中文摘要：

2004年以来，中国大中城市房价加速上涨，逐渐形成难以调控的“坚硬泡沫”。本文研究发现：地方政府对城市土地市场的垄断正是泡沫的主要“硬核”之一。随着各市县土地收购储备机构的普遍成立以及“招拍挂”土地出让方式的强力推行，原来实际为多头、分散供给的城市土地市场逐渐转变为地方政府控制下的垄断性市场。理论模型表明：如果地方政府以土地收益最大化为决策目标，则其理性选择就是通过控制土地供给量推高城市土地价格，而经过房地产开发企业的竞争，高地价将最终传导形成高房价。通过投资者的“预期成本效应”，由竞价市场产生的高地价信号将立即拉高当期房价。实证研究支持上述理论假说。这意味着要抑制房价的过快上涨，长期治本之策在于打破城市土地市场的垄断格局，中短期来看，需要激励地方政府改变其以土地收益最大化为主要决策目标的做法。

英文摘要：

Since 2004, the house price has been accelerating the rising speed in the large and medium - sized cities of China. As a result, the hard bubble gradually appears which is immune to various macroeconomic policies. This paper finds that one of the hard cores in this bubble is the monopoly power of local government in the city land market. With the establishment of land banks in cities and the compulsory implement of ＇ tender, auction and listing＇ method of land grant, the former competitive city land market was gradually substituted by the monopoly market controlled by local government. Theoretical analysis demonstrates that local government＇s rational selection is to push up land price by decreasing the land supply if its object is to maximize the land profit. By the competition of real estate developers, the higher house price will be formed on the basis of higher land price. Furthermore, through the investor expectations on land cost of house, the high land price signal will lead to one high house price. Empirical study supports above hypothesis. According to our research, in order to slow down the rising speed of house price, the fundamental policy is to change the monopoly land market into a competitive market. In the short run, local government should be motivated to change its objective of land profit maximization.