European antitrust regulators are mulling another sizable fine against Google over its Android operating system and are seeking a second opinion from a panel of experts, Reuters reports. If the outside panel agrees with the regulators' conclusions, the European Commission could be on its way to issuing a decision against Google by the end of the year.

It's expected to top the record $2.7 billion (2.4 billion euro) fine the commission slapped Google with last month for allegedly favoring its own shopping service over rivals.

Why it matters: The money — albeit a lot of money — isn't that big a deal for Google. The fact that the EU is aggressively taking action over its dominance in multiple areas spells trouble ahead for dominant U.S.-based tech platforms that do significant business in Europe. In addition, the commission (which is also investigating Google's AdSense platform) has paved the way for companies who claim to be hurt by the search giant to bring cases against it.

The backstory: Last April, the EC charged Google with using its dominant Android mobile operating system to disadvantage competitors. The commission accused Google of requiring smartphone manufacturers to pre-install its search engine and browser, for example.The move came after complaints by advocacy group FairSearch, U.S.-based ad-blocking firm Disconnect, Portuguese app store Aptoide and Russian search engine Yandex.