By Wall Street Journal Staff

An executive at Tencent Holdings Ltd., China's most valuable publicly listed company, has been held by Chinese authorities, part of a probe into a high-profile corruption case involving one of the country's former top law-enforcement officials, people familiar with the matter said.

Zhang Feng has been under investigation by China's antigraft inspector since early last year for alleged unauthorized sharing of personal data collected by Tencent's social-media app WeChat, the people said. They said Mr. Zhang was suspected of turning over WeChat data to former Vice Public Security Minister Sun Lijun, who is being investigating by Beijing for undisclosed violations of Communist Party rules.

Investigators are looking at what type of data Mr. Zhang allegedly might have shared with Mr. Sun and what Mr. Sun might have done with it, the people said.

Hong Kong-listed Tencent, which has a market capitalization of about $900 billion, confirmed Thursday that Mr. Zhang is under investigation. The case "relates to allegations of personal corruption and has no relation to WeChat or Weixin," a spokesman said in a statement to The Wall Street Journal. Weixin is WeChat's sister app for the Chinese market.

Mr. Zhang was referred to as a Tencent vice president in a statement released by the municipal government of Zhangjiakou, a city near Beijing, in which he was described as having met the city's mayor in October 2018.

Tencent said Mr. Zhang has never held a senior executive position in the company or a managerial post.

It couldn't be determined where Mr. Zhang is now. He couldn't be reached for comment. Mr. Sun didn't respond to a request for comment sent through China's antigraft inspectors -- the Central Commission for Discipline Inspection -- and the State Council Information Office.

Mr. Zhang's case highlights how China's biggest technology companies can become tangled in political battles at the highest echelons of China's Communist Party. Companies such as Tencent have access to coveted data, as well as insight into the users that provide them. Beijing's concerns have been growing that technology companies could misuse that data or share it inappropriately, even as authorities at times demand access to it for their own purposes.

Anticorruption inspectors have been tight-lipped about Mr. Sun's alleged offenses, saying in April that he is suspected of breaking the law. He is one of the highest-profile security officials investigated since Chinese leader Xi Jinping launched a wide-ranging anticorruption campaign against law-enforcement authorities last year.

Authorities haven't confirmed that Mr. Zhang is under investigation.

As the probe into Mr. Zhang unfolds, Pony Ma, Tencent's billionaire founder and chief executive, hasn't been seen publicly in mainland China or in person at major public events. He has been spending most of his time in Hong Kong, the people familiar with the matter said.

Mr. Ma hasn't been accused of any wrongdoing. He didn't respond to requests for comment. China's State Council Information Office and the Central Commission for Discipline Inspection didn't respond to requests for comment.

Mr. Zhang joined Tencent in 2018, according to people familiar with the matter. Born in 1968, he spent most of his career in a Communist Party Central Committee department overseeing appointments of top party officials, according to stock-market filings from a Shenzhen-listed state-run company where he worked before moving to Tencent.

As Tencent's executive responsible for government affairs, Mr. Zhang met with Chinese government officials and was responsible for handling the company's relationship with ministries in Beijing, according to one of the people.

Tencent's mobile app WeChat is the predominant social-media platform in China. Its chat and online-payment functions make it an indispensable part of daily life for hundreds of millions of Chinese people.

Over the years, Tencent has collected a trove of data through its processing of the chat conversations and financial transactions of its 1.2 billion monthly active users, most of them in China. That has made WeChat a powerful surveillance tool for the Chinese government, which regulates Tencent and regularly has it suppress dissenting views on WeChat, the Journal has reported.

More recently, however, Chinese authorities have grown increasingly concerned that Tencent and other tech giants' data-collection systems give them unique insight into and power over Chinese society, challenging the Communist Party's desire to monopolize such information. In recent weeks, China has released new antitrust rules targeting internet platforms, which analysts say is motivated in part by Beijing's attempt to retake control of users' personal data.

Mr. Ma's lack of public appearances -- coming on the heels of China's recent crackdown against another billionaire entrepreneur, Jack Ma, who isn't related to Pony Ma -- triggered concern among current and former Tencent employees over why the company's founder hasn't been seen at events.

The last publicly documented in-person sighting in mainland China of Mr. Ma, who also goes by his Chinese name, Ma Huateng, was in August 2019 in Shanghai at the World Artificial Intelligence Conference.

Mr. Ma made only virtual appearances in Tencent's companywide year-end gatherings since December 2019 -- a break from his usual practice of attending such events in person. Employees have been told Mr. Ma is recovering from a back injury. Mr. Ma, a representative of the National People's Congress, was absent from last year's legislative proceedings in May, citing health reasons.

While in-person gatherings largely resumed in mainland China in mid-2020, Mr. Ma missed an October ceremony marking the 40th anniversary of China's first special economic zone in Shenzhen, where Tencent is based.

Meanwhile, Mr. Ma, 49 years old, has participated -- at least by audio -- in quarterly earnings calls. In November, he delivered a speech by audio at a philanthropic event.

Mr. Ma's lower-than-usual profile has had little impact on the operation of Tencent, whose revenue and stock price hit all-time highs during the pandemic as homebound users flocked to its videogames and digital services.

Tencent is now China's most valuable publicly traded company, having surpassed the e-commerce giant Alibaba Group Holding Ltd. in market cap most recently in December.

(END) Dow Jones Newswires

02-10-21 2302ET