Debt recycling, explained

Debt recycling is one of those AU-specific strategies that sounds clever in a podcast and turns out to be either brilliant or disastrous depending on how it's executed and how you handle a bad market.

I've used a version of it. I've watched a mate get burned by a more aggressive version of it. Here's the honest mechanic.

The basic idea

In Australia, interest on debt used to invest is tax-deductible. Interest on debt against your home is not.

Debt recycling exploits this. You pay down your home loan, then re-borrow the equivalent amount and invest it (in ETFs, typically). The total debt stays the same, but its character has shifted from non-deductible to deductible.

Over time, you "recycle" your non-deductible mortgage debt into deductible investment debt while building an investment portfolio alongside.

The mechanic, step by step

You need a few things in place first:

• A home loan with an offset account or a redraw / split facility
• A separate, unencumbered investment loan facility (or the ability to split off a portion of your home loan)
• A brokerage account in your name (or a structure if you're using a trust)
• Surplus cash flow each month

The flow:

• You make your normal mortgage repayments
• Above and beyond that, you put extra cash into the home loan, paying it down faster
• Once you've paid down, say, $10,000 of the principal, you re-borrow that $10,000 from a separate split account
• You invest the $10,000 into ETFs
• The interest on the $10,000 split is now deductible (because it's investment debt)
• You repeat the cycle every month or quarter

Total debt: unchanged. Tax-deductible portion of debt: growing. Investment portfolio: growing.

The maths, with sober assumptions

Say you've got a $600,000 home loan at 6%, on a $90k income (37% marginal rate). You've got $1,500/month surplus you'd otherwise stick into the offset.

Without debt recycling: $1,500/month off the loan. Mortgage paid off ~7 years sooner. No investment portfolio.

With debt recycling: $1,500/month into the loan, then re-borrowed and invested. Same mortgage payoff timeline (because you're not actually reducing the loan balance, you're just changing its character). But you've built a $180k+ investment portfolio over ten years (before market growth) that's compounding alongside.

The tax benefit: 6% interest on $180k of deductible debt = $10,800 of deductions per year, worth $4,000 to you at 37% marginal. That's $4k a year of tax saved that wasn't being saved before.

The investment growth: a 7% real return on the portfolio compounding alongside means you've also got $250k+ of equities in ten years.

The headline pitch: same debt, same monthly outflow, but now you've got a six-figure portfolio AND a tax saving.

Where it goes wrong

The pitch is real. So are the risks.

Investment performance risk. You're borrowing to invest. If the market falls 30% in year three, your $180k portfolio is now $126k, but your $180k of investment debt is still $180k. You're underwater on the investment leg. The maths assumes long-run returns above the cost of debt. Over 30 years, that's likely. Over any 5-year window, no guarantee.

Interest rate risk. Rates moved from 2% to 6% in two years recently. If your debt is variable, your interest cost just tripled. Your investment returns probably didn't.

Behavioural risk. Watching your investment portfolio drop while still paying interest on the debt that funded it is psychologically brutal. People panic-sell at the bottom and crystallise losses, while the debt stays.

Cash flow risk. If you lose your job, you've still got the same total debt servicing requirement. Selling the investments to clear the debt locks in whatever the price is that day.

Structural risk. If the loan splits aren't set up cleanly, the ATO can deny the deductibility of the interest. The "purpose test" matters. Get the structure wrong and the whole strategy is broken.

The structure that actually works

Talk to a mortgage broker who's done this before. The cleanest setup is:

• Main home loan (non-deductible, you pay it down aggressively)
• Separate investment loan or split account, with its own loan number, that's only ever used to fund investments
• Investments held in your name (or trust) at a brokerage that's separate from the loan
• Clear paper trail: every dollar drawn from the investment split goes to investments, never anywhere else

Mixing the purposes (using the investment split to also pay personal expenses) destroys the deductibility. The ATO has been very clear on this.

When it makes sense

• High marginal tax rate (37% or 47%) so the deduction is worth something
• Stable income, low risk of needing to liquidate quickly
• Long investment horizon (15+ years)
• Strong behavioural temperament (you can sit through a bear market without selling)
• Clean loan structure with separate splits
• Ability to absorb a 30%+ paper drawdown in your investments without cash flow stress

When it doesn't

• Low or unstable income
• Short timeline before you'd need to access the money
• High existing debt levels (don't add more debt to a stretched balance sheet)
• Behavioural panic-seller (be honest with yourself)
• Recent divorce, job change, or major life uncertainty (defer this until things stabilise)

My own approach

I've debt recycled at a moderate pace. Not aggressively. The combination of a property portfolio, an ETF portfolio, and a paid-down PPOR was already enough exposure to leveraged growth assets. Adding another aggressive layer felt like courting fragility.

The version I've used: a small, clean split off the home loan, used purely for ETFs, recycled gradually as I paid the main loan down. The deduction is meaningful. The exposure is modest. The structure is clean.

Some people run it harder. Bigger splits, faster recycling, more concentrated portfolios. The upside is bigger and so is the downside.

The thing nobody mentions

Debt recycling looks brilliant during a long bull market. Anyone who started it in 2010 has been a genius for fifteen years. The strategy hasn't been seriously tested by a sustained bear market plus high rates plus a recession. It will be, eventually.

Build for the bad scenario. If you can't survive it, don't enter it.

If the strategy collapses the moment markets fall and rates rise, the strategy was never the strategy. The bull market was.

Borrow carefully. Compound patiently. Survive first.

Not financial advice, talk to an adviser before acting.