爲什麼會有人買負收益率債券

Negative yielding debt is the most striking consequence of aggressive central bank policy. The amount of bonds with negative market interest rates is near $7tn and appears set to grow. Buying a bond with a negative yield, and holding it to maturity is a guaranteed way to lose money. So why would anyone do so?

負收益率債券是央行激進政策最令人矚目的後果。目前市場利率爲負的債券總計接近7萬億美元，且仍呈增長勢頭。購買收益率爲負的債券然後持有到期，絕對是個賠本買賣。那麼爲什麼有人會這樣做呢？

Because central banks will keep buying

因爲央行將繼續購買

Central banks have sought to stimulate economies through bond purchases. They hope to encourage lending by cutting borrowing costs, with the ultimate aim of boosting economic growth. Negative bond yields are a feature of this policy, not a bug.

各國央行試圖通過購買債券來刺激經濟。他們希望削減借款成本，以鼓勵放貸，最終目的是促進經濟增長。負收益率債券不是該政策的缺陷，而是它應有的特點之一。

The lower the yield on a bond, the higher its price. If a bond pays a coupon of 1 and has a price of 104, and it matures in a year at 100, the yield, or return, is negative. So negative yields are a simply a reflection of extremely high prices, which could be pushed higher by further demand such as central bank purchases.

債券收益率越低，其價格就會越高。如果債券的票息爲1，價格爲104，一年後以100的價格到期，收益率就爲負。因此負收益率只是反映了債券價格極高，而且可能被進一步需求——比如央行購買——推到更高水平。

Because you have to

因爲你不得不買

Institutions and investors which buy bonds and shares globally, are constrained by mandates, sets of rules dictated by the banks, pension funds or insurance companies from whom the money comes.

機構和投資者在購買全球債券和股票時，受到委託權限的限制，即銀行、養老基金或保險公司等出資方規定的種種規則。

The layered bureaucracy of the buyside can effectively force some investors to buy negative yielding debt. Money market funds, for example, typically invest in bonds up to a maturity of 13 months. For large amounts of the euro government debt market, bonds of a maturity shorter than this are negative yielding; German government bonds are negatively yielding up to a maturity of eight years.

買方的多層次官僚規則可能在實際上迫使一些投資者買入負收益率債券。例如，貨幣市場基金一般只可投資於到期時間不超過13個月的債券。在歐元區政府債券市場，符合這個要求的大量債券的收益率爲負值；到期時間8年或以下的德國國債收益率全部爲負值。

For some clients, regulatory requirements may force them to buy certain types of assets — banks, for example, are required to hold liquid assets.

對於部分客戶來說，監管要求可能會迫使他們購買某些特定資產，比如銀行就必須持有流動資產。

It’s better than holding cash

買它比持有現金好

Buying negative yielding debt might be considered similar to paying a government to guard your money in a vault. Government debt, though, is “liquid” — it can be bought and sold swiftly at little cost.

購買負收益率債券可能被視爲類似於付錢給政府，由其把你的錢守護在金庫裏。不過政府債務是“流動的”，以較小的代價就可以迅速買入和賣出。

Investors need returns, but they must balance this with a need for liquidity — providing their clients with rapid access to cash or cash-like assets.

投資者需要回報，但他們必須在回報需要與流動性需要（爲他們的客戶提供快速獲得現金或現金類資產的途徑）之間進行權衡。

Cash is the most liquid of assets. But central banks have imposed negative interest rates on cash deposits, which stands to trickle through to the rate banks charge institutional investors. A highly liquid but slightly negative yielding government bond might look more attractive by comparison.

現金是流動性最強的資產。但某些央行已對現金存款實行負利率，這會漸漸導致銀行對機構投資者的存款實行負利率。相比之下，收益率爲微小負值、但具有高度流動性的國債可能看起來更具吸引力。

Because the world is terrifying

因爲這個世界越來越可怕

Negative yields as a phenomenon reflect the challenges of central bank policy and expectations around economic growth. In a stagnant world, negative yielding bonds are both signal of and hoped for remedy to deflation.

負收益率債券現象反映了央行政策面臨的種種挑戰，以及圍繞經濟增長的預期。在經濟增長停滯的世界裏，負收益債券既是通縮的信號，也是人們指望的通縮解藥。

Global equity markets have been rocked by economic fears so far in 2016. Not only might these fears consolidate the view that growth will slow further and push bond prices higher — they may also encourage investors with some flexibility to move their allocations away from risky assets and towards havens, reasoning that a small loss will constitute “over-performance” if other asset classes take double-digit losses.

2016年以來全球股市受到經濟擔憂的震動。這些擔憂不僅可能強化這樣一個觀點，即增長將進一步放緩，推動債券價格走高，還可能鼓勵具有一定彈性空間的投資者把更多資產配置到避險資產、減持風險資產，其邏輯是：如果其他資產類別遭受兩位數的降幅，那麼小幅虧損將構成“超常表現”。

As fears grow, demand for haven assets grows. With bonds, this can push prices so high that yields turn even more negative. The supply of bonds, in a world where governments seek to curtail the levels of spending seen in the past, could also be constrained. These long-term dynamics could normalise permanently lower, if not negative, yields. They certainly seem different to the dynamics of the economies in which the modern bond market was shaped.

隨着擔憂加劇，對避險資產的需求也在增長。這會推高債券價格，導致收益率在負值區間進一步下行。在各國政府尋求將支出削減到以往水平的背景下，債券供應也可能會受到制約。這些長期動態可能令低收益率——即使不是負收益率——常態化。它們肯定與塑造現代債券市場的經濟動態不同。

What’s the downside?

負收益率債券有哪些缺點？

The danger, and one of the great ironies in a world of negative yielding bonds, is that prices for instruments designed to be safe and dull have become volatile. Consider the German 10-year Bund yield, not yet negative, which last spring unexpectedly surged back towards 1 per cent.

負收益率債券世界的危險和最大諷刺之一是，以安全和乏味爲設計宗旨的這類工具的價格變得波動。德國10年期國債收益率——尚未轉負——去年春天意外曾飆升到近1%的水平。

But ever lower yields mean capital gains — a reward for the continual risk of changing policy. Investors who bought German Bunds at the start of the year have made 4.2 per cent so far in 2016, according to Barclays government bond indices. Not a bad return, if the world is falling apart.

但是即便是較低的收益率也意味着資本收益，算是對政策不斷改變帶來的持續風險的回報。據巴克萊(Barclays)政府債券指數，今年初購買德國國債的投資者迄今已獲得4.2%的賬面利潤。這一回報還算不錯——假如世界正在分崩離析。