Can anyone say "irrational exuberance"?

Shares in Baidu.com - "China's Google" - shot up more than 250 per cent in New York yesterday, in one of the most spectacular stock market debuts since the height of the dotcom mania of the late 1990s.

At the initial public offering price, Baidu's American depositary receipts were offered at 540 times historical earnings. Google, which owns a 2.6 per cent stake in Baidu, trades at about 74 times earnings.

But by midsession in New York yesterday, the stock was up 255.3 per cent at $95.94, slightly below intra-day highs.

The Chinese company made about $5.2m (£2.9m) in revenues in the first quarter of this year and $13.4m during all of last year, according to regulatory filings.

Baidu's Google-glow enchanted investors, whose enthusiasm was not dampened in the slightest by an IPR infringement suit brought against the Chinese search engine by the producers of Zhang Yimou's film House of Flying Daggers, reported by Bloomberg just days before the IPO.

Not everyone is impressed. CNN.com published an article yesterday that included the following quotes:

"People are buying shares in Baidu because of Google," said Tat Au Yeung, managing director of Apex Capital Management in Hong Kong. "But the pricing looks expensive."

But even analysts who expected a strong market debut were stunned on Friday.

"It's just been amazing. It could be over-enthusiasm, it could be the way Google charted, but there is obviously a lot of speculative buyers who think this could be an Asian Google," said Sal Morreale, who tracks IPOs for Cantor Fitzgerald. "Google was the last debut to come out so strong. It really is reminiscent of the go-go years of the late 1990s."

The go-go years were good while they lasted. But they didn't last all that long.