Jamie Dimon and Sergio Ermotti starred in the roadshow promoting Postal Savings Bank of China Co's share sale. Yet the executives' participation in this year's biggest initial public offering also serves as a reminder that investing in Chinese banks isn't what it used to be.

When China's fifth-largest bank priced its $7.4 billion share sale last week, UBS and JPMorgan snared 5 percent paper gains on investments made nine months earlier. The shares will start trading in Hong Kong on Wednesday after being priced near the bottom of a marketed range.

Bank of America Corp and Goldman Sachs Group Inc more than doubled their money with China Construction Bank Corp and Industrial & Commercial Bank of China Ltd stakes respectively in 2005 and 2006 before those firms' shares started trading. History is failing to repeat itself as investors fret at the risks weighing down Chinese lenders.