The Shanghai Composite Index sank 7.7 per cent to 3,116.35 at the close, its steepest drop since June 2008. Citic Securities Co and Haitong Securities Co, the nation's two biggest listed securities firms, fell by the 10 per cent daily limit after they were suspended from loaning money to new equity-trading clients and regulators said brokerages shouldn't lend to investors with assets below 500,000 yuan. About nine stocks dropped for each that rose on the Shanghai gauge, with more than 100 companies retreating by the maximum allowed.
"Regulators are concerned that shares have run too hard, too fast," said Hao Hong, a strategist at Bocom International Holdings Co in Hong Kong. "They want a measured increase in the stock market. After all, margin financing is one of the reasons for people to be bullish on brokerage stocks, and these stocks have run particularly hard."
The Shanghai measure advanced 2.8 per cent last week, a 10th week of gains that's the longest winning streak since May 2007, after credit growth expanded and speculation grew the central bank will cut reserve-requirement ratios.
Margin suspensions
An index of financial companies tumbled by a record on the CSI 300 Index, which tumbled 7.7 per cent. The Hang Seng China Enterprises Index of mainland shares traded in Hong Kong sank five per cent, while the Hang Seng Index fell 1.5 per cent. A gauge of volatility rose to a five-year high in Shanghai.
Citic Securities, Haitong Securities and Guotai Junan Securities Co were suspended from lending money and stocks to new clients for three months, the China Securities Regulatory Commission said on its microblog on January 16 after the market closed.
Record plunge
"China is trying to rein in over-bullishness in the stock market as moves have been exaggerated," Pauline Dan, Hong Kong-based head of Greater China equities at Pictet Asset Management Ltd, said by phone. "Investors will have to wait and see until this volatility settles. They don't have a fundamental reason to stay long since government policy is driving the market."
The amount of shares purchased on margin has surged more than tenfold in the past two years to a record 1.1 trillion yuan ($179 billion), or about 3.5 per cent of the nation's market capitalization. The Shanghai and Shenzhen exchanges expanded the number of stocks available for margin trading to 900 from 695 in September.
Minimum requirement
The CSI 300 financial index tumbled 9.6 per cent, the most according to Bloomberg data going back to July 2007. Ping An Insurance Group Co, China Minsheng Banking Corp and Bank of China Ltd all fell by the daily limit. Other large-cap stocks also slumped, with PetroChina Co falling 9.2 per cent and Agricultural Bank of China Ltd dropping 9.9 per cent.
Citic said in a stock filing today that it raised the minimum requirement for opening margin lending accounts to 500,000 yuan from 300,000 yuan. In a margin trade, investors use their own money for just a portion of their stock purchase, borrowing the rest from a broker. The loans are backed by the investors' equity holdings, meaning that they may be forced to sell when prices fall to repay their debt. Huatai Securities advertised margin lending rates of 8.6 per cent on its website on Monday.
Small-cap stocks are among the favorites of margin traders, Yu Liang, an analyst at Deutsche Bank AG, wrote in a January 5 report. Beijing-based Sumavision Technologies Co, which makes and sells digital TV software and hardware products, has $238 million of shares bought on margin, or 17 per cent of its market capitalization, according to the report. Xuzhou Combustion Control Technology Co has $112 million or 23 per cent of the stock's market value.
Other companies include Shanghai Duolun Industry Co and Zhejiang Jianfang Group Co, the Deutsche report shows.
Economic figures
China is scheduled to release data tomorrow that's forecast to show the economy grew in the fourth quarter at the slowest quarterly pace since 2009.
The nation's gross domestic product growth probably weakened to 7.2 per cent in the October-to-December period, according to the median estimate in a Bloomberg survey. The economy grew 7.3 per cent a quarter earlier. Economic expansion may reach 7.3 per cent this year, the Xinhua News Agency reported over the weekend, citing central bank adviser Song Guoqing.
China Vanke Co and Poly Real Estate Group Co both slid 10 per cent. The nation's new-home prices fell in 65 of the 70 cities monitored and were unchanged in four last month, the National Bureau of Statistics said in a statement on Sunday.
That compares with declines in 67 cities in November.
The Shanghai Composite is the best performer among 93 global indexes tracked by Bloomberg over the past year. The index was valued at 11.9 times 12-month projected earnings last week, the highest level since April 2011, according to data compiled by Bloomberg.