China's mainland was home to 2.8 million millionaires in terms of US dollar at the end of last year, a 4 percent increase on the year before but a slower growth due in part to curbs in the property market.[Hong Kong company registration]

The millionaires have an average age of 38, and 70 percent are men. Real estate and stocks remained their top-two preferred investments, the Industrial Bank and the Hurun Research Institute said in a joint report Monday.

Another 100,000 people joined the ranks of high-net worth individuals with assets worth more than 6 million yuan (US$969,000).

Meanwhile, the growth in the number of people with assets worth more than 100 million yuan was the weakest in four years with a 2 percent increase to 64,500 last year, mainly due to the housing curbs and stock market performance.

"When there was a downturn in the stock and property markets, Chinese wealthy people showed significant enthusiasm in alternative investments," Rupert Hoogewerf, chairman and chief researcher of the Hurun Report, said in Shanghai yesterday.

Alternative investments, including buying art, jewelry, wine, watches and clocks, became the third-most popular investment for mainland millionaires following real estate and equities. Most of the millionaires had shown an interest in this investment category since the financial crisis of 2008, according to the report.

[Set Up Company Hong Kong]"Alternative investments have only emerged on the mainland for four to five years. It's a very short period of time when compared to the situation in overseas markets," Hoogewerf said.

China became the world's biggest art auction market in 2010, followed by the United States.

In the year that followed, China accounted for 42 percent of the global value of art auctions, up sharply from 0.5 percent in 2002, and ahead of the 24 percent seen in the US.

However, some alternative investments have yet to make their mark on the mainland, the report said, citing classic cars as an example.

It also warned that there were risks involved with alternative investments, which included weak liquidity, high trading fees, [Hong Kong Company Formation]a non-standardized market, lack of regulatory institutions and the need to be informed about the item invested in.

Most wealthy individuals saw an annual return above 10 percent from alternative financial investments such as derivatives, according to the report.