银行是否为抵押贷款发放中的洪水风险定价：来自新奥尔良自然实验的证据

Federal Reserve Board, Washington, D.C.ISSN 1936-2854 (Print)ISSN 2767-3898 (Online) Do Banks Price Flood Risk in Mortgage Origination: Evidencefrom a Natural Experiment in New Orleans David M. Arseneau and Gazi I. Kara 2025-081 Please cite this paper as:Arseneau, David M., and Gazi I. Kara (2025).“Do Banks Price Flood Risk in MortgageOrigination: Evidence from a Natural Experiment in New Orleans,” Finance and EconomicsDiscussion Series 2025-081. Washington: Board of Governors of the Federal Reserve System,https://doi.org/10.17016/FEDS.2025.081. NOTE: Staff working papers in the Finance and Economics Discussion Series (FEDS) are preliminarymaterials circulated to stimulate discussion and critical comment.The analysis and conclusions set forthare those of the authors and do not indicate concurrence by other members of the research staff or theBoard of Governors. References in publications to the Finance and Economics Discussion Series (other thanacknowledgement) should be cleared with the author(s) to protect the tentative character of these papers. Do Banks Price Flood Risk in Mortgage Originations?Evidence from a Natural Experiment in New Orleans∗ David M. Arseneau and Gazi I. Kara Federal Reserve Board September 8, 2025 Abstract This paper uses a large-scale redrawing of flood zone maps for the City of New Orleansin 2016 to identify how banks respond to changes in perceived flood risk in residential mort-gage origination. Using geo-coding, we separate loan-level data on mortgage originations intotreatment versus control groups based on how individual properties were affected by the mapchanges. We find banks charged interest rates that were roughly 6 basis points higher for mort-gages on treated properties that were removed from the special floods zones as a result of themap changes. In addition, lower loan-to-value ratios for mortgages on these properties suggestthat banks also required higher downpayments. Both effects are temporary, lasting under twoyears.Further analysis using flood insurance claims data following a major flooding event in2017 suggests the temporary nature of these effects may reflect learning by banks about thetrue extent of flood risk and insurance take-up following the map changes. Keywords:FEMA Maps, Flood insurance, Mortgage lendingJEL Classifications:G21; Q54; R3 1Introduction The U.S. residential real estate market is supported by approximately$14 trillion in mortgagedebt, making it the largest non-sovereign debt market in the world. A sizeable proportion of thisactivity is intermediated through the banking system.Accordingly, residential mortgages makeup a substantial share of assets held on bank balance sheets and are a significant source of riskexposure. This paper contributes to the literature on how banks monitor and price risk by focusingon flood risk in the context of a unique natural experiment involving the large-scale redrawingof Federal Emergency Management Agency (FEMA) flood maps for Orleans Parish, Louisiana in2016.1In doing so, we provide novel insights into banks’ risk management practices and theirability to adjust loan pricing in response to changes in perceived flood risk. Prior to the 2016 redrawing, a large portion of properties in the parish were located in specialflood hazard areas (SFHAs), meaning that owners of these properties were required to purchasefederal flood insurance if their mortgages government-backed or from a federally regulated lender.Following the completion of flood protection infrastructure in the wake of Hurricane Katrina, whichdevastated New Orleans in 2005, city officials successfully lobbied FEMA to reconsider the bound-aries that delineate the SFHAs in a large-scale redrawing of the flood maps.The redrawn mapswere announced in early-2016 and went into effect later that year. The map changes resulted in theremoval of roughly half of all properties in the parish from the special floods zones, implying thatmortgage borrowers for these properties were no longer required to purchase flood insurance whenfinancing their homes. Existing literature has shown that when flood insurance is not mandated,homeowners have a difficult time assessing their vulnerability to flood risk and often simply choosenot to purchase flood insurance or they let existing policies lapse.2 This paper empirically examines the extent to which banks altered mortgage lending terms inresponse to perceived changes in the risk profile of individual properties affected by these mapchanges. From the lenders’ point of view, the map changes could have affected the risk profile ofa treated property in two potentially competing ways.On the one hand, the fact that a givenproperty was removed from the SFHA suggests that it ought to be less flood prone and hence lessrisky.This is true provided the map changes implemented by FEMA accurately reflect evolvingflood risk. While this is likely the case at the aggregate level, given the scale of the changes, the newflood