According to a filing to the Shanghai Stock Exchange late on Sunday, two senior executives at Everbright Securities had resigned. The resignation of the securities firm's executives followed after China Securities Regulatory Commission (CSRC) uncovered evidence of insider trading and other irregularities against the company. Assistant President Yang Chizhong and Board Secretary Mei Jian handed in letters of resignation on Saturday, as detailed in the filing.

In a separate filing to the exchange, Everbright Securities confirmed it had received a notice from the CSRC detailing the heaviest penalties in the country's stock market history at CNY 523 million. The brokerage, however, stopped short of saying whether they would appeal to the regulator or not.

The punishments and resignations came after a glitch in Everbright's computer system caused an unintended placement of buy orders to the exchange on Aug. 16. The glitch led to a massive but short-lived jump in the Shanghai Composite Index. Everbright capitalized on the error by taking steps to curb losses in the erroneous trades. Investors who had followed the trades and were misled about the glitch, however, generated losses.

According to the CSRC, this constituted a deliberate violation of exchange rules. The regulator also claimed that some brokerage executives deliberately circulated information that misled investors.