欧洲和日本的利率为负，这种情况在美联储采取进一步加息行动之前会维持一段时间。因此，如果经济再度陷入低迷，各国央行调整利率水平、放宽货币政策的余地就很小了。
一种方法是“直升机撒钱”，即央行增印钞票来刺激经济，或是直接补偿给消费者或是资助公共事业。这个方法旨在刺激需求并增加通胀，因为很多国家当前的通胀率都低于预期水平。金融时报的 Martin Wolf 近日对这一观点表示了赞同。对冲基金经理 Ray Dalio 也认为“直升机撒钱”是个好办法。
这个方法为什么有效呢？经济学家 Simon Wren-Lewis 指出：“将印刷的钞票补偿给消费要比购买政府债券 (QE) 好得多。因为消费者会把钱花掉，而政府债券会降低长期利率来刺激经济。第二种方法已经尝试过了，而且不太成功。所以为什么不试试第一种方法呢？”
但这种方法若想实施需要经过政府的严格审批，而且会导致非常现实的问题，所以无论是德国政府还是美国国会都很难批准。但“直升机撒钱”更吸引左翼政客们，因为这是一种再分配性政策，或是使所有人受益，或是投资到基础设施中，降低失业率。
那么市场会如何反应？花旗集团 Steven Englander 试图从一份调查报告中得出结论。他将美国假象为一架直升机，结果显示，收益曲线会变陡峭（长期债券收益会增加），证券表现会改善（尤其是依赖于经济增长的周期性股票）。出人意料的是，他认为美元的表现会变好，强势增长的美元和高收益的债券会吸引国外资本。
最终效果如何很大程度上取决于刺激的大小和方法。适当的刺激会使通胀和需求略有提升，而不会导致魏玛式恶性通胀。这种增长是永久性的吗？还是说政府会在未来几年内取消这项政策之前先行通知？虽然能够安抚市场情绪，但是某些消费者会开始省钱、减少支出，这将降低刺激的成效。还有一种可能性是大量资金被投入进口产业中，如：平板电视和外国节日等。这会导致经常项目赤字增加，对货币产生潜在的消极影响。此举可能会刺激国外经济，允许他们自由乘坐这架直升飞机。所以多国同时采用“直升机撒钱”是一个好办法，就像雷曼倒闭之后的财政刺激一样。
当然，潜在的阻碍也有不少。如果债券价格下跌，那些购买了超低收益债券的投资者会怎样？养老基金倒是没问题，因为负债会随之减少，但是银行的问题就大了。投资者很可能受到惊吓，政府支出货币化的禁忌也会被打破。如果选民喜欢的无效投资都能由央行来买单，那政府煞费苦心地增加税收、削减支出又是为了什么呢？
这个问题比支持者们想象的要困难得多。金融市场的 Matthew Klein 认为：“央行直接向家庭账户转账的方法简单易行，这样一来，如何处理新造钱币的问题就无需任何政治辩论了。”
但是约有1000万美国家庭和150万英国家庭没有银行账户，他们中大多数人的生活都很贫苦。除此之外，你还要排除一些人吗？罪犯？移民者？你可以想象，这会引起轩然大波的。如果某些人用这笔额外的收入吸食可卡因或是饮酒狂欢，一定会上新闻头条的。用这笔钱建造学校和医院可能更稳妥些。
What if the helicopters took off?
INTEREST rates are negative in much of Europe and Japan, and it may be a while before the Federal Reserve follows up December's quarter-point increase in rates. So that doesn't leave the authorities with a lot of room, in terms of altering the level of rates, to ease policy if another downturn hits.
One option would be "helicopter money" - the central bank could create the money to fund a fiscal stimulus, either by direct transfers to consumers* or by funding public projects such as infrastructure. The idea would be to stimulate demand and potentially increase inflation, which is below target in many countries. Martin Wolf of the FT recently praised the idea, and he hobnobs with the world's policymakers on a regular basis. The hedge fund manager Ray Dalio is another who thinks that helicopter money is the next option.
Why might this be helpful? The economist Simon Wren-Lewis has said there is
an understandable view that it would be better to print money and give it to consumers who would spend it (helicopter money), rather than using it to buy government debt (QE) which may reduce long term interest rates which may help stimulate the economy. The second route has been tried and has not been that successful, so why not try the first route?
It is hard to see any central bank doing this without very explicit approval from their government, and that creates the very practical problem that neither the German government nor the Republicans in the US Congress would ever agree to such a thing. Helicopter money has more appeal to leftwing politicians since it can be classed as a redistributive policy. Either all citizens would get the same payout or, if the money is spent on infrastructure, unemployment would fall.
So how would the markets react? Steven Englander of Citigroup tries to look through the implications in a research note. He works on the assumption of a US helicopter drop (although Europe or Japan look more likely candidates). The yield curve would steepen (long-dated bond yields would rise), and equities would do well (particularly cyclical stocks on the grounds that the effect would be to stimulate the economy. Surprisingly, perhaps, he thinks the effect would be positive for the dollar; stronger growth and higher bond yields would suck in foreign capital.
A lot would surely depend on the size of the stimulus and how it would be framed. A modest stimulus might lift inflation and demand a bit, without leading to talk of Weimar-style hyperinflation. Would the expansion be permanent or would the government pre-announce a plan to "claw it back" in a few years' time? That might reassure the markets but some consumers might save the money to meet the tax bill, making the stimulus less effective. There is also a risk that a lot of money might be spent on imports - flat screen TVs and foreign holidays. That might cause the current account deficit to soar, potentially negative for the currency. The effect might be to stimulate overseas economies, allowing them to free ride on the helicopter. So one answer would be to get lots of countries to pursue helicopter money simultaneously, rather as they agreed to use fiscal stimulus after Lehman collapsed.
There are, of course, lots of potential snags. What would happen to those investors who bought bonds at ultra-low yields if bond prices plunged? No problem for pension funds (whose liabilities would fall too) but it might be a problem for banks. And it is possible that investors might take fright; that monetisation of government spending might be a broken taboo too far. After all, what government would ever want to raise taxes or cut spending, if lots of voter-friendly boondoggles could be financed by a tame central bank?
* This might be more difficult than proponents assume. Matthew Klein at the FT suggests: direct deposits into household accounts offered at the central bank. It’s simple and doesn’t require any political debate about how best to spend the newly created money.
But around 10m US households and 1.5m British adults lack a bank account, many of whom will be poor. Is it fair to exclude them? By the same token, these people may not be on the electoral roll. And would you deliberately exclude people? Prisoners? Immigrants? One can only imagine the political furore that could be created, or the headlines if some people spend the proceeds on cocaine or a drinking binge. Building lots of schools and hospitals might be the safer option.
本文翻译由兄弟财经提供
文章来源：http://www.economist.com/blogs/buttonwood/2016/03/monetary-policy-and-markets