The Shanghai Composite Index (SCI) on Thursday sank to its lowest level in three weeks as rumors of regulatory restrictions on financial companies’ equities investments sparked what one analyst described as "panic selling," Bloomberg reported. The SCI closed down 3.9% at 2,121.25 points, its lowest since February 5. The CSI 300 Index, which tracks both Shanghai- and Shenzhen-listed stocks, fell 5%, its biggest single-day decline since November 18. The China Insurance Regulatory Commission rushed to reassure investors that there was no truth to reports that it was going to lower insurers’ stock investments. It said insurers increased their equity holdings in January, contrary to claims that investments had been cut by US$10.1 billion. Anhui Conch, China’s biggest cement maker, and CITIC Securities were among the biggest losers, falling 6.9% and 5.8% respectively. Despite the decline, the SCI remains up 17% so far this year, the best among the 90 benchmarks globally tracked by Bloomberg.