The 28 stocks on the ChiNext board in the southern boomtown of Shenzhen repeatedly tripped circuit-breakers in place to curb rampant speculation as keen buyers ignored warnings from regulators to trade in a “rational” way.

After a massive debut surge for all shares on October 30, with some soaring as much as 210 percent amid feverish buying, subsequent sessions saw stocks see-sawing up and down by the 10 percent limit in place on all Chinese bourses.

“I think it was crazy—the rise was ridiculously high,” said Peter Lai, a director of DBS Vickers in Hong Kong. “Chinese investors are not very rational.”

Yan Li, a Beijing-based analyst at Southwest Securities, said the casino-style trading “shows that investors lack an understanding of the risks”.

“Traditionally Chinese investors tend to chase after new stocks and such a trend will continue. I think the ChiNext board is very likely to see big fluctuations in the future,” Yan said.

Ahead of the start of ChiNext trade, the chairman of the China Securities Regulatory Commission, Shang Fulin, cautioned investors by saying start-up stocks have potential for strong growth—but also unstable financial results.

The long-awaited board is expected to give small and medium-sized companies access to financing and encourage private equity firms and venture capitalists to back start-ups, in the tradition of New York’s Nasdaq.

The first 28 companies to list on the board, ranging from movie producers to medical equipment makers, raised about 16 billion yuan (2.3 billion dollars) in their initial public offerings—more than double initial forecasts.

Market observers had been worried that ChiNext would draw funds away from the main boards and depress share prices.

But so far, the second board appears to have had little impact on main board trading, with China’s benchmark Shanghai Composite Index finishing at its highest closing level in nearly three months on Friday.

Analysts, warning of the risks of excessive speculation and overinflated stock prices on the new board, pointed to the price-to-earnings ratio of some companies, which exceeded 100 -- compared with about 30 on the main board.

“There are good companies on the board but they are too expensive at the moment,” La Bo, a Shenzhen-based analyst at Great Wall Securities, told AFP.

“The overall valuation of the board will come down eventually.”

For DBS’ Lai, a correction in share prices is “unavoidable”.

“Many domestic investors do not understand ChiNext companies’ financial figures and their business prospects. It’s more about speculation,” he said.

Hundreds of companies are reportedly lining up to list on ChiNext. The regulatory commission has already approved the draft initial public offering prospectuses of Zhejiang Hexin Flush Information Network and Wuxi Boton Belt.

“These are very early days but the basic direction, I think, is very sound,” said Ardo Hansson, lead economist at the World Bank in Beijing.

“It is a welcome addition to the different instruments in capital markets... but people need to know what they are getting into.”