The ChiNext Index, China's NASDAQ-style board of growth enterprises, surged 3.62 percent to close at 1,742.19 points Thursday, the largest daily increase in a year.

Trading volume on the board stood at 88.18 billion yuan (13.1 billion U.S. dollars), also the highest in a year.

The index was down 0.15 percent at opening and hovered near the previous day's closing price in the first hour of trading before shooting upward at about 10:30 a.m.

The surge was partly due to reports about the index's valuation at a relatively reasonable level after plunges earlier this month.

Sharp plunges were seen between July 11 and 17, dragging the index down to its lowest level in more than two years. Later, it rebounded moderately ahead of Thursday's surge.

Bloomberg said in a Monday report that the valuation of the ChiNext was the closest it had ever been to that of NASDAQ, as the index's valuation based on reported earnings was 36.2, compared with 34.3 for NASDAQ.

A total of 27 companies on the board surged by the daily limit of 10 percent.

The benchmark Shanghai Composite Index edged up 0.06 percent to close at 3,249.78 points. The Shenzhen Component Index closed 0.95 percent higher at 10,395.19.