China's stock markets have lost $6.3 trillion since 2021. This year's not looking better.

• China and Hong Kong stocks have lost about $6.3 trillion in market value since 2021, per Bloomberg data.
• The markets started 2024 in the red and are extending declines.

China stocks have been having it really bad amid a years-long market slump.

The rout is so bad that China and Hong Kong stocks have lost about $6.3 trillion in market value since hitting a peak in 2021, according to Bloomberg data published on Friday.

It's gotten worse since then.

Hong Kong's Hang Seng Index was down 2.6% at 2:27 p.m. local time on Monday after falling 12% this year to date. Meanwhile, the CSI 300 — which tracks 300 Shanghai and Shenzhen-listed stocks with the largest market capitalizations — is 1.13% lower after falling down about 5% so far this year.

Both markets started 2024 in the red. So much money has been lost that the market cap of all companies listed on the Tokyo Stock Exchange overtook the Shanghai Stock Exchange on Thursday for the first time since July 2020. The Japanese stock market rallied in 2023 after decades of unremarkable performance.

Still, some investors may be tempted by the market meltdown in the world's second-largest economy.

Almost one-third of 417 respondents to Bloomberg's weekly Markets Live Pulse survey earlier this month said they planned to invest more in Chinese stocks over the next 12 months.

But China's economy continues to face both short and longer-term challenges.

China's economy is struggling to recover post-pandemic. It's facing significant headwinds from both a property crisis and a demographics crisis amid a record-low birthrate. Its population contracted for the second straight year in 2023.

China's economy is expected to continue facing challenges after posting GDP growth of 5.2% in 2023 from a year ago, which the Economist Intelligence Unit, or EIU, graded as a "pass."

"While the economy did beat the official target, it could have scored a higher grade through a more forceful response to the property meltdown and greater commitment to the private sector," Tianchen Xu, a senior economist at the EIU, wrote in a note on Wednesday. Beijing had set its official growth target for 2023 at around 5%.