Skip to content

Building a Property Portfolio: The Strategy Most Investors Get Wrong

I’ve spoken with hundreds of property investors over the years, and the most common pattern I see is this: someone buys their first investment property, it goes well, they decide to buy a second — and suddenly their borrowing capacity is gone. The equity is there, but the banks won’t lend any more.

This isn’t bad luck. It’s the result of starting with the wrong finance structure. Let me explain how to avoid it.

Investment property building a portfolio
The investors who build large portfolios don’t necessarily earn more — they structure their debt differently from the start.

The Core Problem: Cross-Collateralisation

Many investors — especially those using the same bank for multiple properties — end up with their properties cross-collateralised: the bank uses all your properties as security for all your loans. This makes refinancing, selling, or accessing equity in one property enormously complicated because the bank has a claim over everything.

Smart portfolio builders structure each property with a standalone loan wherever possible, and use a mortgage broker who specialises in investment lending to manage the overall structure.

The Equity Ladder

The mechanism for building a portfolio is the equity ladder:

  • Buy Property 1 with a 20% deposit
  • Property 1 grows in value — your equity position increases
  • You access that equity via a Line of Credit or refinance to use as a deposit for Property 2
  • Repeat

The critical point: you need to manage your borrowing capacity across each step. High-yield properties early in your portfolio help maintain serviceability as you add more debt.

Building a multi-property portfolio in Australia — the strategy explained

Where a Buyers Agent Adds the Most Value in Portfolio Building

Your first purchase sets the trajectory for your entire portfolio. A property that underperforms in year one means you have less equity to draw on for the second purchase, and your portfolio compounds more slowly from there.

The investors I’ve seen build the largest portfolios almost always engaged a buyers agent for their first purchase. Not because they couldn’t find a property themselves — but because they wanted to start with the best possible asset and the right structure.

Before you start looking, get your finance in order. Read my full guide on how to finance your first investment property in Australia — and understand how the RBA rate cycle will affect your borrowing capacity over the life of your portfolio.

Sources: APRA | RBA | CoreLogic | ATO