The market value of China's listed stocks tumbled by 7 percent in the past week with share prices suffering several huge blows in the past five trading days.

The value of Shanghai stock market shrank to 8.07 trillion yuan on Friday, 7.2 percent lower than that on the previous Friday of Jan. 26. The value of smaller Shenzhen bourse dropped 6.25 percent to 2.11 trillion yuan from a week earlier.

The key Shanghai Composite Index fell 4.03 percent to 2,673.21 points on Friday as investors took away profits from blue chip shares, fearing the shares are over-priced after strong rises over the past months.

Previously, the index tumbled 4.92 percent to close at 2,786.34 points on Wednesday, the biggest one-day losses in the past seven months.

While the Shanghai and Shenzhen stock markets were very bullish in the past year, some experts warned that an investment bubble was developing.

However, Wang Xingjun, an analyst with the Donghai Securities, said the declines in the past week were normal following a long bullish period and investors should not be too pessimistic.

Editor: Yan