On the afternoon of October 9th, a number of investors received SMS alerts from East Money Securities. The messages indicated that, commencing from that very day, the margin trading discount rates for SMIC and BIWIN Storage securities held in credit accounts had been revised down to 0.00. Previously, SMIC's rate stood at 0.70, while BIWIN Storage's was at 0.50.

East Money Securities' customer service team verified this modification. They clarified that, in line with exchange regulations, whenever an individual stock's static price-to-earnings ratio (P/E ratio) surpasses 300 times or turns negative, its margin trading discount rate is automatically set to zero. Notably, both SMIC and BIWIN Storage currently exhibit static P/E ratios well above the 300-times threshold.

These regulatory stipulations have been enforced since 2016, with the fundamental guidelines remaining intact to the present day. While there were some stock-specific adjustments made in July 2025, the core tenets of the regulation have stayed consistent. The primary objective behind these measures is to bolster risk management and safeguard the seamless functioning of the margin trading sector.