We shed new light on the role of borrower characteristics in mortgage product choice, and how these are impacted by regulatory capital requirements. Using rich loan-level data from the Australian market we analyse the borrower idiosyncratic risk e ects on the choice between variable-rate mortgages (VRMs) and other mort- gages with reduced initial payments. We nd that income, wealth and mobility risks play a role in product choice. We investigate regulatory capital requirements in a market where banks hold mortgage risk on-balance sheet and nd that the Basel capital discounts based on LTV ratios divide otherwise similar borrowers in their mortgage choices.