摘要：Mortgage credit expansion policies - such as UK's Help to Buy (HtB) - aim to increase access to and affordability of owner-occupied housing and are widespread around the world. We take advantage of spatial discontinuities in the HtB equity loan scheme, introduced in 2013, to explore the causal economic impacts and the effectiveness of this type of policies. Employing a Difference-in-Discontinuities design, we find that HtB increased house prices by more than the expected present value of the implied interest rate subsidy and had no discernible effect on construction volumes in the Greater London Authority (GLA), where housing supply is subject to severe long-run constraints and housing is already extremely unaffordable. HtB did increase construction numbers without affecting prices near the English/Welsh border, an area with less binding supply constraints and comparably affordable housing. HtB also led to bunching of newly built units below the price threshold, building of smaller new units and an improvement in the financial performance of developers. We conclude that credit expansion policies such as HtB may be ineffective in tightly supply constrained and already unaffordable areas.
关键词：help to buy;house prices;construction;housing supply;land use regulation
