The dramatic sell-off in China's main stock market has continued despite regulators desperate efforts to try to stem the losses.
The Shanghai Composite index plunged 8% on opening, taking the drop in share values to 30% since 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.
"Of course, this is tongue in cheek, but when we see around 90% of the market suspended or falling by their daily limit (while further measures have been taken to limit the influence seemingly exerted by futures traders) you know things are becoming less rational," he said.