HONG KONG, BEIJING: China’s market regulator on Saturday blocked the merger of Tencent-backed game streaming platforms Douyu and Huya after an antimonopoly investigation as authorities step up scrutiny of some of the country’s largest tech companies.

Huya and Douyu – which provide live video game streaming services similar to Twitch in the US – are two of the largest companies of their kind in China. Both have the gambling company Tencent among their investors.

China’s state administration for market regulation said in a statement that a merger between Huya and Douyu would give Tencent control of the merged company.

“From the perspective of various key indicators such as sales, number of active users, resources for streamers, the total share is very high and the elimination and restriction of competition is foreseeable,” the statement said.

Authorities have stepped up oversight of some of China’s largest tech companies over concerns about monopoly behavior and unbridled growth, and the way companies collect and use data from their millions of users.

Also on Saturday, China’s cyber regulator released draft measures requiring companies with the personal data of over one million users to apply for cybersecurity permits if they plan to be listed overseas. The Cyberspace Administration of China said in a statement that the review and approval was required because of the risk that the data could be “influenced, controlled and maliciously exploited by foreign governments.”

There is also a risk that important data could be used illegally or transferred abroad.

Last week, the cyber regulator ordered a cybersecurity investigation into the ride-sharing platform Didi Global Inc. Meituan food delivery platform is also the subject of an anti-monopoly investigation, and e-commerce giant Alibaba was fined a record $ 2.8 billion earlier this year for antitrust violations.

China’s market regulator said the decision to ban the merger between Huya and Douyu marks the first time regulators have outlawed market concentration in the internet sector.

The two companies first announced last October that they were planning a merger, but market regulators later said they would review the $ 6 billion deal.

Tencent said it was informed by the regulator that the merger has been halted.

“The company will adhere to the decision, comply with all regulatory requirements, act in accordance with applicable laws and regulations and meet our social responsibility,” the company said in a statement on Saturday.

Earlier this week, the Chinese authorities announced that they would also strengthen supervision of companies listed abroad.

The new measures will improve the regulation of data security and the cross-border flow of data as well as the handling of confidential data.

The authorities also plan to crack down on illegal activity in the securities market and will investigate and punish acts such as the fraudulent issuance of securities, market manipulation and insider trading.

Meanwhile, the Cyberspace Administration of China ordered the removal of 25 Didi Global Inc. apps from the app stores. Didi is the largest ride hailing service in the country.

Behind the move, the agency cited serious violations of the rules against the collection of personal data.

The Cyberspace Administration of China had already shut down the main Didi app last Sunday in anticipation of a cybersecurity review after it debuted on the US stock exchange last week.

The 25 additional apps include Didi Enterprises as well as apps developed for Didi drivers.

A spokesman for Didi did not immediately respond to a request for comment.