Monetary policy in a world of cryptocurrencies

加密货币世界中的货币政策

2019/04/30 15:00
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对照中文英文原文
加密货币已经吸引了消费者、政策制定者和媒体的注意。本专栏调查它们是否会危及央行的主要职能,即控制通胀和经济活动。

Cryptocurrencies have attracted the attention of consumers, policymakers and the media. This column investigates whether they can jeopardise the primary function of central banks, namely, controlling inflation and economic activity. Currency competition can succeed in calming inflation and preventing the sort of manipulation of interest rates and prices to which governments have historically been prone. But currency competition may also lead to government money losing the function of medium of exchange, which could be risky and lead government currency into further troubles.

加密货币已经吸引了消费者、政策制定者和媒体的注意。本专栏调查它们是否会危及央行的主要职能,即控制通胀和经济活动。货币竞争能够成功地抑制通胀,防止政府历来容易采取的那种利率和价格操纵。但货币竞争也可能导致政府货币失去交易媒介的功能,这可能是有风险的,并导致政府货币进一步陷入困境。

Can cryptocurrencies jeopardise the primary function of central banking – controlling inflation and economic activity – or at any rate limit their operational tools? The short answer is yes, they can.

加密货币是否会危及央行的主要职能——控制通胀和经济活动——或至少会限制它们的操作工具?简而言之,答案是肯定的。

Currency competition is not a recent phenomenon. Hayek wondered why government should be given the exclusive right to issue and regulate money, observing that it “…has certainly not helped to give us a better money than we would otherwise have had, and a very much worse one…” (Hayek 1976: 32). Things have changed since his time, and central banks in advanced economies have succeeded in controlling the value of their currencies and taming inflation.

货币竞争不是最近才出现的现象。哈耶克想知道为什么政府应该被授予发行和管理货币的专有权,他说,“……当然没有帮助我们获得比我们本来拥有的更好的货币,而且是一笔更糟糕的货币……”(哈耶克1976:32)。自他上任以来,情况已经发生了变化,发达经济体的央行成功地控制了本国货币的价值,遏制了通胀。

Money is not an object, and indeed, it can be quite imaginary – cryptocurrencies are digital, not physically minted. It is even misleading, as Hayek observed, to think of ‘money’ as a noun: “…it would be more helpful for the explanation of monetary phenomena if ‘money’ were an adjective describing a property which different things could possess to varying degrees” (p. 56).1

货币不是实物,事实上,它可以完全是想象出来的——加密货币是数字的,而不是实体铸造的。正如哈耶克所观察到的,把“钱”看作名词甚至是有误导性的:“如果‘钱’是一个形容词,描述不同的东西可以在不同程度上拥有的一种属性,那么它对解释货币现象将更有帮助。

To a certain or varying degree, cryptocurrencies have the same properties as traditional currencies, serving as medium of exchange, unit of account, and store of value. Chiefly, however, they function as a medium of exchange. Interestingly, monetary history offers other examples of uncoined money. As Luigi Einaudi (1936) noted, for centuries, ever since Charlemagne, an ‘imaginary’ money existed but served only as unit of account and never, unlike today’s cryptocurrencies, as medium of exchange.

加密货币在一定程度上或不同程度上具有与传统货币相同的属性,充当交易媒介、记账单位和价值储存手段。然而,它们主要起着交换媒介的作用。有趣的是,货币史提供了其他未创造货币的例子。正如路易吉•埃诺迪(Luigi Einaudi, 1936)所指出的那样,自查理曼大帝(Charlemagne)以来的几个世纪里,“假想”货币一直存在,但只是作为记账单位,从未像今天的加密货币那样作为交易媒介。

While digital and government currencies have some similar properties, government money also has special characteristics that today’s cryptocurrencies lack. Central banks also issue interest-bearing liabilities (reserves) and set policy in terms of this risk-free interest rate. Cryptocurrencies do not take the form of interest-bearing securities, and the growth in their supply is determined by an algorithm that allows new units to be minted. Government money is the liability of an agent, and the treasury can potentially back it by levying taxes. Digital currency is not the liability of any agent and has no fiscal backing.

虽然数字货币和政府货币有一些相似的属性,但政府货币也具有当今加密货币所缺乏的特殊特征。央行还发行有息负债(准备金),并根据这种无风险利率制定政策。加密货币不以有息证券的形式存在,其供应量的增长是由一种算法决定的,该算法允许铸造新单位。政府资金是代理人的责任,财政部可以通过征税来支持它。数字货币不是任何代理商的责任,也没有财政支持。

Recent monetary theory has shown that if central banks set the rate of interest, and are supported by fiscal backing, inflation can be targeted without causing any volatility in the price level aside from that due to fundamentals (Sims 1994, Woodford 2001). In these cases, government currency has a definite value. Unbacked cryptocurrencies, by contrast, can become worthless if everyone comes to believe they are.

最近的货币理论表明,如果中央银行设定利率,并得到财政支持,通货膨胀就可以有针对性地进行,而不会引起价格水平的任何波动,除了基本面因素(Sims 1994, Woodford 2001)。在这些情况下,政府货币具有一定的价值。相反,如果所有人都相信无担保加密货币的价值,那么它们就会变得一文不值。

Despite the privilege that government money enjoys, it can enter dangerous territory in the presence of currency competition, as I discuss in a recent paper (Benigno 2019).2 To understand the challenges posed by digital currencies, consider the extreme case in which government and private money can both provide the same liquidity services. In such a world, the money that prevails as medium of exchange will be the ‘better’ one, i.e. the one with higher return and lower inflation. If the growth of cryptocurrencies is slow enough, and they keep appreciating in value, they could easily become the more convenient token for transactions. That is, government money could lose the function of medium of exchange while still, for the reasons set out above, retaining value. But the loss of some of the properties of money could be risky and lead government currency into further troubles. Agents could begin to ask why debt contracts should be denominated in this inferior currency, or even why they should have to pay taxes in it. Government could lose its privilege and its currency could go out of business.

正如我在最近的一篇论文(Benigno 2019)中所讨论的,尽管政府资金享有特权,但在货币竞争中,它也可能进入危险的领域。要理解数字货币所带来的挑战,考虑一下政府和私人资金都能提供相同流动性服务的极端情况。在这样一个世界里,作为交换媒介的货币将是“更好的”货币,即回报更高、通胀更低的货币。如果加密货币的增长足够慢,而且它们的价值还在不断升值,它们很容易就会成为交易中更方便的代币。也就是说,由于上述原因,政府资金可能失去交换媒介的功能,但仍然保留价值。但货币的一些属性的损失可能是有风险的,并导致政府货币陷入进一步的麻烦。代理人可能会开始问,为什么债务合同应该以这种较差的货币计价,甚至为什么他们应该用这种货币交税。政府可能会失去特权,其货币可能会破产。

If anything, currency competition should improve the quality of government money. To avoid being supplanted by digital currency, central banks would need to achieve a sufficiently low inflation rate, lower than that of private money. Where the forces of competition are even stronger (say, in the presence of a significant number of private currencies), it is the strictness of entry barriers that determines the bounds on inflation. And in extreme but not unrealistic cases, these bounds can be very low, requiring almost negligible inflation if not outright deflation.

如果说有什么不同的话,那就是货币竞争应该提高政府货币的质量。为了避免被数字货币取代,央行需要实现一个足够低的通胀率,低于私人货币的通胀率。在竞争的力量更强的地方(例如,在存在大量私人货币的情况下),进入壁垒的严格程度决定了通胀的界限。在极端但并非不现实的情况下,这些界限可能非常低,即使不是完全通缩,也需要几乎可以忽略不计的通胀。

Currency competition can succeed in calming inflation and preventing the sort of manipulation of interest rates and prices to which governments have historically been prone – a result hailed by the proponents of currency liberalism. The demand for liquidity can be satiated and frictions and premiums in the transaction markets minimised. In fact, Hayek argued against the monopoly on money supply: “It has the defects of all monopolies: one must use their product even if it is unsatisfactory, and, above all, it prevents the discovery of better methods of satisfying a need for which a monopolist has no incentive” (Hayek 1976: 28).

货币竞争能够成功地抑制通胀,防止政府历来容易采取的那种利率和价格操纵——这一结果受到货币自由主义支持者的欢迎。流动性需求可以得到满足,交易市场的摩擦和溢价可以降至最低。事实上,哈耶克反对垄断货币供给:“它有所有垄断的缺陷:一个必须使用他们的产品即使是不满意,而且,最重要的是,它可以防止在发现更好的方法满足需要一个垄断者没有激励”(哈耶克1976:28)。

The recent financial crisis, however, has shown that the power of central bank money extends well beyond the property of medium of exchange. Central banks act as lenders of last resort to satisfy the liquidity needs of the economy, to make the financial system more resilient. What is more, the protracted situation of subdued inflation and zero interest rates has prompted the thesis that the inflation targets now being set by central banks are too low, and that a bit more inflation could be beneficial in avoiding liquidity traps as well as ‘greasing the wheels’ of the economy.

然而,最近的金融危机表明,央行货币的力量远远超出了交换媒介的性质。央行充当最后贷款人的角色,以满足经济的流动性需求,使金融体系更具弹性。更重要的是,抑制通货膨胀和零利率的旷日持久的情况促使论文,目前央行设定的通货膨胀目标过低,这一点通胀可能是有益的在避免流动性陷阱以及润滑车轮的经济。

These social objectives can be internalised only by a central issuer, such as government, and surely not by a plethora of ownerless private currencies, even if they operate in ideal competitive markets. The advent of digital currencies just as national borders are fading away in favour of a worldwide web for transactions definitely represents a serious challenge to current central banking. It should therefore not come as a surprise to learn that central banks are studying how to issue digital currencies of their own.

这些社会目标只能由中央发行机构(如政府)内部化,而肯定不能由过多的无主私人货币实现,即使它们在理想的竞争市场中运作。数字货币的出现,就在国界逐渐消失、全球交易网络取而代之之际,无疑对当前的央行构成了严重挑战。因此,当得知各国央行正在研究如何发行自己的数字货币时,我们不应感到意外。

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