The stampede for the exits resonated as recognition that a vast range of policies framing global commerce â from trade to immigration to defense to climate change â were now subject to a potentially radical refashioning.
It is said frequently that what markets crave more than anything is certainty. The globe suddenly seems in dire shortage of that.
The stunning June vote in Britain to abandon the European Union effectively redrew the regional map governing trade, risking a rupture within a marketplace encompassing 500 million relatively affluent people. But a Trump presidency presented the possibility that the whole atlas for international commerce had been torn to bits.
During the campaign, he vowed to renegotiate the North American Free Trade Agreement between Mexico, Canada and the United States. He repeatedly promised to slap punitive tariffs on imports from China, raising the prospect of a trade war between the worldâs two largest economies.
Mr. Trump at one point threatened to renegotiate the terms of American debt, effectively raising the prospect of a sovereign default in the epicenter of the global financial system and a loss of confidence in the reliability of the American currency. If faith in the basic sanctity of the dollar cannot be taken as a given, then nearly every crevice of finance is subject to some additional layer of risk â from mortgages to corporate bonds to government debt.
More broadly, Mr. Trump vowed to radically alter a host of agreements made between the American government and significant actors on the global stage, from the Paris accord setting out targets to reduce the pollutants contributing to climate change, to the deal aimed at constraining Iranâs nuclear aspirations. He promised to escalate the battle against the Islamic State, intensifying bombing in Iraq and Syria. He vowed to build a wall along the Mexican border.
Taken as a whole, markets digested the looming Trump presidency as a signal that the knowns are now vastly outnumbered by the unknowns â a clear signal to pull their money to the sidelines.
âThis is a negative shock for markets,â said Ricardo Reis, an economist at the London School of Economics. âFor sure, this is a huge increase in uncertainty. And for the most part what certainty is available seems bad. Like the Brexit vote, this raises the likelihood that trade deals will be repudiated and borders will be closed.â
In recent weeks, markets around the world had largely assumed the election would be won by Hillary Clinton, a known quantity with a track record in public life going back more than a quarter century.
But as returns emerged Tuesday evening, raising the possibility that two previously unimaginable words â âPresident Trumpâ â were on the verge of becoming official nomenclature, markets in Tokyo, Hong Kong, Australia and the rest of Asia dropped precipitously, shedding as much as 6 percent of their value by early afternoon.
As trading commenced in Europe, stock markets in Germany, Spain and Italy were all down more than 3 percent. London shares opened down some 2 percent, but then recovered somewhat.
Stock market futures indicated an almost-certain sell-off once Wall Street awoke. Futures on the Dow Jones industrial average dropped more than 4 percent, and the broader Standard & Poorâs 500-stock index plunged by about 5 percent, though both gained back some ground after Mr. Trumpâs victory speech.
As currency markets fluctuated, they appeared to be functioning as barometers of national prospects in the wildly unpredictable new era unfolding.