Inc., the maker of China's leading Internet search engine, mesmerized Wall Street Friday as its stock more than quadrupled in its first day of trading, marking the biggest one-day gain of an initial public offering since the final days of the dot-com era.

The Beijing company's shares closed at $122.54 on the Nasdaq Stock Market, a 354 percent gain from its IPO price of $27.

The rapid run-up gave Baidu a market value of $4 billion -- a lofty appraisal of a 51/2-year-old company that only recently became profitable. Baidu earned $1.8 million on revenue of $13.6 million during the first half of this year.

The company's management expects much bigger things as more of China's vast population begins to surf the Internet. More than 100 million of China's residents currently surf the Web. Baidu has been able to pluck enough visitors from that audience to emerge as the world's sixth-most-trafficked Web site.

"I am very confident in the future of Internet search in China," Baidu Chairman Robin Li said Friday. "This is a very basic need for every consumer in China."

As the early search-engine leader in China's nascent Internet market, Baidu is inspiring comparisons to Google Inc. Like Google, Baidu -- traded under the ticker symbol BIDU -- so far has made most of its money from text-based ads that are tied to search requests and generate a commission whenever the commercial links are clicked on.

Drawn by Baidu's potential, Google even paid $5 million last year for 749,625 of the company's shares -- a stake worth $92 million Friday.

Google's early ownership interest has convinced some investors that the U.S. company will eventually buy Baidu for a lucrative price, although there has been nothing concrete to support that belief.

No IPO has climbed as high on the first day of trading since the shares of software maker Selectica Inc. soared 371 percent during their March 2000 debut, according to Selectica's shares closed unchanged Friday at $3.15.

Memories of Google's IPO may have provided Baidu with its biggest lift. Nearly a year ago, Google went public at $85 per share -- a price that many investors viewed as inflated but now looks like a bargain with the company's shares closing at $292.35 Friday.

Baidu has awarded stock options to its 700 employees in China, giving them a slice of the wealth created by the IPO.

"We are going to try not to pay attention to the stock [price]," Li said. "As long as we do our job, the stock should take care of itself."