Leading foreign brokerages and investors are re-examining the investment value of Chinese internet and technology companies through upgrading or buying related stocks recently after a sharp sell-off this year.

JPMorgan upgraded on Monday a slew of Chinese internet and tech companies including Alibaba Group, Tencent Holdings, NetEase Inc and Meituan to overweight, and JD, Bilibili and several other Chinese companies from underweight to neutral.

Overweight, underweight and neutral are performance indications of how analysts think the stock will do in the foreseeable future. An overweight, for instance, is mainly a recommendation to hold more of the stock than the relevant benchmark index.

Market sentiment was already boosted as the Hang Seng Index climbed 3.27 percent to 20602.52 on Tuesday, heading for the highest close since May 5. Alibaba rose more than 7 percent, while JD and Bilibili rose more than 7 percent and 6 percent, respectively, on the Hong Kong bourse.

The new optimism is in sharp contrast to a March report where the brokerage downgraded 28 Chinese internet stocks to neutral or underweight.

JPMorgan analysts led by Alex Yao explained in a report on Monday that the new classification came because the so-called significant uncertainties facing the sector should begin to abate on the back of recent regulatory announcements.

On April 29, the country called for efforts to promote the regulated and healthy development of the platform economy in a meeting of the Political Bureau of the Communist Party of China Central Committee, which has been widely seen by global industry insiders as China's sign of easing of regulations on the tech sector.

"We had originally forecast that these various uncertainties would continue for six to 12 months, with the earliest relief possible in the second half of the year," the analysts said.

"We expect early-cycle sectors such as digital entertainment, local service, and e-commerce to be the first batch of outperformers," they added.

JPMorgan's flagship fund in China increased its positions in JD in the first quarter while leading Wall Street asset management firms including Bridgewater Associates and Fidelity International already increased their holdings of Chinese internet technology stocks, including Tencent, Alibaba, Meituan, Pinduoduo and Baidu.

"The optimism is mainly because the stocks of leading Chinese internet and technology firms are now attractive for investors given their current low valuations," said Pan Helin, co-director of the Digital Economy and Financial Innovation Research Center at Zhejiang University's International Business School.

Pan said that many of these China-related stocks represent some of the best companies for the new economy and still have great growth potential in earnings and returns.

"Also in China, the platform economy has ushered in a new era of normalized supervision and has begun to develop with high-quality," he added.