Sydney may not be Australia’s capital, but it is the capital of Australian investor housing debt.

By some margin, too.

Here’s the proof, courtesy of Macquarie Bank.

Macquarie Bank

It shows the proportion of outstanding investor housing debt nationally by individual capital city in the 2015/16 financial year.

Sydney stood head and shoulders above the remaining capital cities, including Melbourne, reflecting not only that it is Australia’s largest and most expensive housing market, but also by the popularity of housing investment in the city.

While the data is undoubtedly dated, it gives a broad indication of what’s owed where across the capital cities.

According to the ABS, the outstanding value of investor housing debt nationally owed to Australian authorised deposit-taking institutions (ADIs) stood at $533.8 billion as at June 30, 2016.

Since then, that figure has risen $565.4 billion as at July this year.

Following the introduction of restrictions on interest-only lending by Australia’s banking regulator, APRA, back in March 2017, limiting the proportion of interest-only lending to 30% of new loans, it has meant some interest-only borrowers have been forced to switch to amortising loan repayments, increasing monthly payments.

Interest-only loans were popular with investor borrowers given the tax advantages through negative gearing.

Given the concentration of outstanding investor loans in Sydney, and the higher home loan repayments for some investor borrowers, it explains why some are concerned recent changes could lead to an increase in bad debts and potential forced sales.

Business Insider Emails & Alerts Site highlights each day to your inbox. Email Address Join

Follow Business Insider Australia on Facebook, Twitter, LinkedIn, and Instagram.