From the China Business Services Blog, economist Andy Xie says:

"The Chinese stock market entered bubble territory when the Shanghai A-share index passed 2,500. A bubble has a natural life, driven by human psychology…Chinese investors usually associate a bubble burst with government intervention and think that a bubble could continue forever without government intervention. This is not true. A bubble can collapse under its own weight. The U.S. stock market did so in 1929 and Japan's in 1989. Hong Kong's market collapsed due to an external disturbance. The tech bubble in 2000 collapsed when overcapacity destroyed corporate earnings. You never know how a bubble will burst. But it always does."

To read more:

http://www.chinabusinessservices.com/blog/?p=494