Shares of Uber stalled on their first day of trading Friday, falling 7.6% to just under $42 amid mounting trade war tensions.

And, according to noted IPO watcher Jay Ritter of the University of Florida, on a dollar basis, investors who purchased the 180 million shares offered through the IPO at $45 per share collectively logged $618 million in paper losses Friday. That represents the worst dollar losses for a U.S. IPO going back through 1975, excluding foreign stock listing in the country via American Depository Shares.

In terms of the share price drop, Uber’s IPO ranks as the ninth worst first day performer of all time, according to DealLogic.

That puts further pressure on investors including Saudi Arabia’s sovereign wealth fund, who bought in at a time when shares were higher than $45.

The sell off came as President Donald Trump escalated the trade war with China, boosting tariffs on some $200 billion worth of goods from 10% to 25% Friday. Investors have also been somewhat jittery about Uber, after its rival, Lyft, also had a lackluster IPO. Shares of the latter firm are down 35% since their debut in April.

First day trading doesn’t determine a company’s future, however. (Remember Facebook’s flop?) And while IPOs are often priced to “pop” on the first day, critics of the practice argue that it leaves cash on the table—cash that investors were willing to pay, but the company ultimately did not take to grow its business.

Regardless, this probably is not the kind of history the transformative company hoped to make on its first day as a public company.

More must-read stories from Fortune:

—Why rideshare drivers are going on strike

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—The uncomfortable truth about going public with a money-losing business

—How the Kleiner Perkins empire fell

—From 2017: Silicon Valley and the Search for Meatless Meat

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