Do Credit Conditions Move House Prices?

Overview

Research Question. To what extent did an expansion and contraction of credit drive the 2000s housing boom and bust? The existing literature offers sharply divergent answers — ranging from credit explaining virtually none of the boom (Kaplan, Mitman, and Violante 2020) to credit explaining the majority of it (Favilukis, Ludvigson, and Van Nieuwerburgh 2017, who find credit alone explains 60% of the rise in price-to-rent ratios). Greenwald and Guren argue that the source of these divergent findings is a single structural assumption: the degree to which credit-insensitive agents (landlords and unconstrained savers) can absorb credit-driven demand for housing, which in turn depends on the degree of segmentation between the owner-occupied and rental housing markets.

Key Mechanism. The paper organizes the literature around a “tenure supply” curve, defined in price-rent ratio versus homeownership rate space. A perfectly inelastic (vertical) supply curve — corresponding to perfect segmentation, in which housing cannot move between the owner-occupied and rental sectors — implies that credit expansion bids up house prices with no change in the homeownership rate. A perfectly elastic (horizontal) supply curve — corresponding to a frictionless rental market with deep-pocketed landlords who price at the present value of rents — implies that credit expansion raises the homeownership rate but not the price-rent ratio, because landlord reservation prices are unaffected by credit. Intermediate degrees of segmentation produce intermediate outcomes: credit raises both the price-rent ratio and the homeownership rate, with the relative magnitudes determined by the slope of the tenure supply curve.

Empirical Strategy. To measure where reality falls on this spectrum, the authors estimate the relative elasticity of the price-rent ratio to an identified credit supply shock, compared to the elasticity of the homeownership rate to the same shock. This ratio is a sufficient statistic for the slope of the tenure supply curve. They use three distinct identification strategies from prior literature — (1) Loutskina and Strahan (2015), instrumenting for local credit supply using differential city-level exposure to changes in the conforming loan limit (CLL); (2) Di Maggio and Kermani (2017), exploiting the 2004 OCC preemption of state anti-predatory-lending laws for national banks; and (3) Mian and Sufi (2019), using differential city-level exposure to the 2003 private label securitization (PLS) expansion through bank funding composition. Regressions are estimated on annual CBSA-level panels using local projection IV (LP-IV) or event-study reduced-form methods. Key data include the CoreLogic repeat-sales house price index, the CBRE Torto-Wheaton same-store rent index (a repeat-rent index for multi-unit apartment buildings, constructed from newly-leased units), and Census Housing Vacancy Survey homeownership rates.

Main Empirical Findings. All three instruments consistently find that credit supply shocks generate a significant increase in house prices and the price-rent ratio but a much smaller, rarely statistically significant, effect on the homeownership rate. Under the LS LP-IV, the price-rent ratio peaks at an increase of 0.471, while the homeownership rate response reaches only 0.037 at the 2-year horizon and peaks at 0.101 after 5 years. The ratio of price-rent to homeownership responses ranges from 3 to infinity across the three instruments and horizons. These estimates imply a substantial degree of segmentation — the no-segmentation model falls far outside the 95% confidence intervals at all horizons.

Structural Model and Calibration. The authors construct a general equilibrium model featuring a representative borrower, landlord, and saver, with long-term fixed-rate mortgages subject to loan-to-value (LTV) and payment-to-income (PTI) limits following Greenwald (2018). The key modeling innovation is within-type heterogeneity in the benefit of owning versus renting, captured by logistic distributions for both borrowers and landlords. The dispersion parameter of the landlord distribution (σω,L) governs the slope of the tenure supply curve and is calibrated to minimize weighted distance to the LS empirical impulse responses. The resulting benchmark calibration yields σω,L = 2.877, with the benchmark model’s price-rent-to-homeownership ratio between 6.98 and 9.31 depending on the horizon — consistent with the empirical estimates.

Quantitative Results on the 2000s Boom. The paper then uses the calibrated model to simulate a credit standard relaxation (LTV limits relaxed from 85% to 99%, PTI limits from 36% to 65%) from 1998 Q1 through 2007 Q1, with a reversion at the start of the bust. This credit relaxation alone explains 34% of the peak rise in price-rent ratios observed in the boom, with a lower bound of 26% accounting for parameter uncertainty. In contrast, the no-segmentation model explains -1%, while the full segmentation model explains 38%. Adding a 2 percentage point permanent decline in mortgage spreads alongside the credit standard relaxation allows the benchmark model to explain 72% of the observed rise in price-rent ratios and 80% of the rise in loan-to-income ratios, compared to only 4% in the no-segmentation model. In a “full boom” scenario where additional demand and supply shocks are added to match the entire boom in price-rent ratios and homeownership, removing the credit relaxation reduces the rise in price-rent ratios by 55% in the benchmark economy — larger than the 34% explained in isolation due to nonlinear interactions — compared to only 5% in the no-segmentation economy.

Scope Conditions and Extensions. These results apply to the benchmark calibration in which landlords do not use credit and saver housing demand is fixed. When landlords are allowed to use credit (LTV limit of 65% relaxed to 85% during the boom), the role of credit is strengthened: the recalibrated model explains 80% of the rise in price-rent ratios from combined credit and rate changes, suggesting the benchmark is a lower bound. When savers are allowed to frictionlessly trade housing with borrowers, credit explains 54% of the rise in price-rent ratios even after recalibration — a roughly 25% reduction relative to the benchmark 72%, representing what the authors characterize as an extreme lower bound given that saver housing markets are in practice substantially segmented due to indivisibility, quality, and location differences.

Policy Implications. The findings imply that macroprudential policies tightening LTV and PTI ratios can be effective at restraining house price growth, but only in the presence of the significant rental market segmentation found in the benchmark economy. In the no-segmentation economy, removing the credit relaxation from the full boom reduces price-rent ratio growth by only 5%.

Q&A

Q1: What is the core theoretical insight that reconciles the divergent findings in the prior literature on credit and house prices?

The key difference is the degree to which credit-insensitive agents — specifically landlords and unconstrained savers — can absorb credit-driven demand for housing. Models with perfectly segmented rental markets (no rental sector or fixed homeownership rate) feature borrowers competing only with each other for a fixed stock, so credit expansion bids up prices. Models with frictionless rental markets feature deep-pocketed landlords who supply housing at a price equal to the present value of rents, which is unaffected by credit; credit expansion then raises the homeownership rate rather than prices. Intermediate degrees of frictions produce intermediate outcomes. This mechanism had not been recognized as the source of the literature’s divergence before this paper.

Q2: What is the “tenure supply curve” and why is its slope the key empirical object?

The tenure supply curve describes the menu of price-rent ratios at which landlords are willing to supply varying amounts of owner-occupied housing (given total housing stock), traced out in price-rent ratio versus homeownership rate space. Its slope determines how the equilibrium responds to a credit-induced demand shift: a steep (inelastic) supply curve translates credit expansion primarily into price-rent ratio increases; a flat (elastic) supply curve translates it primarily into homeownership rate increases. Identifying this slope empirically is therefore sufficient to discipline any macro-housing model’s predictions about the role of credit in price dynamics, for arbitrary underlying shocks.

Q3: How do the authors identify the slope of the tenure supply curve empirically?

They estimate the slope as the ratio of the causal elasticity of the price-rent ratio to that of the homeownership rate, with respect to an identified credit supply shock. Three instruments are used: (1) the Loutskina-Strahan shift-share instrument based on differential exposure to changes in the conforming loan limit, estimated by LP-IV on an unbalanced panel of 62 CBSAs from 1992 to 2016; (2) the Di Maggio-Kermani event study based on the 2004 OCC preemption of state anti-predatory-lending laws, covering 262 CBSAs for house prices and 82 CBSAs for homeownership from 2001 to 2010; and (3) the Mian-Sufi event study based on differential exposure to the 2003 PLS expansion via non-core deposit share, covering 245 CBSAs using ACS and FHFA data. In practice, they estimate the inverse slope (ratio of homeownership to price-rent response) because the first stage is far stronger using price-rent ratios as the endogenous variable.

Q4: What are the empirical results on the relative price-rent and homeownership responses?

Across all three instruments, credit supply shocks significantly raise the price-rent ratio but have a much smaller, rarely statistically significant effect on the homeownership rate. Under the LS LP-IV, the price-rent ratio peaks at 0.471 after 2 years, while the homeownership rate reaches only 0.037 at 2 years and peaks at 0.101 at 5 years. The naive point-estimate ratios range from 2.93 to 12.83 at horizons 2 through 5, with the 4-year estimate negative (implying an infinite slope). The directly estimated inverse slope coefficients are small (0.05 to 0.24) and never statistically different from zero. The DK instrument yields slopes of 6.72 in 2005, 3.67 in 2006, and 3.40 in 2007. The MS instrument yields a slope of approximately 4.49 in both 2006 and 2007. The lower bound of the 95% confidence intervals corresponds to slopes of at least 1.8 to 8.4.

Q5: What is the key modeling contribution on the structural side?

The key innovation is the introduction of within-type heterogeneity in ownership preferences for both borrowers and landlords, modeled as logistic distributions. This heterogeneity allows the model to generate a fractional and time-varying homeownership rate — a feature absent from most prior macro-housing models — and maps directly into the slopes of the demand and tenure supply curves. The dispersion in landlord ownership costs (σω,L) governs the supply curve slope and is calibrated to match the empirical impulse responses. Without this heterogeneity, the model would produce corner solutions with all housing owned by one type.

Q6: How is the landlord dispersion parameter σω,L calibrated, and what is the estimated value?

The calibration minimizes a weighted sum of squared deviations between model and data impulse responses for the price-rent ratio and homeownership rate, using the LS LP-IV estimates. Deviations are weighted by the inverse of empirical standard errors. Because model impulse responses jump on impact while empirical responses are hump-shaped (due to search frictions), the calibration uses only horizons 2 through 5 years. The minimum-distance estimate yields σω,L = 2.877, alongside a mortgage spread shock persistence of 0.965 and a shock size of -0.041 (corresponding to an annualized CLL subsidy of approximately 17 basis points, within the 10-24bp range found in prior literature). The benchmark model’s implied price-rent-to-homeownership response ratio ranges from 6.98 to 9.31, consistent with the empirical estimates.

Q7: What lower bound does the paper derive for σω,L, and how does the no-segmentation model compare?

A credible set for σω,L is derived by targeting the upper and lower bounds of the 95% confidence interval for the estimated inverse slope. The lower bound for σω,L (targeting the top of the confidence interval) is 0.810; the lower bound targets the bottom of the confidence interval but is best matched by the full segmentation case (σω,L → ∞). The no-segmentation economy (σω,L = 0) produces inverse ratios between 4 and 32 times the empirical upper bound, placing it far outside the credible set.

Q8: What is the model’s quantitative finding on the role of credit standard relaxation in isolation?

A credit standard relaxation (LTV from 85% to 99%, PTI from 36% to 65%) implemented from 1998 Q1 to 2007 Q1 and then reverted explains 34% of the peak rise in price-rent ratios in the benchmark model, with a lower bound of 26% conditional on parameter uncertainty. In the full segmentation model, the same relaxation explains 38%, while in the no-segmentation model it explains -1%. Credit standard relaxation also explains 51% of the rise in loan-to-income ratios in the benchmark, compared to 31% in the no-segmentation model.

Q9: What does adding a decline in mortgage rates contribute?

Adding a permanent 2 percentage point decline in mortgage spreads alongside the credit standard relaxation increases the benchmark model’s explained share of the price-rent ratio boom from 34% to 72%, and the loan-to-income ratio share from 51% to 80%. The no-segmentation model explains only 4% of the price-rent ratio boom and 38% of the loan-to-income ratio boom under the same combined experiment.

Q10: How does the “full boom” counterfactual estimate the marginal contribution of credit?

The full boom experiment adds exogenous demand shocks (shifts to µω,B) and supply shocks (shifts to µω,L) on top of the credit relaxation and rate decline, calibrated to exactly reproduce the observed peak increase in both the price-rent ratio and the homeownership rate during the boom. Removing the credit relaxation from this full boom scenario reduces the rise in price-rent ratios by 55% and the rise in loan-to-income ratios by 74% in the benchmark economy. This exceeds the 34% figure from the credit-alone experiment due to strong nonlinear interactions: without the credit relaxation, binding PTI limits constrain households’ ability to finance properties even when ownership preferences rise, dampening both price and credit growth. In the no-segmentation economy, removing the credit relaxation reduces price-rent ratio growth by only 5%.

Q11: What are the implications of allowing landlords to use credit?

When landlords face an LTV limit of 65% relaxed to 85% during the boom, the credit expansion also shifts the tenure supply curve upward (as in Panel (d) of the supply-demand framework), leading to a larger price-rent ratio response and a smaller homeownership rate response than in the baseline. Without recalibration, this model explains 81% of the price-rent ratio rise. After recalibration of σω,L (which is required because landlord credit changes the mapping from empirical moments to structural parameters), the model explains 80% of the price-rent ratio rise. This implies the benchmark results are a lower bound on the role of credit in driving house prices.

Q12: What are the implications of allowing savers to frictionlessly trade housing with borrowers?

When savers are allowed to frictionlessly adjust their housing demand (purchasing housing from or selling to borrowers as credit conditions change), the price-rent ratio response is dampened because savers absorb excess borrower demand. After recalibrating σω,L, the combined credit-and-rate experiment explains 54% of the price-rent ratio boom — roughly 25% less than the benchmark 72%. The authors regard this as an extreme lower bound because in practice saver and borrower housing markets are substantially segmented due to indivisibility, location, and quality differences.

Q13: What are the implications for macroprudential policy?

Macroprudential policies that tighten LTV and PTI limits are effective at slowing house price growth in the benchmark economy, where rental market frictions are substantial. In the full boom counterfactual, tightening credit standards reduces the rise in price-rent ratios by 55%. However, in the no-segmentation economy, the same tightening reduces price-rent ratio growth by only 5%, because landlords readily absorb credit-driven demand and pin prices to the present value of rents. The effectiveness of macroprudential policies is therefore deeply dependent on the degree of rental market segmentation.

Q14: Why do the authors prefer the CBRE Torto-Wheaton rent index over typical rent measures?

The TW index uses a repeat-rent methodology on newly-leased multi-unit apartments, which better captures current market conditions than median rent measures, which are biased by composition changes and are sticky due to long-term lease contracts. Since the price-rent ratio is meant to capture the rent a unit could command if leased instead of sold, newly-leased apartment rents are more appropriate for constructing this ratio. The TW index is available for 53 CBSAs from 1989 and 62 CBSAs from 1994.

Q15: Why do the authors estimate the inverse slope rather than the slope directly?

The first stage for the homeownership rate response is very weak — the estimated coefficients are small and imprecise, so using the homeownership rate as an endogenous variable would suffer severe weak instrument problems. Instead, the authors use the price-rent ratio as the endogenous variable (with a much stronger first stage) and the homeownership rate as the outcome, obtaining the inverse slope (homeownership response per unit price-rent ratio response). The upper bounds of the 95% confidence intervals for the inverse slope range from 0.12 to 0.56 across horizons, corresponding to lower bounds on the slope of 1.8 to 8.4.

Key Concepts

Tenure Supply Curve. The menu of price-rent ratios at which landlords are willing to supply varying quantities of owner-occupied housing (i.e., sell rental units to potential homeowners) at a given total housing stock. Defined in price-rent ratio versus homeownership rate space. Distinct from the absolute supply of housing via the construction sector; shifts in the construction margin affect absolute quantities and prices but not necessarily the price-rent ratio or the ownership share. The slope of this curve — not the level — is the central empirical and structural object of the paper.

Market Segmentation (in the paper’s sense). The degree to which credit-insensitive agents (landlords, unconstrained savers) cannot absorb credit-driven demand from constrained borrowers. Perfect segmentation means owner-occupied and rental housing are entirely non-fungible, so all credit-driven demand falls on a fixed supply of owned units. Zero segmentation means landlords (or savers) can frictionlessly convert between owned and rented housing at a price tied to present discounted rents. In this paper, segmentation is measured continuously by the slope of the tenure supply curve.

Sufficient Statistic (for segmentation). The ratio of the causal elasticity of the price-rent ratio to the causal elasticity of the homeownership rate, both with respect to the same identified credit supply shock. This ratio identifies the slope of the tenure supply curve and is sufficient to calibrate a structural model to recover the role of credit in driving house prices for arbitrary combinations of shocks, even when those shocks differ from the identifying variation.

Ownership Benefit Heterogeneity. An additional idiosyncratic utility flow (positive or negative) that borrowers or landlords receive from owning versus renting a given unit, modeled as a logistic distribution. This within-type heterogeneity generates a fractional and time-varying homeownership rate in the model and maps directly into the slope of the demand and tenure supply curves. The dispersion parameter σω,L for landlords governs the slope of the tenure supply curve; higher dispersion implies a steeper (more segmented) supply curve and larger price-rent ratio responses to credit shocks.

Marginal Collateral Value (CB,t). The shadow value to borrowers of the additional credit that can be collateralized by an additional dollar of housing value, equal to µB,t × FLTV × θLTV in the model. A relaxation of credit standards (raising θLTV or θPTI) or a decline in credit costs raises CB,t, increasing borrower reservation prices and shifting the housing demand curve outward. This is the channel through which credit conditions enter house price dynamics.

Local Projection IV (LP-IV). A generalization of Jordà (2005) local projections to instrumental variables settings, as in Ramey (2016) and Ramey and Zubairy (2018), extended to a panel context with CBSA and time fixed effects. Used to estimate impulse responses of price-rent ratios, house prices, and homeownership rates to credit supply shocks at horizons 0 through 5 years, instrumenting for endogenous credit growth using the conforming loan limit shift-share instrument.

Conforming Loan Limit (CLL) Instrument. A shift-share instrument for local credit supply constructed by interacting the share of mortgage originations in the prior year falling within 5% of the current year’s CLL with the percentage change in the national CLL. Cities where a larger fraction of loans cluster near the CLL threshold experience a larger credit supply shock when the CLL increases, because more loans shift from unsubsidized to GSE-subsidized rates. The instrument is constructed using the change in the national CLL only to avoid endogeneity from high-cost area adjustments.