APRA's decision comes in response to a noticeable increase in high DTI lending, which poses potential risks to both borrowers and the broader financial system. By imposing this cap, APRA aims to mitigate the accumulation of excessive household debt and promote prudent lending practices among financial institutions.

For prospective borrowers, this policy change means that obtaining a mortgage with a high DTI ratio may become more challenging. Lenders are likely to tighten their assessment criteria to comply with the new regulations, potentially requiring borrowers to demonstrate stronger financial positions or seek lower loan amounts relative to their incomes.

Existing borrowers with high DTI ratios should also be aware of the implications. While the cap applies to new lending, it reflects a broader regulatory focus on financial stability. Borrowers may benefit from reviewing their financial situations and considering strategies to reduce their debt levels, such as consolidating existing debts or increasing repayments to lower their DTI ratios.

In summary, APRA's introduction of a 20% cap on high DTI mortgages is a proactive step towards safeguarding the Australian housing market. Both new and existing borrowers should stay informed about these changes and consider how they might impact their financial decisions.