China's regulators are taking fresh steps to try to quell volatility in the country's financial markets.
Investors holding stakes of more than 5% are not allowed to sell shares in the next six months.
The new rule from the country's securities regulator is intended to relieve pressure on the stock market.
Despite efforts to stem the losses, the dramatic sell-off in China's main stock market continued on Wednesday, with the Shanghai Composite plunging 6.8%.
That took share values nearly 30% below their June peak.
On Wednesday, another 500 listed firms said they would stop trading their shares in an effort to insulate themselves from the meltdown.
Around 1,300 firms have halted trading, almost half of China's main shares.
IG chief market strategist Chris Weston dubbed the sell-off "Black Wednesday".
"For the first time, The China Insurance Regulatory Commission (CIRC) has admitted there is genuine 'panic selling' underway.
"When we see around 90% of the market suspended or falling by their daily limit you know things are becoming less rational," he said.
【参考译文】
为了稳定金融市场波动，中国有关部门制定了新的政策。
在未来半年内，持股超过5%的投资者不能出售所持股份。
这条由中国证监会颁布的政策意在缓解证券市场的压力。
虽然政府努力止损，但周三中国主要证券市场的大规模抛售仍在继续，上证指数下跌6.8%。
这让市值和6月高点相比下降了近30%。
周三，又有500家上市公司表示希望通过停牌来避开股价大跌。
目前已有1300家上市公司暂停交易，几乎占中国主要证券的一半。
IG集团的首席市场分析师克里斯·威士顿把此次抛售称为“黑色星期三”。
“中国保险监督管理委员会首次承认确实存在恐慌性抛盘。”
他表示：“当我们发现约市场上90%的证券都停牌或跌停，你知道事情正在变得不那么理智了。”
