Facebook saw a roller-coaster market debut Friday after an early surge faded, and then buyers stepped in give the stock fresh momentum.
The shares, priced at $38 on Thursday in the largest-ever initial public offering (IPO) for a technology company, jumped 12 percent to $42.55 in the opening Nasdaq trades but within minutes fell back to the offering price.
At 1700 GMT, the shares were back up 8.3 percent at $41.15.
Gerard Hoberg, an economist at the University of Maryland said there was enthusiasm from some buyers but skepticism from professionals.
"What I think is going on is you have a lot of bullishness from retail investors, people who use FB, and there's a lot of those investors creating a lot of buying pressure," he said.
"But professionals who were looking at the numbers behind Facebook had a lot more doubts, and that is cooling the issue quite a bit."
Hoberg said the market introduction "is not a disaster by any stretch, and you also could say that the Facebook owners are quite pleased because they didn't leave a lot of money on the table. But it will not be a pleasant taste in people's mouths if Facebook falls below $38 anytime in the near future."
A report on the Business Insider financial blog said the price did not fall below $38 because of a large number of standing orders at the offering price. The Wall Street Journal said the underwriting investment banks also stepped in to support the price.
Lou Kerner of the Social Internet Fund said the market action suggests the IPO was correctly priced.
"The bankers appear in the first few minutes to have done a pretty good job," he said.
"The company raised a ton of money, lots of early investors, employees, and founders were able to monetize shares, and it's trading up a little, so the new investors did OK."
James Hughes, chief market analyst at London's Alpari said "the real value of Facebook is not likely to be known until the hype of the IPO has died away and investor have been able to digest how the company is going evolve to be the money-making machine many expect it to be."
Elsewhere in the tech world, shares of online social game maker Zynga plunged 13.3 percent and triggered a trading halt .
Shares in Zynga, which makes popular games used on Facebook and other platforms, were halted at $7.17, near where they started at the beginning of the week before a strong climb ahead of Facebook's market debut.