Typically lenders won?t rely on Rental income in isolation and they will look for an alternate source as well (could be regular full-time employment, investment income etc) . Where a majority of a borrower?s income is derived from rental income and serviceability is heavily reliant on that amount, the application may be considered too rent reliant.
Lenders? scoring models often treat rental income differently to regular full-time employment. For example Permanent Full-time employment is treated as 100% of serviceable income ($100k x 100% = $100k) while rent income is treated as 80% of serviceable income ($100k x 80% = $80k). This value will change from one lender to another.