每年年底，經濟學家們都要對來年的經濟形勢進行一番展望，今年自然也不例外。在對今年的展望中，他們把可能影響全球經濟的風險因素基本上都寫了進去，最重要的一個風險點，是中美尚未達成實質性的經貿協定。不斷增長的企業債務也是一個重要風險點。此外還有中國經濟的下行風險尚未扭轉、英國脫歐的久拖不決等等。

在大多數經濟學家的眼中，特朗普被彈劾（甚至有可能提前下臺）則只不過是小事一樁。然而就在新年伊始，美國出人意料地在伊拉克發動空襲，殺死了伊朗軍方的最高指揮官，將長期敵對的美伊兩國正式拉到了戰爭邊緣。這樣的戲碼，就連最悲觀的預言家也是預測不出來的。

現在，我們進入2020年還不到一周的時間，全球市場已經面臨著與2019年截然不同的考驗。

在過去的一年里，市場表現出了驚人的堅挺，很大程度上抵消了美國歷史上第三次彈劾總統帶來的負面影響。

而美伊之間日益緊張的地緣政治局勢給全球經濟造成的影響，卻遠非特朗普的彈劾案可比。

位于德國柏林的信用評級機構Scope ratings的主權評級主管丹尼斯·沈認為：“在特朗普彈劾案中，人們基本上認為，特朗普雖然受到了彈劾，但肯定不會被定罪，也不會提前下臺。但在伊朗問題上，出現不對稱風險和極端風險的可能性要大得多。”

伊朗問題與股市風險

市場觀察人士和軍事戰略家一樣，對“負面不對稱風險”——也就是潛在負面風險遠大于預期的正面效果的情況，是深惡痛絕的。無論是經濟學家還是分析師或者投資經理，他們的工作都是全面考慮各類風險場景，評估潛在的回報——或者像Scope Ratings那樣，評估一個國家的信用評級。所以在他們看來，彈劾總統是一個簡單的風險，但戰爭則是另一回事。

在過去的幾天里，這種不確定性給市場帶來的影響更是極為明顯。

自從上周特朗普下令炸死伊朗將軍卡西姆·蘇萊曼尼以來，全球市場不出所料地出現了資產拋售現象——一開始拋售幅度并不算大，然而令人擔憂的是，之后的拋售速度變得越來越快。

雖然美國市場在本周一下午的交易中普遍反彈，但一些反映市場波動性上升的常用指標（黃金價格飆升到近6年來的最高點，原油價格也出現飆升）和一些新興指標（比特幣價格飆升）也是不容忽視的。這說明投資者無疑對美國炸死蘇萊曼尼和隨后發生的一系列事件感到了不安——比如伊朗正式退出伊核協議、伊拉克投票驅逐美國軍隊，以及特朗普與伊朗最高領袖哈梅內伊之間不斷升級的口水戰等等。

在地緣政治方面，沒有人確定接下來會發生什么。很有可能雙方會發起一場針鋒相對的網絡戰，甚至是打一場小規模的代理人戰爭。全球的石油供給也有可能受到影響，原油價格有可能飆升到75美元，然后是80美元，甚至是90美元以上——當然，這一切也可能根本不會發生。

對市場來說，這種“有可能”本身就是一場災難，尤其是在短期內。蘇萊曼尼剛死沒幾天，市場的不確定性已經高到了天邊上。

本周一早盤開盤時，美國股市的波動性指數飆升了近10%，各大股指全線飄紅。而即便是在10年前金融危機最嚴重的時候，波動性指數都沒有達到如此令人擔憂的水平。很明顯，市場已經不再處于“定速巡航”的狀態了——雖然僅僅四天前，一切都還顯得那么井然有序。

有些拋售行為和波動性的上升并不令人意外。貝倫堡銀行的首席經濟學家霍爾格·施米丁指出：“由于去年市場的表現十分良好，當前的市場的下行風險自然是很高的，任何意外都有可能成為影響市場的大事件。而在情緒方面，我們也在尋找有沒有理由結束去年以來市場的亢奮情緒。在我這樣一名經濟學家看來，這件事真的會給全球經濟造成重大威脅嗎？我認為并不會。”

施米丁表示，中東最近的局勢雖然緊張，但無論目前的形勢看起來有多壞，都不足以讓他重新制訂對2020年的經濟展望。他仍然預計美國經濟今年將增長2.1%，低于2019年的2.3%。

不過作為一名經濟學家，他也正在關注一些令人感到擔憂的數據。首先是原油價格的大幅上漲可能將持續較長一段時間（目前，布倫特原油價格徘徊在70美元左右），這很有可能會打擊消費者的信心，加劇通貨膨脹，并影響消費者的樂觀情緒。

目前，這種情況似乎不太可能出現。但是，此事后續如果還有其他反轉——也就是所謂的“不對稱風險”，則很有可能在這樣一個大選年里，將特朗普推到絕境。

施米丁說：“汽油價格上漲，以及由此帶來的經濟上的打擊，絕對不會是你今年秋天想看到的景象。”（財富中文網）

譯者：樸成奎

When economists started drafting their 2020 outlooks a few weeks ago they had penciled in, as they do every year, the likely risks to the markets and the global economy. A meaningful trade deal between the U.S. and China not materializing was high on the list. Ballooning corporate debt was there too, as were China’s failure to right its economy and further delays to Brexit.

Conversely, the impeachment (let alone the removal from office) of President Trump was seen as a mere trifle for most 2020 forecasts. As for an airstrike taking out Iran’s top military commander, plunging the two arch-enemies into a precarious game of brinksmanship? Not even the most pessimistic prognosticator could see that one coming.

And yet here we are, not yet a week into the new year, and the global markets are facing a test unlike any they saw in 2019.

The markets were impressively resilient throughout the past year, most notably shrugging off the impeachment of a U.S. president for only the third time in the nation’s history.

Rising geopolitical tensions between the U.S. and Iran isn’t likely to be the same kind of ho-hum affair.

“With the impeachment proceedings, it was by and large mostly taken for granted that the president would be impeached and not be convicted, not be removed from office,” says Dennis Shen, a director in sovereign ratings for Berlin-based Scope Ratings, a credit ratings agency. “With Iran, there’s a much higher asymmetric, or tail, risk.”

Iran and the risk to the stock market

Marketplace observers, like military planners, hate the "negative asymmetric risks," those in which the potential downside far outweighs the desired upside. An economist, analyst or portfolio manager is paid to think through all kinds of risk scenarios to assess potential return, or, like Scope, credit worthiness. For them, an impeachment scenario is fairly straightforward. War is not.

This lack of clarity has played out at points in the markets over the past few days.

Since President Trump ordered the airstrike last week that took out Iranian General Qassem Soleimani global markets have, predictably, sold off—moderately at first, and then, more worryingly, at an increasing rate.

And while U.S. markets recovered broadly in afternoon trade on Monday, many of the usual indicators of rising market volatility (gold rallying to a six-year high and crude spiking) plus some new ones (the price of bitcoin soaring) are there. Together, they reveal that investors are undoubtedly unnerved by the Soleimani slaying and the events that’ve followed. Namely, that would include Iran’s official pullout of the nuclear deal, Iraq’s vote to expel U.S. troops, and the escalating war of words from Trump and the Ayatollah Ali Khamenei.

On the geopolitical front, nobody is sure what will happen next. Possibilities include a tit-for-tat cyber war. Or, maybe it’s a military skirmish fought by proxy militaries. Maybe there’s a disruption to oil supplies. Maybe crude spikes to $75, then $80, or even $90 or above. Then again, maybe not.

For markets, the what-ifs are nearly as bad as the real thing, particularly in the short term as we’re seeing. And, just a few days into the ordeal, the uncertainty is sky high.

On cue, the Vix, or so-called Volatility Index, spiked nearly 10% Monday morning as the markets opened in the U.S. with every major index in the red. Zoom back, and the Vix is not nearly at the worrying heights it reached during the worst of the Great Recession, a decade ago. But it’s clear: the markets are no longer on cruise control—no longer where they were just four days ago.

Some of the sell-off and ramp-up in volalitity is to be expected. “Markets at the moment are of course highly vulnerable because markets had such a good run last year, that anything unexpected is a major market event,” said Holger Schmieding, chief economist at Berenberg. “Sentiment-wise, we are looking for reasons to end the euphoria of last year. The question for me as an economist is that really something that adds up to a major threat to the global economy? And I think it does not.”

Schmieding says the latest tensions in the Middle East, no matter how bad they seem at the moment, are not enough to get him to rewrite his 2020 economic outlook. He still predicts U.S. economic growth at 2.1%, down from 2.3% in 2019.

But being an economist, he’s on the look out for worrying data points. Chief among them would be a big spike in the price of crude for an extended period—say, $90 a barrel for three months or more (Brent is hovering around $70 at the moment)—something that would hit consumers at the pump, goose inflation and sink consumer optimism.

At the moment, that scenario doesn't seem likely. But still it’s the kind of turn of events—"asymmetric" in other words—that could doom an incumbent president in an election year.

“Higher petrol prices, and an economy that takes a hit from that is not the backdrop you’d want to have this autumn,” Schmieding says.