Zhao Zhanling, a lawyer at Beijing Yunjia Law Firm, said data-related investigations may be conducted regularly in future as the country pays greater attention to cybersecurity. Companies should no longer just talk about data security, but take action in their daily corporate operations, Zhao added.

Xiang Ligang, director-general of the Information Consumption Alliance, a technology industry association, said: "These moves send a clear signal that data security will come under increased scrutiny as China places its sprawling digital economy in an improved legal framework to pursue high-quality development."

Rory Green, China economist at investment research provider TS Lombard, wrote in a research note: "The battle for data sovereignty is beginning … It is increasingly clear that governments around the world have recognized the importance of data and the need to regulate the utility-like private firms that control its production and flow."

Experts said that in an increasingly stricter regulatory environment, technology companies need to take cybersecurity and data protection seriously and give them top priority.

Several lawyers said that although many companies often talked about cybersecurity, few devoted sufficient resources to introducing stringent data protection measures. The back-to-back investigations of companies, including Didi, serve as a wake-up call that a new era of cybersecurity regulation is on the way, in tandem with the growing amount of data in people's work and daily lives.

Ma Jihua, a veteran independent technology analyst, said data security is not just about technology companies. It is also becoming increasingly relevant to companies in traditional sectors, as the real economy becomes intertwined with the digital economy, and as more industrial, manufacturing and medical data go online.

Toughened regulation of data security will also affect companies' core business models.

Ma said the challenges concerning data security, privacy, ownership and use pose a bigger question, as internet and technology companies rely heavily on monetization of data for revenue.

The Schall Law Firm, a US shareholder rights litigation firm, said in a statement that on behalf of Didi investors it is investigating claims of securities legislation violations. The investigation focuses on whether Didi issued false and/or misleading statements and/or failed to disclose information pertinent to investors.

Song, from Jincheng Tongda & Neal (Shanghai), said: "From now on, all companies need to evaluate their data assets to see whether they have such large volumes of data, or if their data concern national security. This is a prerequisite for companies to draft their development strategies."