Investors should not fear a stockmarket crash

Take a long view, and shares are a lot less risky than many realise
从长远来看，股票的风险比许多人意识到的要小得多

2024年10月24日 05:34 上午

SHAREHOLDERS ARE enjoying one of their best runs in history. Since a trough last October the S&P 500 index of large American firms has risen by more than 40%; peers in Europe, Japan and Canada have all gone up by at least half as much. The fears of last year, that stubborn inflation would prevent central banks from cutting interest rates, keeping bond yields high and dragging share prices down, have all but vanished. In fact, many of the world’s monetary guardians have been slashing borrowing costs just as corporate profits have climbed and animal spirits have surged. The result is that plenty of stockmarkets are now hovering near all-time highs.

股东们正在享受历史上最好的业绩之一。自去年 10 月触底以来，美国大型企业标准普尔 500 指数已上涨 40% 以上；欧洲、日本和加拿大的同行都上涨了至少一半。去年人们对顽固的通货膨胀将阻止央行降息、使债券收益率保持在高位并拖累股价下跌的担忧几乎消失了。事实上，随着企业利润攀升、动物精神高涨，世界上许多货币守护者一直在削减借贷成本。结果是，许多股市现在徘徊在历史高点附近。

Accordingly, investors are engaged in the activity that is traditional for such moments: not sending champagne corks flying, but obsessing about whether the good times are already over. They are hardly short of reasons to fret. Relative to underlying profits, American stocks have rarely been pricier, and then only before big slumps. Unnervingly, more than a third of the S&P 500’s market value is concentrated in just ten firms. Spurred on by rich-world governments’ insatiable appetite for borrowing, and especially the prospect of Donald Trump entering the White House and sending America’s deficit even higher, bond yields are again rising quickly. Volatility is up, too, and gold—typically seen as a hedge against chaos—has been on a rally for the ages·. A crash would need a catalyst. But a lot of other potential causes are already in place.

因此，投资者会进行这种时刻的传统活动：不是把香槟瓶塞吹飞，而是担心好时光是否已经结束。他们不乏理由担心。相对于基本利润，美国股票的价格很少如此，而且只有在大幅下跌之前才如此。令人不安的是，标准普尔 500 指数超过三分之一的市值集中在这十家公司中。受富裕国家政府贪得无厌的借贷胃口，尤其是唐纳德·特朗普入主白宫、推高美国赤字前景的刺激，债券收益率再次快速上升。波动性也在上升，而黄金——通常被视为对冲混乱的工具——多年来一直在上涨。崩溃需要催化剂。但许多其他潜在原因已经存在。

Here, then, is a reason to be cheerful should you end up watching a big chunk of your portfolio go up in smoke. Naturally, this would be unpleasant. Yet the nicest result of the past few decades’ academic research on finance is that, at least in the long run, it matters less than you might think. The reason is that stocks are more like bonds than most investors realise. As prices (or, more precisely, valuations) fall, expected returns rise.

那么，如果你最终看到你的投资组合的很大一部分化为乌有，这就是一个值得高兴的理由。这自然会让人不愉快。然而，过去几十年金融学术研究的最好结果是，至少从长远来看，它的重要性并不像你想象的那么大。原因是股票比大多数投资者意识到的更像债券。随着价格（或更准确地说，估值）下降，预期回报率上升。

For bonds, this is easy to see. Just consider what happened in 2022. Interest rates rose by several percentage points, dragging up bond yields with them. To align existing bonds, many of which paid next to no interest, with prevailing yields, prices were hammered. After all, investors would buy bonds only if they were sufficiently discounted from face value to make up for their low coupons. Viewed this way, American Treasuries had their worst year in over a century. Unless they sold after the crash, though, this would not have altered their owners’ returns by one jot. If they held their Treasuries to maturity, they would still receive every coupon they had been promised, followed by the repayment of principal.

对于债券来说，这一点很容易看出。想想2022年发生的事情吧。利率上升了几个百分点，拖累了债券收益率。为了使现有债券（其中许多债券几乎不支付利息）与现行收益率保持一致，价格受到了打击。毕竟，只有当债券的票面价值有足够的折扣以弥补低息票时，投资者才会购买债券。从这个角度来看，美国国债经历了一个多世纪以来最糟糕的一年。不过，除非他们在股市崩盘后出售，否则这不会对他们所有者的回报产生一丝一毫的影响。如果他们持有国债至到期，他们仍将收到承诺的每张息票，然后偿还本金。

It is not obvious that stocks behave similarly—for one thing, there is no repayment of principal to make up for a drop in prices. Even so, they do, concluded a panoramic survey of asset-price research published in 2011 by John Cochrane, then at the University of Chicago. The ratio of profits to share prices, once thought to forecast future earnings, in fact does not. What it does predict, much like the yield on a bond, is the shareholder’s expected return. Unlike a bond yield, this is not a sure thing: realised returns might fall on either side of the forecast. Thankfully, as is the case with bonds, investors are compensated for falling share prices with higher expected returns.

股票的表现是否相似并不明显——一方面，没有偿还本金来弥补价格下跌。即便如此，当时在芝加哥大学工作的约翰·科克伦 (John Cochrane) 在 2011 年发表的一项资产价格研究全景调查中得出结论，他们确实这么做了。利润与股价的比率一度被认为可以预测未来收益，但事实上并非如此。它所预测的，就像债券的收益率一样，是股东的预期回报。与债券收益率不同，这不是确定的事情：实现的回报可能会落在预测的两侧。值得庆幸的是，与债券的情况一样，投资者可以通过更高的预期回报来补偿股价下跌。

约翰.科克伦 图源:johnhcochrane.com

Armed with this information, one class of investor should welcome a crash. Sky-high stock valuations have badly eroded the returns youngish savers can expect to earn as they age. In a recent note, analysts at Goldman Sachs, a bank, put this into grim numbers. Based on valuations and factors such as market concentration and interest rates, they forecast annualised nominal returns of just 3% for the S&P 500 over the coming decade, compared with a historical average of 11%. A painful crash might at least reset the dial and give youngsters a better chance of retiring at some point.

有了这些信息，一类投资者应该会欢迎崩盘。极高的股票估值严重侵蚀了年轻储户随着年龄增长所能获得的回报。高盛银行的分析师在最近的一份报告中将这一数字表述为严峻的数字。根据估值以及市场集中度和利率等因素，他们预测未来十年标准普尔 500 指数的年化名义回报率仅为 3%，而历史平均水平为 11%。一次痛苦的车祸至少可能会重置表盘，让年轻人在某个时候退休的机会更大。

The broader implication is that anyone holding stocks for the long run—in a pension pot, say—is taking less risk than they might think. Investors often imagine year-by-year returns as like a series of independent coin tosses, in which a run of poor luck implies nothing at all about the odds of the next flip. In this world a crash is simply terrible news. Reality is more pleasant. Investing in stocks is like flipping the coin of the gambler’s fallacy: a long series of tails really does make it more likely that you will come up heads next time. Cold comfort, perhaps, when prices are plunging and some of your savings have disappeared. But a good reason to buy at the bottom.■

更广泛的含义是，任何长期持有股票的人（比如养老金）所承担的风险都比他们想象的要小。投资者常常把逐年的回报想象成一系列独立的抛硬币，其中连续的运气不佳并不意味着下一次抛硬币的可能性。在这个世界上，车祸简直是可怕的消息。现实更令人愉快。投资股票就像赌徒谬论中掷硬币一样：一长串的反面确实会让你下次出现正面的可能性更大。当物价暴跌、你的一些积蓄消失殆尽时，这或许是一种冰冷的安慰。但这是在底部买入的充分理由。■