
The Shanghai Composite Index shed 4.54%, or 158.45 points, to 3,331.33, and the Shenzhen Composite Index on China’s second exchange, dropped 4.31%, or 90.51 points, to 2,008.26.
Both bourses saw big gains the day before but were well off their initial highs.
The Hang Seng Index gained 1.74%, or 363.25 points, to 21,290.04, having tanked more than 9% Tuesday, its biggest loss since the 2008 global financial crisis.
Equities in the mainland and Hong Kong rocketed after China last month began announcing measures aimed at boosting the world’s number two economy, piling on more than 20% each.
However, a much-anticipated news conference in Beijing on Tuesday – after the Golden Week break – left traders disappointed as officials refused to unveil more stimulus and provided scant detail on the measures already pledged.