Time is money: How landbanking constrains housing supply

Many housing policies aim to increase supply and reduce prices through rezoning, relying on the assumption that increasing allowable densities automatically accelerates the rate of housing supply. However, the existence of landbanking (land hoarding), where land able to be profitably developed for housing is withheld from the market in anticipation of future gains, undermines the logic of such policy changes. We expose major limits of the static housing supply model behind these policies by looking at the degree to which landbanking behaviour is consistent with model predictions. To do this, we assemble a new dataset of home sales and landbanks from the annual reports of Australia’s top eight publicly-listed residential developers from 2001 to 2018 and use complete state-level planning approvals and lot production data in Queensland, Australia. In contrast to the static model prediction that landbanks serve the function of inventories, and are hence minimised, we find that (1) over 200,000 housing lots, or 13 years of new supply, are held by the eight largest housing development companies, and eight years of these landbanks are held in housing subdivisions that are approved and already for sale, that (2) the amount of zoned supply in a region is unrelated to the rate of new housing supply, and that (3) housing developers routinely delay housing production to capitalise on market cycles. Dynamic incentives to maximise total returns, including capital gains in the option value of undeveloped land, could be related to observed behaviour.