The Interaction of Borrower-Targeted Macroprudential Tools in the Irish Mortgage Market: A Baseline Multi-Agent Approach

Lax credit conditions and speculative behaviors can combine to bring about leveraged real estate bubbles that pose a threat to financial stability. This risk can be pushed away by the adoption of proper macroprudential polices. Borrower-based macroprudential tools, namely loan-to-value and debt-to-income ratios, are designed to dampen the procyclicality of credit and to enhance the resilience of financial institutions. By putting a ceiling to borrowing the financial sustainability of mortgages can be improved for borrowers and lenders. This paper studies the interaction of the two instruments employing an agent-based model calibrated on the Irish mortgage market. I construct several policy scenarios grounded on residential loan data to run counterfactual experiments and explore alternative settings of macroprudential policy. This approach provides granular artificial data about the distribution of loan-to-value and debt-to-income ratios at origination, credit, and house prices.