China's stock markets reopen tomorrow after a weeklong break. Investors — and social media — are buzzing.

• China's stock investors and watchers are discussing the markets before they reopen.
• China released a stimulus blitz a week before the National Day break, sending downtrodden markets on a tear.
• Mainland China's markets have been closed for a week.

China's investors are looking forward to some stock market action after the country's weeklong National Day break.

Beijing released a stimulus blitz on September 24, sending the markets on a hot run.

Mainland China's benchmark CSI 300 Index closed 17% higher year-to-date on September 31 before the weeklong break — a stark contrast to its meltdown and lackluster performance for much of the year. Hong Kong's Hang Seng Index closed 1.6% higher on Monday. It's up about 35% year-to-date.

On Monday, a day ahead of the mainland's markets reopening, China's version of Twitter, Weibo, was abuzz with discussions about what the markets may hold.

China's domestic stock markets are dominated by retail traders, who number over 200 million and account for about 70% of trading volume.

Trending topics on Weibo included #Hong Kong stocks, #How long this bull market can run, and #How A-shares will perform after the holiday. A-shares are stocks of Chinese companies listed on the Shanghai and Shenzhen stock exchanges.

"I hope the rally can hold for a bit longer, so that I can at least get my initial investment back," wrote one Weibo user. The CSI 300 index was down 45% from a 2021 peak until the pivotal announcement in late September.

There was also a trending hashtag discussing those who fear they will not be able to buy A-shares on Tuesday. Before the weeklong break, some brokers and traders reported delays on the Shanghai Stock Exchange as systems were so overwhelmed by enthusiastic investors and market watchers.

Despite the market rally, skeptics about China's economic outlook and markets abound.

"I don't feel reassured now that the topic is trending," said a Weibo user in a thread discussing the likely duration of the bull market. The thread garnered nearly 700 likes in half an hour.

Given the extent to which China's stocks have sold down before Beijing's stimulus announcement, there may be more upside to come.

Goldman Sachs, for one, has upgraded China's stocks to overweight and is forecasting another 15% to 20% upside to Chinese shares.

Beijing's "coordinated forceful policy announcements" amid "an oversold, undervalued, and under-positioned market backdrop" are key factors in their reasoning, the bank's analysts wrote in a note published on Saturday.

There could also be earnings growth potential for companies should the economy respond positively to Beijing's coordinated stimulus, they wrote.

"Together, these announcements constitute a more substantial quantum of policy stimulus that contrasts with the sporadic and modest easing measures over the past few years," they wrote, even as they warned that China's macroeconomic challenges remain serious.

China's stimulus measures include interest rate cuts and 800 billion yuan, or about $114 billion, to support the domestic stock markets. The country's top leadership has also pledged more stimulus is on the way. The world's second-largest economy is facing multiple challenges including a property crisis, deflation, and high youth unemployment.