美国经济二次探底预测靠不住

    本周股市大幅跳水，华尔街的经济学家们争先恐后地重新调整经济再度陷入衰退的预测。短短几天之内，一个共识浮出水面：大多数的分析师认为经济二次探底的可能性在30%-40%之间。

    高盛（Goldman Sachs）首席经济学家最近表示在接下来的9个月经济再次陷入衰退的可能性达到三分之一。标普（Standard & Poor's）的经济学家（这些经济学家独立于评级部门）以及美银美林（Bank of America Merrill Lynch）的经济学家们都将可能性提高到了35%。德意志银行（Deutsche Bank）则定得更高，他们的预测值敲定为40%。

    资产管理巨头贝莱德（BlackRock）的首席证劵策略师鲍勃•多尔上周三表示，该公司认为经济再次出现衰退的可能性为30%。他写道，“我们预计经济不会出现强劲的增长周期，但也不会出现再度衰退。”

    考虑到现在市场的狂热，这样的预测虽然远谈不上乐观，但还是令人宽慰的：这些策略分析师都认为经济不太可能出现二次探底。诸位高人纷纷发表预测自己，我们最好别忘了，上一次经济衰退时，他们的预测就落空过。

    根据美国国家经济研究局（National Bureau of Economic Research）的记录，上次经济衰退从2007年12月正式开始。2008年1月，彭博社（Bloomberg）调查的经济学家认为经济衰退的可能性为40%。同年2月，经济学家们将可能性提高到了50%，此后一直维持在该水平【4月在投资银行与证券交易公司贝尔斯登（Bear Stearns）倒闭时出现过短暂上升】。9月初，就在雷曼兄弟（Lehman Brothers）倒闭和股市开始暴跌的前几天，经济学家仍然将经济衰退的可能性定为51%。

    随大流

    这些几率的惊人之处在于它们变化的频率之快。当年10月，经济学家宣称经济衰退即将到来的几率高达90%（当时除了穴居原始人，应该没人不知道经济将陷入衰退了吧。）

    最近一次预测调整也同样极其突然。今年6月，预测者认为出现衰退的可能性只有15%；到7月，可能性降至13.8%。随着越来越多的经济学家（不可思议的类似）给出30%-40%的预测范围，8月份的调查数据将会有显著提高。

    2008年和眼下的情形类似，经济学家修正预测的方式都是应激式的。两者都发生在股市强烈震荡之后。每一次市场都让分析人士出乎意料，分析师随后再根据市场下滑调整预期。

    这是不是意味着市场在左右分析师的预测？不是狗摇尾巴，而是尾巴摇狗？这些调整本身是合情合理的，因为市场崩盘会摧毁上万亿美元的公司及个人财富，放大可能诱发衰退的因素。

    赖斯大学（Rice University）商学院教授古斯塔沃•古隆说：“许多衰退共有的问题是它们都是由意料之外的事件引发的”。古隆指出70年代的石油危机和08年的金融危机出乎许多预测者的意料。他说：“经济学家失手是因为这类事件大都难以预测。”

    但是分析师在股市大跌之后做出调整的幅度和速度让预测这项行为本身变得十分可疑。经济学家对市场反应强烈，不过多尔指出，自大萧条以来，跌幅达15%或以上的股市下跌共计有30次，但只有两次股灾引起了衰退。

    事实上，导致近期股市暴跌的事件有很多，包括美国债务评级遭到下调，华盛顿的债务上限谈判僵局以及欧洲的主权债务危机，这些都已经持续了数月。经济指标也令人担忧。今年夏季美国的招聘和消费支出指数双双下跌。制造业活动也同样衰弱。国内生产总值（GDP）增长虽不是负数——一般认为连续两个季度GDP负增长则意味着经济衰退——但也只有低得可怜的1.3%。

    与此同时，债券投资者大量买入美国国债，远离风险高的投机性债券。法国巴黎投资（BNP Paribas Investment Partners）全球信贷分析师马丁•福里得森认为，垃圾债券利差现在显示经济陷入衰退的几率为48%。福里得森补充表示，现在的利差表明高收益的债券跌幅过大。

    绝大多数预测者仍然认为二次衰退不太可能。贝莱德的多尔写道，首次申请失业金人数不断减少时出现经济衰退的情况十分罕见。他将现在的情况与08年做了比较，当时连黄金的价格都在下跌，这说明当时存在债务通缩问题。他说，现在金价上涨说明投资者期待着新的经济刺激方案。多尔建议投资者把现金投到市场中去。

    有些经济学家对此持有不同意见。格鲁斯基-谢菲资产管理公司（Gluskin Sheff）的大卫•罗森博格就是其中之一。这位资深市场分析家在2008年1月曾指出经济已经处于衰退。他最近的言论嘲笑了所谓的共识。他撰文说，“怀孕还是没怀孕，这是非此即彼的事，是否陷入经济衰退也是如此。”

    罗森博格在6月接受《财富》杂志（Fortune）访问时还说“债券市场也显示衰退即将来临”，他认为出现二次探底的可能性为99%。他说：“华尔街不要再说35%的可能性这种废话了。”

    As stocks took a blistering dive this week, Wall Street economists scrambled to readjust their forecasts of the likelihood that the economy is headed for another recession. In a matter of days, a consensus quickly emerged: Most strategists now place the odds of a double dip at 30-40%.

    Goldman Sachs' (GS) chief economist recently announced that there was a one-in-three chance that there will be another recession in the next nine months. The economists at both Standard & Poor's (who work separately from the ratings division) and Bank of America Merrill Lynch (BAC) moved their recession meters to 35%. Deutsche Bank (DB) aimed a little higher, placing its estimate at 40%.

    Bob Doll, the chief equities strategist at BlackRock (BLK), announced Wednesday that the asset management giant sees a 30% chance of a recession. "We don't anticipate a vigorous economic cycle, but we are not arguing for recession either," he wrote.

    Given the current mania in the markets, such prognostications, while far from cheery, are still comforting: The strategists agree that the economy probably won't double dip. But as the oddsmakers weigh in, it's important to remember that they didn't exactly hit the ball out of the park the last time around.

    The last recession officially started in December of 2007, according to the National Bureau of Economic Research. In January of 2008, economists surveyed by Bloomberg put the likelihood of a recession at 40%. That February, they lifted the odds to 50%--and then left them there for months (there was a brief spike in April, after Bear Stearns went under). In early September, just days before Lehman Brothers collapsed and the stock market imploded, economists still placed the probability of a recession at just 51%.

    Reacting with the pack

    What's incredible about those odds is the speed at which they changed. That October, economists declared a 90% chance that a recession was coming (by then, you'd have to be a cave-dweller to think otherwise).

    The latest revisions are similarly drastic. This June, forecasters saw a mere 15% chance of a recession; in July, that number actually dipped to 13.8%. As more and more economists roll out their (uncannily similar) estimates in the 30-40% range, it seems likely that August's survey will show a marked increase.

    In both 2008 and today, economists modified their estimates in a reactionary fashion: Both revisions occurred after the stock market had already tanked. In each case, the market caught strategists by surprise, and strategists adjusted their forecasts in response to the dips.

    Does that mean the tail, i.e. the market, is wagging the dog? The revisions themselves are justified; market crashes, which can destroy trillions of dollars in corporate and personal wealth, can amplify recessionary factors.

    "One of the problems with many recessions is that they're triggered by unexpected events," says Gustavo Grullon, a professor at Rice University's school of business. Grullon points out that the oil crisis in the 1970's and the financial crisis in 2008 caught many forecasters by surprise. "Economists are having trouble because most of those events are really unpredictable," he says.

    But the magnitude -- and velocity -- at which strategists adjust their estimates after stocks crash renders the practice of oddsmaking suspect. Economists react strongly to the market -- but Doll pointed out that there have been 30 market declines of 15% or more since the Great Depression, and that only two led to recessions.

    Indeed, many of the events that precipitated the latest crash -- the downgrading of U.S. debt, the political gridlock in Washington, and the European sovereign debt crisis -- have been unfolding for months. Economic indicators have also been dreadful. Hiring and consumer spending both took a dip this summer. So did manufacturing activity. GDP growth hasn't turned negative -- the rule of thumb is that two quarters of negative growth signify a recession -- but the economy grew last quarter at a paltry 1.3%.

    Bond investors, meanwhile, have piled into Treasuries and fled speculative debt. Junk bond spreads now signal a 48% chance of a recession, according to Martin Fridson, global credit strategist at BNP Paribas Investment Partners. Fridson went on to add that the spread meant that high yield bonds had probably fallen too much.

    Most forecasters still maintain that a second recession is unlikely. BlackRock's Doll wrote that it would be rare for a recession to begin while initial unemployment claims were declining. He contrasted the current environment with the situation in 2008, when even the price of gold was declining, signifying a "deflationary debt problem." The rise in gold prices today, he said, indicates that investors expect another stimulus. Doll advised investors to put their cash to work in the market.

    Not all economists agree. One strategist who has veered from the pack is Gluskin Sheff's David Rosenberg, the market Cassandra who said in January of 2008 that the economy was already in a recession. In a recent note, Rosenberg mocked the new consensus. "You cannot be sort of pregnant any more than you can maybe, perhaps, be in a recessionary state," he wrote.

    "The bond market also clearly has recession in its sights," added Rosenberg, who told Fortune in June that there was a 99% chance of a double dip. "None of this namby pamby '35% odds' stuff out of Wall Street."