Soccer fan groups across Germany plan to fall silent at games this weekend to protest the league's plan to sell a stake in TV and marketing income to an outside investor.

Fan clubs and groups known as “ultras” from many of Germany's largest clubs, including Bayern Munich and Borussia Dortmund, said on Friday they will fall silent for the first 12 minutes of their teams' upcoming games in a reference to the influence of fans as the proverbial 12th player of a soccer team.

“We are not prepared to stand idly by as German soccer gets sold out,” the groups said in a joint statement.

The protests made their mark on games in the top two divisions on Friday. Fans forced a five-minute stoppage by throwing chocolate coins wrapped in gold foil onto the field after keeping quiet for the first 12 minutes of Borussia Moenchengladbach's 2-2 draw with Werder Bremen. A second-division game was briefly halted after fans lit flares.

Supporters have been protesting with banners at Bundesliga games for months and fear an investor could pressure the league to change how the competition is run and focus more on TV viewers than the fans in the stadiums.

The fan groups say their “biggest weapon” is the way that the Bundesliga's marketing focuses heavily on Germany's packed stadiums and passionate crowds. Past protests played a key role in the league abolishing unpopular Monday evening kickoffs in what was widely seen as a victory over broadcasters.

The protests come after the top two men's soccer divisions voted narrowly to proceed on Monday with negotiations to allow an investment firm to acquire a percentage of future TV and marketing income in exchange for an up-front payment. The league says the share would be a maximum of 8 per cent over 20 years and that there are “several interested parties.”