It wasn′t us.doc

2010.03.20 It wasnt us 不是我们的错Mar 18th 2010 From The Economist print editionAlan Greenspan and Ben Bernanke still do not believe monetary policy bears any blame for the crisis造危机货币政策难脱干系，美联储老少掌门不以为然THE desire to rescue a damaged reputation is a powerful motivator. That is one conclusion to draw from a new 48-page paper written for the Brookings Institution by Alan Greenspan, the 83-year-old former chairman of Americas Federal Reserve. A man once hailed as the worlds outstanding central banker is now routinely blamed for the asset bubble and subsequent collapse. This is Mr Greenspans attempt to set the record straight.挽救破损声誉的渴望是个强大的激励因素；从艾伦格林斯潘（Alan Greenspan）最近为布鲁金斯学院（Brookings Institution）撰写的长达48页的论文中便可以看出这一点1。这位83岁高龄的美联储前主席，一度作为万众瞩目的央行行长而备受赞誉的人，如今却因资产泡沫及随后的金融灾难而饱受指责。这篇论文算是格林斯潘为其正名而做的一个尝试。The crisis, he argues, stemmed from a “classic euphoric bubble” whose roots lay in the sharp global decline in nominal and real long-term interest rates in the early part of the 2000s, which fuelled an unsustainable boom in house prices. Thanks to this euphoria, banks misread the risks embedded in complex new financial instruments. Mr Greenspan reckons the best remedy is to improve the systems capacity to absorb losses by raising banks capital and liquidity ratios and increasing collateral requirements for traded financial products.根据他的看法，此次危机源自一个“典型的乐观泡沫”，而后者的根源在于本世纪早期名义与实际的长期利率在全球范围内的急剧下降正是它们助长了楼市难以持久的繁荣。同样由于此类乐观情绪，银行错估了那些与复杂的新生金融品牢牢相关的风险。格林斯潘认为，最佳的疗法在于改善系统承受损失的能力。要做到这一点，需要增加银行的资本与流动性比率，并提高对交易类金融产品的抵押要求。So far, so uncontroversial. Mr Greenspans analysis of the fragilities within finance, and his specific proposals, echo todays policy consensus. The one area where he differs from the reform consensus is over the wisdom of a “systemic regulator”. Todays policymakers see such a regulator, which would monitor the health of the financial system and sniff out incipient problems, as an important improvement. Mr Greenspan says it is impossible to anticipate crises and regards such a regulator as “ill-advised”. 至此，无甚可争。格林斯潘对金融内部脆弱性的分析，以及他的明确建议，均与当下的政策共识相呼应。其不同于改革共识的一点涉及到所谓“系统监管者”（“systemic regulator”）的判断力。此类监管机构将监测金融系统的健康状况，并于早期发现病症所在。对今天的决策者而言，这是个重要的改进。不过格林斯潘认为预言危机乃人所不能，此类监管在他看来并不明智。But the biggest gap between Mr Greenspan and conventional wisdom lies in the role of monetary policy in causing the crisis. In Mr Greenspans telling, central banks were innocent and impotent bystanders in a global macroeconomic shift. Thanks to the end of the cold war and reform in China, he argues, hundreds of millions of workers were absorbed into the global economy. As GDP growth in emerging economies soared, their consumption could not keep up with rapidly rising income, and saving rose. The rise in desired global saving relative to desired investment caused a global decline in long-term rates, which became delinked from the short-term rates that central bankers control.然而，货币政策在这场危机中所扮演的角色，才是格林斯潘与普遍共识的最大分歧所在。按照他的说法，中央银行是无辜的；面对全球宏观经济的转变，他们只是无能为力的旁观者。他认为，由于冷战结束与中国的改革开放，数以亿计的劳动力融入了全球经济。随着新兴经济体GDP的迅猛增长，他们的消费无法与收入的快速增长保持同步，结果增加了储蓄。全球意愿储蓄相对于意愿投资的上升导致了世界范围内长期利率的下降，并使其脱钩于央行控制的短期利率。This explanation is broadly similar to the idea of a “global saving glut” which Ben Bernanke, the Feds current chairman, has long espoused. The similarities between the two mens defence of their monetary records do not end there. The most combative section in Mr Greenspans paperarguing that monetary policy in the early 2000s was not a cause of the housing bubbleis strikingly similar to a speech given by Mr Bernanke at the American Economics Associations annual meeting in January.这一解释与美联储现任主席本伯南克（Ben Bernanke）长期所宣扬的“全球储蓄过剩”（global saving glut）大体相仿2。而二者为其货币决策辩护上的相似性，并未到此而结束。格氏文章中最“滋事儿”的一个章节坚称本世纪早期的货币政策并非楼市泡沫的诱因，这与伯南克今年1月于美国经济学年会上的演说惊人的相似3。Both men make three broad points. First, they deny that monetary policy in the early 2000s was excessively loose by traditional central-bank rules of thumb. That is a criticism frequently made by John Taylor of Stanford University, author of the Taylor rule on how interest rates should change in response to movements in inflation and GDP. Mr Bernanke points out that based on contemporary forecasts for its preferred inflation measure, the Fed actually followed the Taylor rule reasonably closely.三大要点概括这两位的共同主张。首先，他们否认本世纪初的货币政策就传统的央行经验而言是过度宽松的。泰勒法则的创始人、斯坦福大学的约翰泰勒（John Taylor）曾不断就彼时的政策有所批评。该法则规定利率应如何随着通胀与GDP的变化而进行调整。伯南克先生指出，基于对其首选通胀量4的同期预测，联储的政策事实上紧随泰勒法则。Second, both men say there is no evidence that low short-term rates drove house prices upward. Mr Greenspan argues that the statistical relationship between house prices and long-term rates is much stronger than with the Feds policy rates, and that during the early 2000s the traditionally high correlation between policy rates and long-term rates fell apart. Mr Bernanke points to structural models which show that only a modest part of the house-price boom can be pinned on monetary policy.其次，两人均称没有证据表明，是低水平的短期利率推高了房屋价格。格林斯潘认为，房价与长期利率的统计关联要比其与联储政策利率的关联强很多，而政策利率与长期利率传统上的高相关性已于本世纪初出现瓦解。 伯南克先生则指向某些结构性模型，它们显示房价高企只有很小的一部分可以归咎于货币政策。Both are equally sceptical that the increase in adjustable-rate mortgages made short-term rates a more potent driver of house prices. Mr Greenspan says that the pace of adjustable-rate mortgage originations peaked two years before house prices, suggesting they were not driving the bubble. Mr Bernanke argues that the monthly payments on adjustable-rate mortgages were, on average, only 16% lower than those for fixed-rate mortgagestoo small a gap to suggest that short-term rates propelled the boom.对浮动利率按揭的上升致使短期利率成为更强力的楼价推手，两人同样心存质疑。格林斯潘先生说，浮动利率按揭的启动速度早在楼价触顶两年起便达到顶峰，意味者它们与泡沫无关。伯南克的理由则在于，浮动利率按揭的月供额，平均只比固定利率按揭低16%这差距实在太小，难以表明是短期利率助长了这场繁荣。Third, Messrs Bernanke and Greenspan point to the global nature of the house-price boom as proof that monetary policy was not to blame. Both cite new research from economists at the Fed showing that the looseness of monetary policy in different countries was not correlated with changes in house prices.第三，两位先生以楼市繁荣的全球特质，作为货币政策无辜的证据。二者均援引了联储经济学家的新研究，其结果显示，各国宽松的货币政策与房价变化之间并无关联。There is something odd about central bankers denying any responsibility at all for long-term rates, which are, in principle, based partly on an assessment of a stream of short-term rates. Nor is it clear that low short-term rates were as irrelevant as Messrs Bernanke and Greenspan suggest. Jeremy Stein of Harvard University, a discussant of Mr Greenspans Brookings paper, points out that low policy rates may have mattered a great deal for income-constrained borrowers. He points out that adjustable-rate mortgages were used much more in expensive cities, a trend that became more pronounced as the fund rates fell.中央银行家拒绝为长期利率承担任何责任，不免有些蹊跷毕竟在原则上，长期利率部分地取决于对短期利率流向的判断。此外，短期利率是否真的像这两位所宣称的那样无关紧要也不甚清楚。哈佛大学的杰里米斯坦（Jeremy Stein）格林斯潘此篇论文的讨论者之一指出，低水平的央行利率对低收入的借款人而言可能关系重大。他指出在昂贵都市，浮动利率按揭应用得更加广泛，这一趋势则随着联储基金利率的下降而变得更加明显。By looking only at the effect of monetary policy on house prices, Messrs Bernanke and Greenspan also take too narrow a view of the potential effect of low policy rates. Several economists have argued convincingly, for instance, that low policy rates fuelled broader leverage growth in securitised markets.单就货币政策对房价的影响而言，伯南克与格林斯潘两位对低水平政策利率的潜在影响的看法也过分狭隘。比如，一些经济学家已有令人信服的论证：即低水平的央行利率在证券化市场上推动了杠杆率的广泛