Market Power in Mortgage Pricing: the Role of Referral Lending

Despite intense competition among mortgage lenders, borrowers face substantial price dispersion. We argue that realtor–loan officer referral networks are a key source of lender market power: by steering homebuyers toward a small set of loan officers, these networks restrict effective borrower choice even in competitive markets. Using a novel dataset linking 81,306 realtors to 102,860 loan officers across 41 states, we document that such networks are pervasive and highly concentrated — 85% of realtors direct over 40% of their clients to fewer than four loan officers — and that this concentration persists and even increases in markets with more lenders. IV estimates indicate that borrowers using referred loan officers pay 18.6 basis points higher mortgage rates, equivalent to $2,609 in upfront costs on the average loan of $306K. Referral lending raises rate spreads by 36.5% and accounts for half of the residual cross-sectional variation in spreads. The premium is nearly three times as large for Hispanic borrowers as for White borrowers, and is systematically higher for Black borrowers and financially constrained households. We identify two channels: referrals reduce borrowers' search intensity across lenders, and referred loan officers exercise pricing power relative to colleagues within the same institution. Efficiency gains from faster processing and reduced denial risk do not offset the additional costs.