China's ChiNext Index is surging to an 11-year high, but rising concentration risk is emerging as a key concern. Contemporary Amperex Technology Co. and Zhongji Innolight Co. along with five other heavyweight stocks now account for nearly half of the index's weighting, according to Bloomberg data.

This concentration level is striking when compared to broader benchmarks. The top seven stocks in the CSI 300 Index represent just 20% of that gauge's weighting, highlighting how the tech-heavy ChiNext has become increasingly dominated by a small group of performers. CATL alone represents roughly a fifth of the ChiNext's composition.

Recent earnings have fueled this concentration. CATL reported stronger-than-expected results this month, while Zhongji Innolight announced a 262% jump in earnings. As these mega-cap tech stocks continue to outperform, investors are watching closely to see whether this concentration trend will persist or whether broader market participation will emerge.