Social networking site Facebook had a roller-coaster ride through its first day listed on a stock exchange, after one of the world's biggest-ever business "floats".
Facebook shares jumped by more than 10% within minutes of making their stock market debut in New York but later dropped back to just above their $38 initial price.
Later gains were wiped out too at the end of a volatile day's trade on the Nasdaq exchange, as the firm's debut was also delayed by a technical glitch, and the stock closed at $38.23.
The firm's founder Mark Zuckerberg opened Friday's trading on the exchange via a link from a celebration at the firm's headquarters in California.
About 82 million Facebook shares changed hands in the first 30 seconds of trading, the BBC reports. Overall, more than 566 million shares in the company changed hands, a record volume for US market debuts.
Nobody knows yet whether the eight-year-old internet firm founded in a student's bedroom will prove itself to be truly worth more than $US104 billion, even if it can claim a staggering 13% of the world's population as subscribers.
Most analysts had expected the shares to experience a first-day bounce.
"This starlet tripped on the red carpet. That's clear," said Max Wolff, senior analyst at Greencrest Capital.
He added that the only reason the shares did not fall below the offer price was because underwriters stepped in to buy the stock.
Questions over revenue
Facebook's $104 billion valuation means the social network site is worth about the same as internet shopping giant Amazon, and more than the value of stalwarts such as Disney.
The site is largely used for social updates, and although Facebook has said its use on mobile devices are the key to new profits, analysts question how much room there is for advertising on such platforms.
Car giant General Motors added to those doubts by saying on Tuesday that it would no longer pay to advertise on the site.
Facebook's profits are tiny in relation to its size - it makes about $US5 a year for each of its 900 million users - and its plans to increase profitability are unclear.
Other internet companies have had mixed experiences when they have started selling shares, the BBC reports.
Online games maker Zynga's shares fell 5% on their first day of trading in December 2011.
But shares in business networking site LinkedIn more than doubled on their debut in May last year and are still trading well above that level.
Groupon shares jumped 30% on their debut in November but have since fallen back.