The market value of China's A-share market accumulatively shrank by 903.2 billion yuan ($139.6 billion) in the first half of this year, China Securities Journal reported Wednesday.

The Small- and Medium- Enterprises (SME) and Growth Enterprise Market (GEM) boards on the Shenzhen Stock Exchange encountered a sharp slide, shrinking by 728.6 billion yuan and accounting for 80.68 percent of the total losses, data showed.

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Despite the bear performance of the SME and GEM boards, the main board stocks told a different story. The best performing nine stocks so far this year are all listed on the main boards, becoming the bull force in the A-share market, according to the newspaper.

Data also showed that when the trading closed on June 28, the trailing twelve months price-to-earnings ratio (TTM P/E) of the Shanghai Shenzhen CSI 300 Index decreased to 13.56, compared to 14.52 at the end of last year. The ratio for the SME board dropped from 45.75 last year to the current 36.48, while for the GEM board the ratio retreated from 65.92 to 43.88.

An unnamed analyst said that with expectations of more tightening measures, the under-valued main board stocks will rise gradually. But as for the SME and GEM boards, it is inevitable to face big losses in the market value under the guidance of "lowering the valuation".

In addition, the stocks prices of many industries including electronic devices, information services, bio-medicine and tourism fell sharply with the downward trend of the total market, the newspaper reported.