低利率爲何存在 Reason for low rates is real, monetary and financial

Why are interest rates so low? What are the chances that they will soon rise? These questions matter not just to central bankers and financiers but also to business people, savers and the wider population.

爲何利率如此之低？它們很快上漲的機率有多大？這些問題不僅對央行官員和金融家們重要，而且對商人、儲戶以及一般人也很重要。

Let us start with the facts. The intervention rates of the four most important central banks of the high-income countries — the Federal Reserve, European Central Bank, Bank of Japan and the Bank of England — are all close to zero. These rates have been extremely low since soon after the worst of the global financial crisis, in September and October 2008.

讓我們先來看一些事實。高收入國家最重要的四家央行——美聯儲(Fed)、歐洲央行(ECB)、日本央行(BoJ)和英國央行(BoE)——的干預利率全都接近於零。在2008年9月和10月全球金融危機全面爆發之後不久，這些利率就一直處於極低的水平。

In addition, all these central banks have expanded — or, in the cases of the ECB and the BoJ, are now expanding — their balance sheets, with a view to lowering interest rates on longer-term government bonds.

此外，爲了降低較長期政府債券的利率，這些央行全都擴張了它們的資產負債表——或者就歐洲央行和日本央行而言，仍在擴張資產負債表。

Partly as a result, long-term interest rates on conventional bonds have also fallen to extremely low levels: in mid-September 2015, yields were 0.3 per cent on 10-year Japanese government bonds; 0.7 per cent on the German bonds; 1 per cent on French bonds; 1.8 per cent on Italian and UK bonds; and 2.1 per cent on US bonds.

這在一定程度上也造成常規債券的長期利率也降至極低水平：2015年9月中旬，日本十年期政府債券的收益率爲0.3%；德國債券的收益率爲0.7%，法國債券是1%，意大利和英國債券是1.8%，而美國債券是2.1%。

This is not just a story of low nominal rates. Global real interest rates on safe bonds have averaged only 2 per cent since 2000. Currently, they are not far from zero.

這不僅僅是名義利率偏低的故事。自2000年以來，全球安全債券的實際利率平均僅爲2%。而現在它們已經離零利率不太遠。

Ten-year US Treasury inflation-protected securities (TIPS) yielded 0.6 per cent in late September, while even 30-year TIPS yielded just 1.3 per cent. According to Andy Haldane, the Bank of England’s chief economist, these are the lowest real interest rates for 5,000 years. This is what John Maynard Keynes meant by the “euthanasia of the rentier”. Not surprisingly, rentiers hate it.

美國十年期通貨膨脹保值債券(TIPS)在9月末的收益率爲0.6%，即便是30年期TIPS的收益率也僅爲1.3%。據英國央行首席經濟學家安迪哈德恩(Andy Haldane)稱，這些實際利率是5000年來最低的。這就是約翰蔠納德凱恩斯(John Maynard Keynes)所說的“食利者的安樂死”。並不令人意外的是，食利者憎恨這種低利率。

There are three big-picture explanations of the combination of highly stimulative monetary policies, ultra-low nominal and real interest rates and the absence of inflation. The first is monetary; the second is real; and the third is real, monetary and financial. This last lies at the heart of my book, The Shifts and the Shocks.

至於爲何出現這種高度刺激性的貨幣政策、名義和實際利率超低以及沒有通脹跡象的組合，有三種宏觀的解釋。首先是貨幣因素，其次是實際因素，第三是實際因素加上貨幣和金融因素。最後一點是我在《轉折與衝擊》(The Shifts and the Shocks)一書中闡述的核心觀點。

The first explanation is that of the Bank for International Settlements. As its Annual Report argues: “Rather than just reflecting the current weakness, low rates may in part have contributed to it by fuelling costly financial booms and busts. The result is too much debt, too little growth and excessively low interest rates. In short, low rates beget lower rates.”

第一種解釋是國際清算銀行(Bank for International Settlements)的解釋。該行在其年度報告中辯稱：“低利率並非僅僅反映出當前的疲弱，它可能通過助長代價高昂的金融繁榮和蕭條，在一定程度上加劇了當前的疲弱。結果是過多的債務，增長乏力以及利率水平極低。簡言之，低利率導致了更低的利率。”

The objection to this view is that it rests on the assumption that monetary policy is able to distort long-term interest rates — among the most important of all prices — for decades. It rests, too, on the assumption that pursuing such ultra-easy policies will show up not at all in inflationary pressure, but exclusively in the behaviour of the financial system. This seems wildly implausible.

這種觀點站不住腳的一個理由是，它基於這樣一個假設：貨幣政策能夠持續幾十年一直扭曲長期利率——長期利率處於最重要的價格之列。它還假設：實施此類超級寬鬆政策將完全不會體現在通脹壓力上，而只是體現在金融體系的行爲上。這似乎完全說不通。

At the heart of the second explanation lie shifts in the desire to save and invest. This is the“savings glut” hypothesis of Ben Bernanke, former chairman of the Federal Reserve. Mr Haldane elaborates this hypothesis as “excess savings in the east, deficient investment in the west, worsening demographic trends and rising inequality”.

第二種解釋的核心在於儲蓄和投資意願的轉變。這是美聯儲前主席本伯南克(Ben Bernanke)的“儲蓄過剩”假說。哈德恩將這種假說概括爲“東方儲蓄過剩，西方投資不足，人口結構趨勢日益惡化，不平等程度不斷加劇”。

The difficulty with this analysis is that it gives no explanation for the financial crisis. If one holds to this explanation, one has to argue that the crisis was just the result of foolish deregulation and wild profit-seeking in an irresponsible financial sector. That, too, seems implausible. The question has to be: why did such a huge crisis happen just when it did?

這種分析的問題在於，它沒有對此次金融危機做出解釋。如果有人堅持這種解釋，他不得不辯稱，危機只是愚蠢的放鬆監管以及不負責任的金融行業瘋狂逐利的結果。這似乎也不太可信。人們不得不質問：爲什麼如此巨大的危機偏偏在那個節骨眼上爆發？

The third (and, in my view, correct) explanation is a synthesis of the other two. The simplest form of that synthesis is the Keynesian view: the short-run equilibrium in the economy is determined by the intersection of real and monetary forces. The former determine equilibrium (or natural) interest rates, which the central bank then seeks to deliver.

第三種解釋是其他兩種解釋綜合而成（在我看來，這種解釋是正確的）。最簡單的綜合是凱恩斯的觀點：經濟中的短期均衡由實際因素和貨幣因素共同決定。實際因素決定了均衡（或稱自然）利率，央行隨即尋求提供這樣的利率。

Yet, in seeking to deliver the monetary conditions needed for equilibrium between savings and investment at high levels of activity, the central bank has to encourage credit growth. But that credit growth might be — and in recent decades has been — highly destabilising, because it requires massive leveraging, particularly of property assets, and leads to financial booms and busts.

然而，爲了在高經濟活動水平下提供儲蓄和投資均衡所需的貨幣條件，央行不得不鼓勵信貸增長。但那種信貸增長可能極大地破壞穩定（在最近幾十年就是如此），因爲它需要龐大的槓桿（尤其是對房地產資產），導致金融盛衰。

The correct story, then, is of the interaction between real forces on the one hand, and monetary and financial forces on the other. The savings glut was a causal factor. But its impact came via monetary policy and the financial system, and so via financial booms and busts.

因此，正確的解釋是實際因素與貨幣和金融因素共同作用的結果。儲蓄過剩是一個誘因，但其影響是通過貨幣政策和金融體系傳遞的，進而通過金融盛衰產生衝擊。

So what does this view imply for the future of world interest rates? Here are five implications.

那麼，這種觀點對未來的世界利率意味着什麼？這裏有5個方面的涵義。

First, people feel that savings have to be valuable. On average, they are. But at the margin, they are not. And the price of anything is decided at the margin. In this case, it is zero.

首先，人們覺得，儲蓄必須有價值。一般來說確實如此。但在邊際領域，它們沒有價值。所有物品的價格都由邊際領域決定。在這種情況下，它是零。

Second, the bursting of the credit bubble in the high-income economies led to another huge credit bubble, this time in China.

其次，高收入經濟體的信貸泡沫破裂導致又一個巨大的信貸泡沫，這次是在中國。

Third, after the end of the Chinese bubble, the global savings glut is likely to grow in coming years. China has a national savings rate not far short of 50 per cent of gross domestic product. But its investment rate (which is almost as high) seems sure to fall.

第三，在中國泡沫結束之後，全球儲蓄過剩現象可能在今後幾年加劇。中國國民儲蓄與國內生產總值(GDP)之比接近50%，但其幾乎同樣高的投資比率似乎必然會下降。

Fourth, the debt overhangs created by the western and subsequent Chinese credit booms have been large enough to constrain spending for a long time.

第四，西方以及隨後的中國信貸繁榮遺留了鉅額債務，足以在很長時期內遏制支出。

Finally, for strong global growth, we would seem to need another credit boom somewhere. But where might that happen? The obvious candidate for another such boom would be the US. If so, weak global demand is likely to keep US interest rates very low.

最後，要想實現全球經濟的更強勁增長，我們似乎需要其他地方再來一場信貸繁榮。但是可能在哪裏呢？一個明顯的候選地將是美國。若果真如此，疲弱的全球需求可能讓美國利率保持在極低水平。