百年债券？为何全球已有14个国家发行“超长期”国债

全球主权债券收益率现正卡在接近历史低点的水平，上周三德国首次发行了收益率为负的30年期国债。

虽然债券市场可能预示着全球经济走向衰退，但各国政府越来越渴望利用借贷成本降到历史低点的机会筹集资金，填补近乎持续的赤字。

这很可能是美国财政部为何低调提到正在尝试推出“超长期”国债，即发行之日起50年或100年后到期的政府债券。目前，美国政府发售的国债最长期限是30年。

美国政府之所以意识到现在是重新讨论“超长期”国债的好时机，创纪录的低利率肯定是关键原因之一，如此一来政府就能够锁定未来数十年的低资本成本。但是，长期利率的下降实际上已经持续一段时间，“世纪债券”这种比人类平均寿命还要长的债券反映出至关重要的事实，那就是人口老龄化和出生率下降，在悲观主义者看来意味着经济逐渐僵化。

“全世界出现剧烈的人口结构变化。”在旧金山联储近日发布的一份研究报告中，卡洛斯·卡瓦略、安德烈·费雷罗和费尔南达·内希奥写道。“在大多数发达经济体中，实际寿命和预期寿命都已经稳步增加。预期寿命的增加将会拉长个人的退休时间，从而促使人们在整个生命周期中更愿意储蓄而非消费……预期寿命的增加给利率带来了下行压力。”。

“债券的主要买方是企业养老金计划和保险公司。”康桥汇世的投资组合经理亚历克斯·尼珀说道。“尤其企业养老金正转向对冲负债而非扩大资产基础，所以会倾向于找期限更长的债券。”

过去几年，包括富裕的大学和医疗保健网络在内的少数大公司已经注意到趋势，纷纷发行了百年债券。2014年克利夫兰诊所就已经发行了超长期债券，而宾夕法尼亚大学也在上月发行了定于2119年到期的债券，收益率为3.61%。同日，30年期美国国债的收益率约为2.5%。

这表明收益率曲线变平（意味着长期借贷的成本不会远高于短期借贷）刺激发债方借债50年或100年，而非20年或30年。在经济合作与发展组织的34个成员国中，已经有14个国家发行了期限从40年到100年不等的主权债券。而且随着欧元区借贷成本的下降，过去两年奥地利、比利时和爱尔兰纷纷发行了百年债券。值得注意的是，发行方大多是人口增长放缓且国民寿命增长的国家。

美国财政部在8月20日的提议并不是第一次有意推出超长期债券，早在上一次金融危机过后，奥巴马政府就提出并讨论过这个问题，而在2017年，现任财政部部长史蒂文·姆努钦也曾经提出过相同想法。

今年早些时候，美国财政部甚至提出了发行永久债券的想法，永久债券没有到期日，但会永远支付利息（中世纪时期大多数债券均是如此运作，但情况并不一样）。

不过，就在30年期国债收益率史上首次跌破2%的当天，美国财政部决定尝试发行超长期国债，这无疑让市场观察人士吃了一惊。

“这不是美国财政部的常规做法，比较出人意料，选择在8月中旬流动性较低的周五下午，还跳出了两周半以前刚刚发布的季度旧债换新指引。”美银美林的美国利率策略主管马克·卡巴纳说道。“我们不确定美国财政部发布该声明的原因，但可能反映政府希望利用处在历史低位的长期利率，抵抗收益率曲线倒挂造成的经济衰退忧虑。”

然而，看起来银行界对该想法似乎热情不大。

“之前美国财政部多次研究过发行长期国债的问题，每次结论都是不符合纳税人的最佳利益。” 卡巴纳补充道。“2017年研究时，他们发现没有证据表明市场对期限超过30年的国债存在强劲或是可持续的需求。我们认为，财政部本轮试探也不会得出什么新结论。”

美国财政部网站显示，下属的债务管理办公室正在就超长期债券“联系市场，以了解市场对超长债券的最新看法”，咨询完成后再决定是否采取行动。（财富中文网）

译者：艾伦

审校：夏林

Sovereign bond yields across the globe are stuck nearall-time historic lows, with Germany issuing negatively-yielding 30-year debtfor the first time ever on last Wednesday.

While bond markets may be signalling recession ahead for the global economy, governments around the world are increasingly eager to take advantage of historic low borrowing costs to fund their near continuous deficits.

That’s likely one reason why the US Treasury quietly mentioned last Friday that it was putting out feelers for “ultra-long” Treasury bonds—meaning government debt that would mature 50 or 100 years from the date of issuance. Currently, the longest maturity of sovereign debt that the US government sells is 30 years.

Record low interest rates are certainly a crucial reason why the US government sees an opportunity to reopen the conversation around ultra-long bonds, given the opportunity to lock in a low cost of capital for decades to come. But considering that long-term interest rates have actually been falling for some time now, “century bonds” or debt dated longer than the average human lifespan crucially reflects how our populations are aging, our birth rates declining, and to pessimists, our economies ossifying.

“The world is undergoing a dramatic demographic transition,” wrote Carlos Carvalho, Andrea Ferrero, and Fernanda Nechio in a recent research piece for the Federal Reserve Bank of San Francisco. “In most advanced economies, actual and expected longevity have increased steadily. An increase in life expectancy would lengthen individuals’ retirement period, generating additional incentives to save rather than spend throughout the life cycle… and increase in life expectancy puts downward pressure on rates.”

“The primary consumer of these bonds would be corporate pension plans and insurance companies,” said Alex Nepper, portfolio manager at Cambridge Associates. “Corporate pensions in particular have shifting towards hedging their liabilities overtime as opposed to growing their asset base, so they would look for longer-dated debt.”

A handful of large companies including wealthy universities and health care networks have already caught on and issued century-long debt in the past years. Among many others, that includes the Cleveland Clinic in 2014and most recently the University of Pennsylvania, which last month issued abond that matures in 2119 and yields 3.61%. On the same day, US Treasury bondsdated 30 years yielded around 2.5%.

That goes to show how a flat yield curve (meaning it doesn’t cost much more to borrow for longer periods of time) incentivizes borrowing for 50 or 100 years rather than 20 or 30 years. Already, fourteen countries inside the 34-country strong OECD have issued sovereign debt with maturities ranging from 40 to 100 years, and Austria, Belgium, and Ireland have all issued century-bonds within the past two years as Eurozone borrowing costs have declined. Notably, these countries are predominately made up of countries with slowing population growth and increasing lifespans.

August 20’s proposals were not the first time that the US government has toyed with the idea of ultra-long bond. After the financial crisis they were put up for discussion by the Obama Administration, and they were reproposed in 2017 under Treasury Secretary Steven Mnuchin.

Earlier this year the Treasury Department even tabled the idea of issuing perpetual bonds. That is, bonds that never mature but pay interest into eternity (the way most bonds worked around the Middle Ages, but that’s another story).

Still it definitely took market watchers by surprise when news on a new exploration of ultra-long issuance broke on the same day that after the 30-year yield fell below 2% for the first time ever.

“This is a surprising break from typical Treasury practice since it was unexpected, late on a mid-August Friday in low liquidity, and outside of quarterly refunding guidance that was just provided 2.5 weeks earlier,” said Mark Cabana, CFA, heads of US rates strategy at Bank of AmericaMerrill Lynch. “We are not sure why Treasury delivered such an announcement but expect it reflects a desire to take advantage of historically low long-dated interest rates, and push back on recession concerns from an inverted yield curve.”

However, there doesn’t appear to all that much enthusiasm within the banking community about the idea this time around, either.

“Treasury has studied ultra issuance numerous times in the past and has always concluded it was not in the best interest of the taxpayer,”Cabana added. “In their 2017 study, they did not see evidence of strong or sustainable demand for maturities beyond 30 years. We doubt Treasury's conclusions from upcoming outreach will be materially different.”

Per the US Treasury’s website, the Treasury’s Office of Debt Management is currently conducting “market outreach to refresh its understanding of market appetite” for ultra-long debt and will take a decision whether to proceed following that consultation.