非常規時代的中央銀行：貨幣政策獨立性支持全球經濟

作者：約翰·雅尼斯·穆爾穆拉斯 翻譯：人民大學助理研究員廖藝棋 審校：趙戈翰

關於中央銀行獨立性的研究可以追溯到理性預期革命。理性預期理論的前提是人們做選擇時總是基於理性的思考、過往的經驗和可得的信息。理性預期打破了長久以來的理論困境，緩解了20世紀70年代高通脹率、高失業率和低增長率并行的滯脹局面。

在理性預期框架下運行相機抉擇的貨幣政策，私人部門和政府之間的交互行為會導致通脹偏差，並不會帶來任何持續性的產出。產出跟不上，政府不滿意，偏差會進一步增大。在這種預期下，政府和央行制定貨幣政策時，就明確表示要降低通脹，把通脹預期也降到同等低位。

后危機時代的貨幣政策

2008年金融危機和隨之而來的歐債危機改變了獨立央行的運行機制。央行開始接受新的宏觀審慎任務，比如，歐洲央行2014年後就加強了對單一經濟體和單一貨幣體系統性風險的防控。

后危機時代的另一個變化是，穩定價格主要靠預防緊縮，而非遏制過度通脹。因此，所有的主要中央銀行近年來都使用了非常規的貨幣政策工具，包括為銀行提供緊急流動性和信貸支持，放鬆中短期貸款所需的「合格抵押品」的定義要求。

為了將通脹提高到目標水平，多家央行實施了負利率和量化寬鬆，大幅擴張其資產負債表。2008年以來，美聯儲資產負債表規模翻了一番，英格蘭銀行資產負債規模則增長到三倍。歐洲央行自2015年實行量化寬鬆以來，資產負債表規模也擴大了66%。

央行獨立性受到質疑

2008年經濟危機和之後的低通脹引發了對央行獨立性的質疑。首先，外界質疑央行貨幣政策工具的獨立性。其次，即便央行的政策制定並沒有受到其他機構的干擾，但由於局勢的變化，其政策未必能達到預想的效果。筆者認為，此類質疑完全沒有立足點，問題並不來自獨立性本身，而是當下極度寬鬆的貨幣政策與緊縮的財政政策并行的矛盾。

貨幣政策與財政政策、結構政策以及金融政策是本質相連的。制定相關政策的機構或許形式上是各自獨立的，但實質上是互相影響的。而風險就在這裡，如果某個獨立的機構沒能採取適當的措施達到設定的目標，另一個機構就可能對持續的衝擊採取過度的應對措施以達到自己的既定目標。這種情況可能導致其他政策對貨幣政策的「弱主導作用」，破壞了獨立央行意欲建立的以貨幣政策為主導的體制。

當利率長期為負時，貨幣政策的再分配效應就會更顯著，貨幣政策的成效是方達標，也顯得更為重要。這就引起更多針對央行獨立性進行審查的呼聲。人們擔心，當制定貨幣政策的機構被要求達到更多硬性目標時，它還能否在民主的政治經濟體制中保持透明化運行，人們還能否對其決策進行適度的問責？

一家獨立的央行會受到各方制衡並須對民眾負責，因此便需要民意支持。如果負利率持續下去，央行無疑會不得民心，失掉大部分的民意支持。

獨立央行的首要任務還應在於穩定價格，為結構性調整、適當的財政政策和宏觀審慎穩定創造政策空間，如此，才有可能達到恢復增長並創造就業的最終目標——所有的理論和實證也都指明，這是唯一正確的方向。圍繞央行獨立性的政策手段和目標的種種質疑不應該成為我們打破央行獨立性的理由，畢竟，獨立的央行已經卓有成效地為全球經濟服務了40多年了。

約翰·雅尼斯·穆爾穆拉斯，希臘央行副行長，原財政部副部長。本文摘自貨幣金融機構官方論壇（OMFIF）出版的《The Bulletin (January 2017, Vol. 8 Ed. 1)》。OMFIF是一家總部位於倫敦的全球金融智庫。本文根據作者在兩次會議上的演講整理而成，分別為在東京舉行的JCER研討會與2016年11月在吉隆坡舉行的由SEACEN與OMFIF合辦的政策峰會。

英文原文：

Central Banks in an Unconventional Era

Monetary independence supports global economy

John Mourmouras

The intellectual roots of central bank independence can be traced back to the rational expectations revolution. This put forward the idea that people base choices on their rational outlook, past experiences and available information. Rational expectations played a pivotal role in breaking the intellectual deadlock with addressing the 『stagflation』 phenomenon of the 1970s, when high inflation was combined with high unemployment and slow growth.

Under discretionary monetary policy in a rational expectations framework, the interaction of private agents with the government generates an inflation bias, without any sustainable output gains. This bias increases with governments』 displeasure at the size of the output gap. As a result of this perceived bias, governments and central banks around the world moved to conduct monetary policy with a credible commitment to low inflation, anchoring inflation expectations to equally low levels.

Monetary policy in the post-crisis period

The financial crisis of 2008 and the ensuing European sovereign debt crisis have fundamentally changed the operational framework of independent central banks. Central banks have been given new macroprudential tasks, such as the supervision of systemic banks in economic and monetary union, conducted by the European Central Bank since 2014.

Another important change is that in the post-crisis era price stability is about preventing deflation, rather than halting excessive inflation. As a result, all major central banks have employed unconventional monetary policy tools in recent years. These include the provision of emergency liquidity and credit support to banks and extending the definition of assets accepted as eligible collateral when providing loans on a short- or medium-term basis.

To help raise inflation to targeted levels, central banks have turned to negative base rates and quantitative easing, considerably expanding central bank balance sheets. Since 2008 the Fed』s balance sheet has more than doubled, while the Bank of England』s has tripled. The ECB』s balance sheet has grown 66% since its QE programme started in 2015.

Central bank challenges for independence

The legacy of the 2008 crisis and subsequent low inflation have brought challenges for central bank independence. First, external parties have questioned the independence of central bank policy instruments. Second, even if these policies are not formally challenged, they may be less likely to achieve their objectives because of the altered conditions. Such questioning is arguably aimed at the wrong target. I believe criticism should not be directed against the very concept of independence, but rather against the current economic mix of ultra-loose monetary policy with tight fiscal policy.

Monetary policy naturally interacts with fiscal, structural and financial policies. The separate authorities that conduct these policies may be formally independent, but they are also interdependent. The risk of such interdependence is that, if one independent policy authority does not take appropriate action to meet its mandated objectives, the other authorities may be obliged to overreact to persistent shocks to meet their own objectives. This may result in a regime of 『weak dominance』 of other policies over monetary policy, effectively destabilising the regime of monetary dominance that central bank independence is meant to establish.

When interest rates are kept negative for too long, both the redistribution effects of monetary policy and the perceived degree of success of meeting the mandated objectives become more pronounced. This leads to greater demands for scrutiny of central bank independence. Concerns naturally arise about whether a monetary authority with an extended mandate of objectives can operate transparently and with appropriate accountability in a democratic political and economic system.

An independent central bank subject to checks and balances and democratic accountability needs public backing. When negative rates persist, central banks almost inevitably lose major parts of the necessary broad constituency of support.

There is still a strong overriding need for Independent central banks focused on price stability, capable of creating policy room for necessary structural adjustments, appropriate fiscal policies and macroprudential stability. All the theoretical and empirical arguments point in this direction: this approach offers the most promising path for the ultimate objective of restoring normal growth conditions and creating jobs. Controversy about the means and goals of central banking independence is no reason why the world should water down a concept that has served the global economy well over 40 years.

Prof. John (Iannis) Mourmouras is Deputy Governor of the Bank of Greece and a former Deputy Finance Minister.

This article appeared on The Bulletin (January 2017, Vol. 8 Ed. 1) by OMFIF. This is an abridged version of two speeches made in Tokyo at the JCER seminar and in Kuala Lumpur at the SEACEN Policy Summit, jointly organised with OMFIF, in November 2016. The Official Monetary and Financial Institutions Forum (OMFIF) is a global financial think tank headquartered in London.