Most new borrowing during America’s housing boom was for spending
由于房屋升值所带来的抵押借贷资金,多数被用于消费

HOW big an influence on spending is housing wealth? Hopes for a consumer revival in countries where house prices have slumped rest, in part, on the answer. A purist view is that the value of homes has no “wealth effect” on consumption. An increase in house prices only raises the future cost of shelter. Those about to trade down or sell out receive a windfall, but first-time buyers and those hoping to buy a bigger home are worse off. The overall effect on wealth is a wash. But even if that is correct, house-price increases may still have an impact as they create housing collateral for consumers who could not otherwise borrow. A study* by Atif Mian and Amir Sufi of the University of Chicago’s Booth School of Business pins down the size of this effect, using the credit records of almost 70,000 American borrowers.

房产价格对于消费支出的影响有多大?人们对于这个国家消费复苏的期待在一定程度上就寄希望于这个问题的答案,虽然房价已经遭受重创.一种最纯粹的观点认为,房产价值对于消费已经失去了”财富效应”.房价的升高只是提高了未来居住的成本.那些投资于房产的人们借此发了一笔横财,而初次购房者以及二次换购者的”大房子梦想”却打了水漂.总的来说,”财富效应”微乎其微.但即使那个观点是正确的,房价的提升依然有一定的作用,那就是对于那些之前无力贷款的人来说,房价的提升可以为他们进行更高额度的贷款担保.由芝加哥大学布斯商学院的Atif Mian 和Amir Sufi研究衡量了财富效应的程度,那是通过70000名美国借款者的信用记录得出的结论.

It could be that an unseen influence, such as greater optimism about future earnings, pushed up both house prices and debt. So the authors use their granular data to first establish a link between the two, which is apparent in the aggregate figures up to 2006 (see chart). They found that house prices and household debt increased most where the supply of new housing was limited—in places that are hemmed in by hills, rivers or the ocean. But in cities where housing supply is very “elastic”—where homes can easily be built to meet demand and prices did not rise—debt barely rose either. This suggests that house-price rises led to more borrowing.

这会是一种无形的影响,就像对于未来收入的乐观情绪一样,既推高了房价,也提升了负债程度.所以研究者利用散点图首先建立了这两个因素之间的线性关系,范围是2006年之前的所有数据.他们发现房价和家庭负债在新屋供应量有限的地区增加最快-那些被山岗,河流或者大洋所包围的地区.而在城市里,房屋的供应却非常有弹性–新房子可以很容易得被建造以满足需求,并且房价并不升高,同时负债也并不升高.这显示出是房价的上升导致了更多的借债.

How much of this was simply down to new buyers needing bigger home loans? By limiting their sample to those who were already homeowners in 1997, before the boom in housing and credit, the authors were able to measure how much of the rise in debt was the result of cashing in on higher home values. They reckon almost 60% of increased debt between 2002 and 2006 came from this source. Put another way, every $1 increase in home values led to a rise of 25-30 cents in borrowing. That is far bigger than some long-standing estimates of the wealth effect from rising asset values, which are in the 3-5 cent range (though these include the response of renters, too).

这一现象如何解释新屋购买者需要更多的房屋抵押贷款呢?通过将研究对象的范围限制到那些1997年就已经买了房子的人,在房价和信贷大幅发展之前,研究者可以测算出债务的增长和房价涨幅之间的定量关系.他们估计在2002年到2006年中,债务增长的60%来源于房屋增值.从另一个角度来说,房价每上升1美元,负债就增加大约25-30美分.这远比之前很长时间以来估计的3%-5%超出许多(虽然这也都包括了借款人的利息)

Money released from housing equity was not funnelled into other forms of saving. Homeowners in cities where house prices rose quickly were less, rather than more, likely to invest in other properties. Funds raised against rising home equity were not used to pay down other debts. And fewer households invested in financial assets, such as shares and bonds, when house prices were rising. All this suggests that almost all of the $1.45 trillion the authors estimate was borrowed against rising home equity was used for spending.

由房产价值提升所带来的财富并未转化为其他形式的积蓄.在房价上涨更快的城市,房屋所有者更少得投资于其他资产,而不是更多.由于房产升值所增加的储蓄并未用来支付其他债务.而且在房价上升时很少有人投资于金融资产,比如股票和债券.这些都指向一个结果,根据研究者估计,由房产升值所带来的大约1450亿美元被用于消费.

Digging deeper into their data, the two Chicago economists discovered that the pattern of home-equity withdrawal was far from uniform. The young were keener to cash out than the old. That is at odds with the life-cycle theory of consumption, which says that the young amass wealth so that they can spend it in old age. Borrowing by the top quartile of homeowners ranked by their creditworthiness scarcely rose in response to rising house prices. That is evidence against a pure wealth effect, says Mr Sufi. The most eager borrowers were those with the lowest credit ratings and whose credit-card borrowing was closest to the agreed limit. That sits well with a model of willing but frustrated consumers given access to credit through the rising value of their homes.

通过更深一步的数据分析,这两位芝加哥的经济学家发现将房产升值变现的渠道也大不相同.相比于老年人,年轻人更倾向于持有现金.这反倒和生命周期消费理论相矛盾,那种理论认为年轻人会积蓄大量的财富以供晚年享用.一个仅依靠信誉进行排名的借款人榜单中,前四分之一的借款人因为房产价值的提升而增加了债务.Mr Sufi认为这是一个能够体现财富效应的证据.而那些最渴望借款的人一般是那些信用等级较低或者借款额已经接近限额的那些客户.这和那个模型非常契合,那就是通过房产升值从而能够提升信用等级的客户可以满足先前强烈但是受压抑的消费欲望.

It also fits a more worrying interpretation: that many of the keenest borrowers were myopic or had problems with self-control. More than a third of new defaults in 2006-08 were because of home-equity-based borrowing. Default rates for low credit-quality homeowners rose by more than 12 percentage points in places where housing was scarcest and prices had risen most. In “elastic” cities, by contrast, the increase was less than four percentage points. This suggests huge over-borrowing. Prospects for a sustained recovery look dim if households that are most inclined to spend are mired in negative equity.

这也符合一个令人忧虑的解释:那些最渴望借款的人通常很短视或者缺乏自控力.在06-08年间,有三分之一的还款拖欠是由于房屋抵押贷款.在那些房屋稀缺,房价大幅上涨的地区,低信用等级的客户违约率已经上升了超过12%.而在市场充满弹性的城市中恰恰相反,只上升了不到4个百分点.这显示出了大量的过度借贷.如果那些负资产的家庭还是倾向于消费的话,那么持续性经济复苏的前景依然是一片黯淡.