Mortgage Lock-In, Mobility, and Labor Reallocation

The study investigates how the U.S. mortgage system—particularly long-term, fixed-rate mortgages—can inadvertently discourage household mobility, and by extension, hinder labor reallocation. Mortgage holders locked into low interest rates face steep financial penalties if they sell their home and take on a new, higher-rate mortgage. With rates rising dramatically in recent years, this “lock-in” effect could prevent workers from relocating for better job opportunities, thereby reducing efficiency in labor markets. 

The authors develop a theoretical framework that links the difference between a household’s locked-in mortgage rate and prevailing market rates—termed the mortgage rate delta (Δr)—to moving behavior. Households face a choice: stay, refinance, or relocate and remortgage. The model predicts an asymmetric relationship: when Δr is small, moving is discouraged, but once Δr is large enough to make refinancing attractive, mobility becomes less responsive. Empirically, they use individual-level credit records (the GCCP dataset) from 2010 to 2018 and exploit variation in origination timing as an instrument to identify causal effects. This approach controls for borrower and geographic characteristics. 

The empirical findings are compelling: a one percentage-point (1 p.p.) increase in Δr—a larger disparity between a borrower’s locked-in rate and current rates—leads to a 9% reduction in household mobility, with the effect rising to 16% in recent years (2022–2024). The estimated effects are economically meaningful: households had $27,000 or more in present-value mortgage payment increases from a 1 p.p. rate rise, substantially raising the cost of moving. The data also show the asymmetry predicted by theory: when Δr is high, the option to refinance makes moving less sensitive to further changes in Δr. 

Beyond moving rates, mortgage lock-in dampens labor reallocation. Responding to nearby wage growth (within a 50–150 mile radius), borrowers with higher lock-in (i.e., lower Δr) are significantly less likely to move compared to less-locked-in peers. This implies that rising rates not only reduce geographic mobility but also blunt the labor market’s responsiveness to local economic opportunities. The quashing of fluid labor movement could have considerable implications for productivity and job matching in a dynamic economy.

Fonseca and Liu conclude that mortgage lock-in is a potent friction limiting mobility and labor reallocation, especially during periods of monetary tightening. Fixed-rate mortgages—while providing interest-rate insurance—can impede optimal labor allocation when rates rise sharply. These findings carry broader policy implications: features like mortgage portability or loan assumability, common in other countries, might mitigate lock-in effects but are rare in the U.S., excluding some FHA/VA products. Overall, the study highlights how mortgage market design can unintentionally distort labor markets and suggests reform options to improve flexibility and mobility.

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