Elvin Mirzayev 2016年7月14日
负利率的想法看起来很奇怪而且不能用经典金融和经济理论来解释，因为经典金融和经济理论都是建立在正预期回报上的假设。传统上，投资者有规避风险的特性并且在各个风险水平需要获得不同的回报增量。
但是现在我们发现有负央行存款利率和负收益政府和公司债券的出现，并且有投资者购买这些证券。这是为什么呢？
欧洲央行的负存款利率
央行将负存款利率当作一个阻止央行出现超额资金的货币政策。
例如，今年3月欧洲央行（ECB）将存款利率设置为-0.4%。这是一个改变利率中极其极端的货币政策，与央行削减利率刺激经济活动很相似。
欧洲国家现在正与负通胀率作斗争，欧洲央行选择将存款利率降低到负值以推动过剩资金投入到经济中。他们的目标是银行将会受到负利率存款的刺激从而使用资金将基准利率维持在0，将回购利率维持-0.1%。瑞士和丹麦央行也同样采用了负利率作为货币政策工具。
负收益债券
在上周，德国首次将10年期债券的收益率设定为负值。负债券收益表明投资者愿意支付费用去持有德国债务。现在全球负收益债券的数量超过8万亿美元。
投资负收益债券的原因如下：
u 扩大的负收益预期。在当前通货紧缩的经济环境下，购买负收益债券的投资者可能会期望债券的收益率进一步降低，使他们能够从投资中获利。
u 正收益的可能。在预计会发生通货紧缩的经济中，投资负收益债券的投资者可能会获得实际的正收益。
u 重新分配资金减少负收益。因为一些央行的实行的负利率高于政府债券的负收益，投资者更情愿从央行取出资金投资债券，这将减少损失。
u 分配策略。一些机构投资者需要在其投资组合中持有债券，特别是那些专注于固定收益投资的投资者，他们可能需要投资负收益债券以满足分配政策。
u 货币升值预期。一些投资者估计某些货币会相对本国货币计价的负利率债券升值，他们认为投资会带来本国货币的正收益。例如，加入A国债券收益率比B国高负收益率债券高，但是投资者预计B国货币会相对A国货币升值，这样投资B国债券带来的回报可能高于投资A国债券。
u 资金安全考虑。新兴市场国家的投资者在经济衰退中举步维艰，随时面临着违约和货币贬值，他们将会愿意购买欧洲经济大国的债券避险，例如德国和瑞士等。
总结
欧元区与通货紧缩的斗争导致了令人费解的负收益债券和负央行存款利率的出现。很难解释投资者为什么会投资这些确定会出现损失的工具，但是可能的原因是：扩大的负收益预期、通货紧缩预期的加大、货币汇率变化和寻求安全投资。
The Negative Rates of Europe's Central Banks
By Elvin Mirzayev, CFA, FRM | Updated July 14, 2016 — 11:22 AM EDT
The idea of negative interest rates seems strange and isn't explained by classic financial and economic theories, which are all built on the assumption of positive expected return. Traditionally, investors are risk averse and require a positive incremental return for every level of risk taken.
But now that we are seeing negative central bank deposit interest rates and government and corporate bonds with negative yields, there are investors buying into these securities. Why?
Negative Deposit Rates Of Europe's Central Banks
Central banks apply negative interest rates to the deposit as a monetary policy tool to discourage banks from depositing their excess cash with the central banks.
For example, the European Central Bank (ECB) set depositary rates at -0.4% this past March, meaning that it was penalizing banks that hold excess cash with the central bank. It’s an extreme execution of monetary policy, which includes changing interest rates, much like when central banks decrease the rates to stimulate economic activity.
EU countries are currently battling negative inflation i.e. deflation, and the ECB chose to decrease deposit interest rates below zero in order to push banks' excess cash into the economy. The expectation is that banks will be discouraged from negative investing and instead will use the funds to maintain the reference rate at zero and the repo rate at -0.1%. Central Banks of Switzerland and Denmark also apply negative yields as a monetary policy instrument.
Negative Yielding Bonds
Just this past week, Germany began auctioning 10-year bonds at negative yield for the first time. Negative bond yields imply that investors are willing to pay the German government to hold its debt. Including Brexit, there are now over $8 trillion in negative-yielding bonds in the world.
The rationale behind investing in bonds that offer a guaranteed loss:
Widening negative yield expectation - Under the current deflationary economic environment, investors who purchase negative yielding bonds may expect the yields to decrease even further, enabling them to profit from the investment.
Possibility of a positive real return - In economies where deflation is expected, investors may end up with positive real yield by investing in negative yield bonds.
Reallocating cash from more negative to less negative - Since some central banks apply negative yields that are higher than negative government bond yields, investors prefer to withdraw cash from central banks and invest in government bonds which will cost less.
Policy allocation – Some institutional investors are required to maintain bonds in their portfolio - particularly investors who specialize in fixed income security investments like bond mutual funds - and they may keep investing in negative yielding bonds in order to be in line with that policy allocation.
Currency appreciation expectations – Foreign investors who expect an appreciation of currency against a domestic currency-denominated bond with a negative yield would agree to invest for the positive expected return in the domestic currency. For example, if Country A's bonds has a higher yield than Country B's negative yield bonds, but investors expect Country B's currency to appreciate in value relative to Country A's currency, investing in Country B's bonds may result in higher returns.
Paying for safety - Foreign investors from emerging countries struggling with economic downturns, accompanied by defaults and currency devaluation, would agree to safe-haven buying bonds with negative yields in Europe's economic giants like Germany, Switzerland etc.
The Bottom Line
The Eurozone's fight with deflation results in inexplicable negative bond and central bank deposit rates. It’s difficult to see why investors would be willing to invest in instruments that offer a guaranteed losses, but possible reasons are: negative yield widening expectations, increasing deflation expectations, currency rate change and seeking safe investments.
本文翻译由兄弟财经提供
文章来源：http://www.investopedia.com/articles/investing/040215/understanding-negative-rates-europes-central-banks.asp