The tech giant has already been handed €7 billion in fines in the European Union, but more could be on the way. The latest case relates to unfair practices with its AdSense program.
The European Union's anti-trust regulator plans to fine Google's parent company Alphabet with another fine for unfair competition practices, AFP and Reuters news agencies reported on Friday, citing unnamed sources.
The possible fine relates to a case currently running that targets the tech giant's AdSense advertising service. A verdict in the long-running case is expected in the coming weeks.
Google has already been fined €7 billion ($8 billion) in the EU for two offenses related to its Android operating system and its shopping platform.
The Financial Times, which also cited unnamed sources, claimed the European Commission could fine the group an additional $13 billion, but the expected penalty would likely be significantly less.
The Commission opened the AdSense case in 2016, accusing Google of preventing third parties that use its AdSense product from displaying advertisements from Google's competitors.
It said Google had kept its anti-competitive practices for a decade.
Further investigations against the company could also be on the horizon.
Meanwhile, the agency is reportedly considering a probe against Apple for using its app store to gain an advantage over rivals.