As Hillary Clinton had what most polls found to be a convincing victory over Donald Trump in the first presidential debate, financial markets cheered in the same way they might respond to a particularly good piece of economic news.

During the debate, and in the hours afterward, financial instruments that bet on the future performance of US stocks rose, and ones betting on future market volatility fell. Oil prices jumped up — as they do when traders expect stronger economic growth in the future — and gold prices went down.

The moves were notable in large part because markets were cheering a Democrat, according to a new paper by economists Justin Wolfers and Eric Zitzewitz.

"In almost every case back to 1880, equity markets have risen on the news that Republicans win elections and fallen when Democrats win," the pair wrote. "The 'Trump discount' is an historic anomaly," they later conclude.

In fact, judging by trades made as Clinton enjoyed her win, "market participants believe that the S&P 500 will be worth 12% more under a President Clinton than Trump," they wrote.

It wasn't just in the US where Clinton's debate win was celebrated in real time.

British stock prices increased, and the value of the Mexican peso rose against the US dollar. Outside of Mexico, the countries whose markets and currencies were most affected tended to be ones with substantial US trade agreements.

South Korea's stock market rose "about twice as much" as markets in the US, UK, and other Asian countries, while the currencies of Canada, New Zealand, Australia, and South Korea jumped up as well.

The global breadth of market responses suggests that in the eyes of investors, a Trump presidency "is not seen as uniquely harmful to the United States, but rather is a broad global threat that impacts each of the equity markets we have studied."