China's stock market boom has given birth to a peculiar "derivative market," involving the trading of investors' stock-trading account information, yesterday's Shenzhen Evening News reported.

The information of an individual account is being sold for 0.08 yuan online while for 5,000 yuan, the information of all the stockholders in Shenzhen who opened their trading accounts by November can be bought. A man in Jiangxi Province sold information about a shareholder in Shenzhen for 0.18 yuan, saying the price was higher as all the Shenzhen shareholders he covered were "quality clients."

The story said the information was used by stock consulting companies or investment firms, which would call or send text messages to target investors using the information they purchased.

Investigations conducted by the newspaper found sellers of the information scattered across the country. They all had their own sources to obtain the information. Some obtained the information from colleagues and friends, while others obtained it from investment consultancies, securities companies, listed companies and even Web site operators.

An advertisement which appeared recently on a shopping Web site reads: "We've just obtained the latest detailed information about 2.2 million shareholders in China (highly confidential) from a securities company. The information includes stockholders' names, sex, addresses, the amounts of money they have invested, post code and telephone numbers. Welcome to order."

When contacted by a Shenzhen Evening News reporter, a man based in Shenzhen said he could only "negotiate" with his clients online. He asked the reporter to send the money to a designated bank account and promised immediate delivery of the information purchased through QQ, a popular free instant messaging service platform. "I've been in this sector for quite some time. Credibility is my priority," the seller is reported to have said.

The punishment for leaking clients' information is severe, said a representative of a Shenzhen-based securities company surnamed Du. The manager of another company, who was not identified, said no honest brokers would sell their clients' information to others. "Giving away the information, a valuable resource, which one took great pains to collect, is one of the most foolish things I can imagine," the manager said.

Legal experts say China has not drawn up any regulation on the protection of information related to personal stock trading accounts. However, they say anyone who trades in stockholders' information will be punished according to law as it constitutes bleaching others' privacy for profit.