The mainland's top securities regulator has met key market players and industry associations to warn them against non-compliance as the authorities start to round up those responsible for the stock market slump. China Securities Regulatory Commission (CSRC) chairman Xiao Gang summoned senior officials from 19 stock and futures exchanges, clearing houses and government-controlled industry associations directly under the authority in a recent meeting, ordering them to step up discipline and supervision, CSRC spokesman Zhang Xiaojun said yesterday. We must act immediately to subdue [China’s rogue institutions] SECURITIES DAILY COMMENTARY Zhang said 22 cases involving market manipulation, insider trading and spreading market rumours had been handed to police for further investigation. Many of the suspects were securities industry staff. Xiao's warnings reflect the mainland authorities' concerted effort to nab unscrupulous securities industry officials and fund managers amid a boom-to-bust cycle on the A-share market that has occurred despite Beijing's 1trillion yuan (HK$1.2 trillion) rescue funds meant to put a floor under the plummeting stocks. On Tuesday evening, police took away 11 people - eight Citic Securities managers, two CSRC officials and a Caijing journalist - to assist with investigations into market irregularities. The detention of the 11, three of whom are Citic executive committee members, was interpreted as a prelude to a wider crackdown on unethical brokerage staff after the latest market turmoil since last Thursday. The mainland market slump was also blamed for this week's "Black Monday", when global stock markets dived across the board. "All signs show the top state leaders are increasingly concerned about the ailing market," said a source with knowledge of CSRC's views. "An intensified crackdown is taking shape and the issue is going to be very serious." CSRC is also investigating other big brokerages Haitong Securities, GF Securities, Huatai Securities and Founder Securities. DON'T MISS: Insight and Opinion - Market rout will strengthen China's resolve to implement long awaited reform Also on Tuesday, the official Securities Daily published a commentary accusing some "core domestic brokerages" of colluding with foreign institutions to profit from the rescue funds. A source said the commentary came under "upper-level state leaders' directives" and that he believed it reflected President Xi Jinping's view point. "If our own institutions combine efforts with 'outsiders' to take advantage of the loopholes … it will … undermine national financial security," the commentary said. "We must act immediately to subdue them." The benchmark Shanghai Composite Index slumped more than 30 per cent between mid-June and early July, prompting Beijing to pump an estimated 1trillion yuan into boosting the falling shares. But the stocks continued their downward dive last week, knocking down the main gauge by 22 per cent in a four-day losing streak. On Tuesday, the indicator closed at 2,964.97 - 19.6per cent off the July 3 close when the regulator decided to pile fresh funds into the market. Yesterday, Zhang also said that starting on Monday, margin requirements for non-hedging futures contracts would rise to 30 per cent of contract values, up from 20 per cent.