use your tax returns

For self‑employed borrowers, most full‑doc lenders will:

• Look at your last two years of lodged tax returns
• Calculate income using the lower year or an average, with add‑backs where policy allows
• Apply a 3% serviceability buffer above the actual rate (APRA guidance)

That means if you:

• Over‑minimise taxable income to save tax, or
• Have one year much lower than the other

…your borrowing power can drop sharply, sometimes more than you saved in tax.

We walk through this dynamic in detail – especially for Mascot‑area buyers – here: /insights/timing-tax-returns-self-employed-mascot-home-buyers.

Worked example: tax vs borrowing power

Assume you:

• Made $260,000 true profit last year
• Your accountant suggests claiming extra deductions to bring taxable income down to $170,000

That might save, say, $30,000 in tax. But for a lender, the difference between assessing $260,000 and $170,000 might cut your borrowing capacity by $300,000–$500,000+, depending on your other debts.

If you’re about to buy or refinance, that trade‑off needs to be conscious, not accidental.

Coordinate broker and accountant before you lodge

Before lodging:

1. Ask your broker for capacity numbers on a few draft income scenarios.
2. Ask your accountant for the tax impact of each scenario.
3. Decide together what level of taxable income gives you enough borrowing power without paying more tax than necessary.

If your returns are already lodged and they’re low, you may need a 12–24 month plan to lift taxable income to a level that supports a full‑doc refinance.