Google shares closed down 1.6% today on multiple reports that the European Union is about to charge it with antitrust law violations following a five-year investigation. Fines could exceed $6 billion.

EU Competition Commissioner Margrethe Vestager decided to go after the search giant, rejecting a company effort to negotiate a settlement, according to reports in the  Financial Times and The Wall Street Journal.

Officials believe Google’s Android  forced mobile phone manufacturers to favor its apps including YouTube. In addition, they may claim that the company muscles publishers into using its search ads, and blocks advertisers from using other search services.

Vestager is expected to disclose her specific charges tomorrow, first in Brussles and then in the U.S., It could become “one of the defining antitrust cases of the Internet era,” the FT says.

In addition to the expected EU battle, the French senate is expected to endorse legislation that would empower telecom regulators to examine Google’s search algorithms to determine whether they’re fair.