Chinese regulators fined and reprimanded a construction company on Monday for violating stock market disclosure rules following weekend warnings that efforts to clamp down on insider trading and other manipulation would be “strengthened”.

The China Securities Regulatory Commission (CSRC) said it had fined Zhejiang Hangxiao Steel Structure Rmb400,000 ($52,000) over the way it disclosed a contract in Angola that led to a fivefold increase in its share price. Five senior managers were also fined.