Using loan-level foreclosure auction data we study the loss given default (LGD) of defaulted residential mortgages originated in Korea, a low LTV regime. We find that senior mortgages generate very low loss rates (5–10%) while losses of subordinated claims are in 30–50% range. We document the effects of housing market cycles on loss severity by showing that collateral characteristics that are overvalued during the boom increase loss severity during the market downturn. We also investigate how a broad set of time-of-origination and post-origination information on loan, collateral and borrower characteristics and foreclosure auction process influence the LGD of residential mortgages.