Shenzhen Stock Exchange to cap stock weight at 15% in ChiNext index
The Shenzhen Stock Exchange will revise its ChiNext index compilation to gradually lower the single-stock weight cap to 15 per cent, aiming to reduce volatility amplification and concentration risk. The change takes effect on 14 December.
The Shenzhen Stock Exchange has announced a revision to the compilation methodology of the ChiNext index, which will gradually lower the upper limit of the weight of any single constituent stock to 15 per cent. The adjustment, intended to mitigate the amplification effect of volatility from heavily weighted individual stocks and reduce concentration risk, will take effect during the next regular index rebalancing on 14 December.
According to a notice on the exchange’s website, during each periodic rebalancing, if the actual weight of the largest constituent stock exceeds 14.5 per cent, the exchange will add 0.5 percentage points to that weight and then round up to determine the new single-stock weight cap. This cap will apply until the next rebalancing.
The exchange said that during the adjustment period, both the weight cap and the weight adjustment factor will only be lowered, never raised, until the actual weight of the largest constituent stock falls to no more than 14.5 per cent, thereby achieving the target of a 15 per cent weight cap.
The move follows a similar announcement by the Shanghai Stock Exchange in September, which said it would revise the compilation methodology of its Shanghai composite indices by introducing a rule that no single constituent stock may have a weight exceeding 15 per cent.
The Shenzhen exchange said the revision aims to improve the index's representativeness and reduce the risk of excessive concentration, which can distort the index's reflection of overall market performance.