Three Chinese firms that run stock trading platforms, including one part-owned by Alibaba 's founder Jack Ma, were slapped with fines by regulators late Wednesday, as Beijing seeks to mitigate extreme bouts of volatility in its stock market.

Hangzhou Hang Seng Network Technology Services, Shanghai Mingchuang Software Technology (MECRT) and Zhejiang Hexin Tonghuashun Network Information were fined approximately 453 million yuan (Exchange:CNY=) ($71.2 million) in total, according to a press statement released by the China Securities Regulatory Commission (CSRC) on its Weibo account.

Hangzhou Hang Seng Network Technology Services is a subsidiary of Hundsun Technologies, which is partly owned by Ma's Zhejiang Finance Credit Network, according to Reuters. The financial investment company controlled by Ma invested $532 million last year to acquire a stake in Hundsun Technologies.

An additional 151 million yuan of "illegal gains" were confiscated by the securities regulator, while top executives of all three companies were dealt with warnings alongside penalties ranging from 50,000 to 300,000 yuan, the statement issued late Wednesday said.

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"According to our investigations, [the platforms provided by these three companies] allowed investors to conduct trading without providing real identities. By knowingly providing services to these unlicensed clients, these firms have earned illegal gains and created severe disorder in the securities market," CSRC said.

The announcement on Wednesday is the latest step taken by Chinese regulators to curb volatility following a sharp plunge in the country's stock market.

Earlier in the day, the China Financial Futures Exchange said it would step up its fight against excessive speculation in stock index futures trading, by raising the margin requirements for both hedging and non-hedging futures contracts starting from September 7.

Meanwhile, the government also said it would abandon the use of large-scale share purchases and will instead intensify efforts to find and punish those suspected of "destabilizing the market," the Financial Times reported on Sunday citing senior officials.

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According to mainland media outlet The China Daily, 197 people have been punished in a campaign by police targeting online rumors, with 165 accounts closed for violations. A journalist with financial magazine Caijing has since been detained by Chinese authorities, a report by Xinhua news agency on Sunday said, alongside two officials from the CSRC and eight managers from Citic Securities (Shanghai Stock Exchange: 30-SZ) for "illegal market activities."