HONG KONG — Some ambitious Chinese online media companies have won backing from a very powerful investor: the Chinese government itself.

Two small companies — a military news site called Tiexue and a news aggregator called Zaker — have recently offered stakes to affiliates of the Chinese government or the Communist Party, according to company documents and official media. The deals are part of a government drive to exercise oversight over media companies through special shares that grant their holders outsize influence over management and content.

The two firms are relatively small. And Chinese cyberspace regulators have been busy tightening controls in more forceful ways over the past few months ahead of an important Communist Party gathering set to begin next week.

But the deals struck with the two online news companies could be a sign of things to come. The news media in China is becoming more difficult to police as readers and outlets migrate online and onto social media. Experts said that if the deals work, the authorities could eventually ask for stakes at some of the country’s largest and most innovative companies in order to solidify influence over their services.