经济学人财经 | 人人担忧公司债券市场的流动性，缘由何在？

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Why everybody is concerned about liquidity in the corporate-bond market

人人担忧公司债券市场的流动性，缘由何在？

In September 2007 Britain suffered its first bank run in a century. Television pictures showed a long queue of depositors outside a branch of Northern Rock. Alistair Darling watched in dismay from Portugal, where he and his fellow European Union finance ministers were gathered. “They’re behaving perfectly rationally, you know,” Mervyn King, the governor of the Bank of England, said in the smarty-pants manner that economists are cherished for. Mr Darling was uncharmed. “It was not what I wanted to hear,” he recalled.

2007年9月，英国遭受了本世纪以来的首次银行挤兑。电视画面显示储户在北岩银行一家支行门外排起了长龙，英国财政大臣阿利斯泰尔·达林(Alistair Darling)看到这个现象表示非常沮丧，当时他正在葡萄牙与欧盟各国财政部长开会。英格兰银行（英国央行）前行长默文·金（Mervyn King）认为“他们这样的表现非常合理”，且用一种经济学家所保有的自作聪明的方式说道。达林却觉得毫无意义。“这并不是我想听到的”,他回忆道。

What Lord King probably had in mind was a well-thumbed textbook model. Banks have a liquidity mismatch. One side of the balance-sheet is hard-to-sell loans; the other side is deposits that can be withdrawn in a trice. If depositors believe that a bank is sound, there will be no runs on it. But if enough start to demand their deposits back, it makes sense for everybody to join the rush.

大概金行长脑中所想的是一个老旧的教科书模型。银行存在流动性错配的现象：资产负债表的一侧是难以出售的贷款；另一侧则是瞬间就能被取走的存款。如果储户认为银行经营良好，则不会出现挤兑的情况；但如果很多人开始取回存款，那随之每个人都加入这场取款热潮似乎也显得合情合理。

This model can also be applied in other areas. Take the corporate-bond market. Every policy body of stature, from the IMF to the European Central Bank (ECB), has worried about a growing mismatch between investors’ expectations that they can sell out at any moment and an underlying shortage of liquidity in the market. More investors are using corporate-bond funds as an alternative to cash. But fewer dealers are willing to trade bonds in size. A big scare could feasibly start a run.

该模型也适用于其他领域。以公司债市场为例，从国际货币基金组织（IMF)到欧洲央行(ECB)，每一个政策机构都为日益加剧的流动性错配现象而担忧，投资者认为可随时抛售债券，而市场却存在潜在流动性缺乏。越来越多的投资者把公司债券当作现金的替代物。但是较少做市商愿意按照交易规模买卖债券。一场大恐慌将很容易引发挤兑。

The dynamics of capital-market runs are similar to those of bank runs. You see them in currency crises. Foreign-exchange reserves, say, are slim relative to the scale of local-currency assets held by flighty investors. Should enough of those investors sell out, others will soon follow. The result is a rout. There is a similar pattern with investment funds that promise speedy withdrawals but hold assets that cannot be sold quickly. Bad news prompts withdrawals. The speedy get paid. Other investors then try to get out, too. But the fund cannot sell assets fast enough. It is forced to suspend redemptions.

资本市场恐慌和那些银行挤兑的表现十分相似，也就是你所看到的货币危机。比如说，相比于反复无常的投资者们所持本币资产的规模，外汇储备量是相对小的。当有足够多的投资者选择卖出，其他人也会紧随其后。结果就是一场大溃败。一些承诺可以快速提款但是持有无法快速变卖资产的投资基金和这种模式也很相似。坏消息会刺激赎回，而只有动作快的投资者能成功赎回。其他紧接着试图退出的投资者，会因基金无法足够快速地变现资产而被迫暂停赎回。

Such trouble is especially likely with corporate bonds, which are inherently illiquid. In contrast with trading in shares, where buy and sell orders are matched on electronic order books, corporate bonds are traded over-the-counter. Bonds are not as standardised as shares. A company may have bonds of several different maturities. If you want to buy or sell, you call a dealer.

公司债券发生这种情况的可能性尤其大，因为公司债本身就缺乏流动性。股票的买卖交易是电子订单簿撮合，公司债券与股票交易不同，它是进行场外交易。债券不像股票那样标准化。一家公司可能有几种不同期限的债券。如果你想买卖，打电话给做市商。

The ease with which investors can trade bonds—the market’s liquidity—depends a lot, then, on the readiness of dealer banks to stockpile securities. Where there is heavy selling, dealers would ideally warehouse cheaper bonds for when people want to buy again. But since the financial crisis new rules have made it less cost-effective for banks to use capital for trading of any kind. The inventory of corporate bonds held by dealers has fallen sharply in the past decade (see chart).

因此，投资者交易债券的容易程度（市场的流动性），在很大程度上取决于银行间债市做市商持有证券的意愿度。当出现大量抛售时，做市商理想的做法是库存更便宜的债券，以备人们再次购买。但自金融危机以来，新规定降低了银行利用资本进行任何形式交易的成本效益。过去10年，做市商持有的公司债券存量急剧下降(见图表)。

As the role of dealers has shrunk, the thirst for instant liquidity has increased. Derisory yields on the safest government debt have drawn investors towards riskier securities, including corporate bonds. A cheap and convenient way to invest in them is to buy an exchange-traded fund, or etf. These are low-cost investment funds that hold a basket of bonds, usually mirroring a benchmark index. They trade on stock exchanges just as listed shares do. The ease of buying and selling bond etfs is a big part of their appeal. They are also often used as for spare cash. Studies are divided on whether etfs make the underlying bonds more or less liquid. But there are concerns that in a stressed market, outflows from etfs might make a bad situation worse.

随着做市商角色被削弱，客户对即时流动性的需求不断增强。最安全的政府债券收益率低得可笑，导致投资者转向风险更高的证券，包括公司债券。一种便宜又方便的投资方式是购买交易所交易基金(ETF)，即以低成本持有一篮子债券的投资基金，通常以复制基准指数所持有的债券。他们像上市股票一样可在证券交易所交易。债券ETF的买卖便利性是它们的一大优势。他们也经常作为闲置现金的投资标的。关于ETF是否使标的债券更具流动性的研究存在分歧。但有人担心，如果在一个流动性压力较大的市场，ETF造成的资金外流可能会让本就糟糕的情况雪上加霜。

And it is not hard to make a case that the corporate-bond market has become more fragile. Many firms in America have issued lots of bonds to buy back their own shares. With extra leverage comes more risk. Half of all investment-grade bonds have a credit rating of bbb. In a recession a chunk of those bonds will be downgraded to junk. Many mutual funds and etfs can hold only investment-grade bonds. If a lot of bonds have to change hands quickly, that could easily overwhelm the market’s limited liquidity. Prices might fall a long way.

可以说公司债券市场已经变得愈发脆弱。美国许多公司通过发行大量债券来回购自己的股票，而这种额外的杠杆带来更大的风险。所有投资级债券中有一半的信用评级为bbb（注：bbb或baa以上的债券都被认为是投资级债券。信用等级较低的如bb或ba以下的债券则被认为是投机级债券或垃圾债券。）在经济衰退期间，这些债券中的一大部分将被降级为垃圾债券。许多共同基金和ETF中只能持有投资级债券。如果市场中大量债券都要求极高的换手率，那将很容易超出市场有限的流动性。从而可能导致债券价格不断下滑。

Just how messy the next big shake-out in the corporate-bond market is depends on many things: on how weak the economy gets; on how many bbb borrowers can avert a downgrade; on how quickly funds can be raised to buy at fire-sale prices. For now, it seems rational to hold bonds that afford a little extra yield. Smart-alecks say this will surely end badly. But who wants to hear that?

下一次公司债券市场震荡的混乱程度取决于很多因素：经济的脆弱程度；能够避免降级的bbb投资级债券的数量；募集大量资金并以低价买入的速度。就目前来看，持有能够产生一点额外收益的债券似乎是合理的，虽然有些自作聪明的人说这肯定会以糟糕的结局收尾。但是谁愿意听到这些呢?

翻译组： 

Vivian，女，金融硕士，爱潜水爱运动

Summer，女，QE在职，梦想能仗翻译/音乐 /健康走天涯

Gloria，女，经济学在读，爱健身爱电影爱古怪新奇的事物

May ，男， 跨界财经、法律、政治，热恋越野跑，迷恋经济学人

校对组：

Emily，食物链底端金融民工，经济学人粉丝

Ashley，女 ，金融硕士，爱宠物 爱英语，爱旅游，经济学人粉丝