Chinese stock ETFs are rising even as mainland markets are closed for holidays

That's because these funds mostly invest in Chinese stocks traded on the Hong Kong Stock Exchange or in listed U.S. companies that are headquartered or incorporated in China. Markets in mainland China, including the Shanghai and Shenzhen exchanges, will remain closed until October 8.

“I am bullish on Chinese stocks; this time is different,” Scott Rubner, tactical specialist at Goldman Sachs, said in a note. “I have never seen such high daily demand for Chinese stocks: I don’t even think we have gone back to benchmark index weights.”

Chinese stocks reversed last week after Beijing launched a flurry of stimulus measures to deal with a deep economic downturn, including interest rate cuts and a reduction in the amount of cash banks must hold on hand.

The government's promise of strong economic stimulus sparked renewed optimism in Chinese stocks, which had come under pressure in recent years due to the sluggish economy and strict regulatory measures. David Tepper, founder of hedge fund Appaloosa Management, told CNBC last week that he buys “anything” related to China because of government support.

JD.com rose 5% on Wednesday, rising for the fifth straight day. Another e-commerce namer PDD gained 4.8% after an 8% rally the previous day.