Investors around the globe this week sent President Trump a clear message about his new tariff policy, announced triumphantly as a remaking of the economic order.

They don’t like it.

The S&P 500 fell 6 percent on Friday, bringing its losses for the week to 9.1 percent. Stocks hadn’t fallen this far this fast since the early days of the coronavirus pandemic — it was the steepest weekly decline since March 2020.

As then, the S&P 500 is quickly approaching bear market territory, a drop of 20 percent from the latest high and marks extreme pessimism among investors. By Friday, the index was down more than 17 percent from its February peak. The tech-heavy Nasdaq Composite and the Russell 2000 index of smaller companies, which are more sensitive to changes in the economic outlook, have both already fallen into a bear market. Around the world, stocks have tumbled.

But this meltdown wasn’t driven by the emergence of a new and deadly virus, or an unforeseen housing crisis like the one that wiped out stock values in 2007 and 2008 as it triggered the worst economic crisis since the Great Depression.

It was driven by a policy decision by the president.

“I hope that the message that the stock market is sending to the administration is being heard,” Ed Yardeni, a veteran market analyst, said in a television interview. “The market is giving a big thumbs down to this tariff policy.”

Analysts and market historians struggled to point to another time a president had inflicted so much damage on the financial markets. There are some recent parallels: An ill-timed budget proposal by Liz Truss, Britain’s prime minister in 2022, led to days of market chaos, and she had to resign within weeks.