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社论 | 失控

英文部分选自经济学人20230204期社论版块

Leaders | Out of control

社论 | 失控

The Bank of Japan should stop defending its cap on bond yields

日本央行应放弃债券收益率上限

“Yield-curve control” has left the central bank facing huge losses

“收益率曲线控制”让日本央行面临巨大损失

Changing the helmsman halfway through a tricky manoeuvre at sea is a risky prospect. Yet that is what is happening in Japan, where the government will soon propose a successor to Kuroda Haruhiko as the head of the Bank of Japan, just as the central bank prepares to tighten monetary policy for the first time since 2007. In December, amid rising inflation and speculative pressure, the bank raised its cap on ten-year government-bond yields, from 0.25% to 0.5%. The next governor is expected to raise the cap further, or even to abandon the policy, which is known as yield-curve control.

在海上进行高难度机动时，半途更换舵手是十分危险的。然而，日本正打算这般操作：政府将很快提名央行行长黑田东彦（Kuroda Haruhiko）的继任者；而央行正准备自2007年之后再度收紧货币政策。去年12月，面对不断上升的通货膨胀和投机压力，央行将10年期国债收益率上限从0.25%提高到0.5%。预计下任行长将进一步提高上限，甚至放弃收益率曲线控制政策。

Unfortunately, the regime change is not off to a good start. Lifting the cap has only increased bets against it. Since December the Bank of Japan has had to defend the higher cap by buying bonds worth a staggering $240bn, nearly 6% of Japan’s gdp and about three times the pace of purchases in the preceding three months. The bank seems determined to keep the cap in place until a change of leadership is complete. Doing so is a costly mistake. It should change course now.

不幸的是，改朝换代开局不顺。上调债券收益率上限引来了更多的投机者。引来了更多做空者。去年12月以来，为了守住0.5%的新上限，日本央行吃进了价值2400亿美元的债券，几乎占日本GDP的6%，大约是之前三个月购买速度的三倍。央行似乎决心在领导层换届完成之前保住这一上限。但这是一个代价高昂的错误；日本央行应该立刻转变路线。

Yield-curve control has been the most awkward part of the monetary-policy toolkit developed after the global financial crisis of 2007-09. Having run out of space to cut short-term interest rates, central banks tried to drive down long-term bond yields instead. To that end, they bought bonds with newly created money. By 2016, however, the Bank of Japan’s balance-sheet was ballooning, and it introduced a yield cap in the hope of keeping yields low while making fewer purchases. The idea was that yields would adjust purely on the expectation that the central bank would act if necessary to enforce the cap. And for a time, the policy worked as intended.

2007-09年全球金融危机后诞生的一大批货币政策工具中，收益率曲线控制一直是最拙劣的那个。由于短期利率已触底，各国央行转而试图压低长期债券收益率。为此，各国央行发行新货币来购买债券。然而，到2016年，日本央行的资产负债表持续膨胀，它引入收益率上限，希望在减少购买的同时保持低收益率。当时的想法是，只要市场预期央行会在必要之时采取措施守住上限，收益率就会自行调整。之后的很长一段时间里，情况也确实如此。

As inflation has risen, however, such caps have lost their credibility. In 2021 Australia suddenly abandoned its experiment with yield-curve control as investors began betting that interest rates would need to rise to fight inflation.

然而，随着通胀加剧，设定上限已经唬不住人了。2021年，随着投资者开始押宝央行为抑制通胀将不得不加息，澳大利亚突然中止了控制收益率曲线的尝试。

In Japan the situation is more finely poised, because inflation has been too low for decades and ongoing stimulus may be necessary to ensure the Bank of Japan hits its 2% inflation target over the next few years. But Japan’s policy is far more aggressive than Australia’s, which capped bonds at a three-year, rather than a ten-year, horizon. A small change in the outlook for the next decade is enough to bring a ten-year cap under pressure.

而日本的情况更为微妙。几十年来，日本通胀一直维持在过低水平，为了确保在接下来的几年将通胀维持在2%的目标上，日本央行可能需要出台持续性刺激政策。但是日本的政策远比澳大利亚更为激进：后者对3年期债券进行收益率控制，而日本是10年期债券。10年是如此之长，以至于对未来的预期发生微小的变动，都足以对10年期债券收益率上限造成压力。

Investors know that Mr Kuroda’s successor is likely to adjust and eventually abandon the policy—especially if it is a hawk, such as Yamaguchi Hirohide, a former deputy governor. The result has been rampant speculation, forcing the bank to hoover up more bonds: exactly what yield-curve control was supposed to avoid. The bank now owns more than half the Japanese government-bond market, including two-thirds of bonds with a maturity between one and 11 years. Bizarrely, its accounts imply that it owns more than 100% of the issuance of some bonds, having lent out its purchases only to buy them back again.

投资者们认为黑田东彦的继任者很可能会调整并最终放弃该政策——如果是前副行长山口裕英（Yamaguchi Hirohide）这样的鹰派接手，可能性就更大了。这导致市场投机活动猖獗，逼迫央行吸收更多债券，极大违背了收益率曲线控制政策的初衷。目前，央行已占据日本政府债券市场的大半壁江山，持有三分之二到期时间从1年到11年不等的债券。古怪的是，央行账户显示其拥有部分债券发行量的100%以上，说明其逆回购后释放的流动性又以购买国债的方式回流央行。

For investors, selling bonds to the bank seems a one-way bet. Yields move inversely to prices. Why own a bond that will fall in value as the cap is lifted, if you can sell it for a higher price today? But for the Bank of Japan the purchases could prove correspondingly costly. We calculate that a rise in bond yields of just 0.25 percentage points would cause paper losses of over $60bn. The bank’s cash flows will suffer if short-term rates rise before the bonds mature, forcing the bank to pay interest on the reserves it has created in the banking system to finance its purchases. With every bond bought, the potential loss mounts.

对投资者而言，把债券卖给央行是稳赚不赔的买卖。收益率与价格成反比。如果一个债券就要因为收益率上升而贬值，为何不在今天将其卖出？但对日本央行而言，投资者赚了多少，自己就得赔多少。根据我们的计算，债券收益率上升仅0.25个百分点就会造成超过600亿美元的账面损失。如果短期利率在债券到期前上升，央行的现金流将会受到影响，因为央行需要创造出超额准备金以买入债券，并这部分超额准备金支付利息。

Some argue that the yield cap must be maintained until after wage negotiations in the spring, so that it stimulates average pay rises high enough to be consistent with price growth of 2%, ensuring Japan’s escape from decades of low inflation. But the limited extra stimulus brought about by the cap is not worth the possible losses, which pose a threat to taxpayers. Instead, the central bank’s most important tool is its short-term interest rate, which it can still pledge to keep low to act as a stimulus.

一些人认为，收益率上限至少要保持到春季工资谈判之后，以刺激平均工资匹配2%的价格上涨，确保日本摆脱几十年的低通胀。但是与潜在的损失相比，保持上限带来的有限的额外刺激实属得不偿失，反而会给纳税人带来威胁。相反，央行最重要的工具是短期利率：其仍可承诺保持低利率以刺激经济。

Signalling the end of a price peg is unwise, because it attracts speculation and forces a messy exit. It is too late to avoid that. Everyone knows that the end of yield-curve control is coming in Japan. The central bank—whoever is at its helm—can at least kill off the policy before it loses a lot more money. ■

发出结束价格挂钩的信号并不明智，因为这会刺激投机，并使退出过程混乱不堪。当然，现在说这些也没有用了：人人皆知日本的收益率曲线控制政策即将终结。但亡羊补牢，为时未晚，不管谁来掌舵，日本央行仍能尽早取消这一政策，及时止损。

翻译组：

Dossver，男，是错永不对真永是真
Yo，女，种下过流星，立志不做大鸵鸟

Humi，在躺平、侧卧和睡梦中寻找诗和远方

校对组：

Ithil，胡辣汤爱好者

Alison，“贪玩又自由的风筝”

Hannah，做个废柴，保持愉快

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