Few firms of Uber’s stature have stumbled so badly out of the gate as a public company. Other well-known tech brands, from Facebook to Snap to Alibaba to Lyft, all rose on their initial trades. Since 2000, only 18 companies valued at more than $1 billion and listing on American exchanges had opened below their I.P.O. price. On average, tech stocks have jumped — or “popped,” in Wall Street parlance — 41 percent on their first day of trading over the past 24 years, according to Dealogic.

[Read more about why Uber’s dismal showing is a rare event on Wall Street.]

Uber raised $8.1 billion from its I.P.O., but the company and its bankers appeared to have misjudged how much investors would embrace the stock, which closed at $41.57. Last year, bankers said Uber could be valued at $120 billion upon its I.P.O., which would have made it the biggest American company ever to go public on an American stock exchange.

But that number declined in recent weeks amid questions about whether the deeply unprofitable company could make money. That was compounded by the performance of rival Lyft, which enjoyed a first-day surge when it went public in March but quickly fell below its I.P.O. price, and which posted a huge first-quarter loss this week.

Uber’s debut was also marred by a volatile stock market. On Friday, the S&P 500 index was on track for its fifth consecutive daily decline and its worst weekly performance of the year amid worsening trade tensions between the United States and China. But even as the index rallied to end the day higher, Uber’s stock continued to fall.