Fans of the German second division club Union Berlin are planning a 15-minute silence at the start of their home game against RB Leipzig on Friday to protest against their big-spending opponents, who are backed by the energy drink maker Red Bull.

RB Leipzig are owned by the Austrian drinks company and have invested heavily in the team’s playing squad for several seasons as they climbed the divisions, with the Bundesliga now firmly in their sights.

Leipzig have moved up from the fifth tier in 2009 to the second tier last year, winning promotion three times in five seasons. They also made more headlines this season after signing the talented German youth international, the 20-year-old Davie Selke from Werder Bremen, by luring him to the second division with a multi-million Euro contract.

Under German football rules they cannot be called Red Bull Leipzig and are officially known as RasenBallsport Leipzig (grassball sport Leipzig) or RB Leipzig.

“Leipzig has again spent vast amounts of money on new players, almost all of whom had offers from the top division,” wrote the Union fan group Scene Koepenick in an open letter to the Berlin club’s fans. “The financial possibilities seem endless.“

“But we will fight for the preservation of football culture for as long as possible. Pure marketing instruments like RasenBallsport will never be part of that culture and that is why we call on a 15-minute silence.”

Union Berlin, located in the eastern part of the capital, could not be more different to Leipzig having held a reputation as being an anti-establishment club since the days of East Germany, and feature fierce fan loyalty.

A club official said Union was fully behind the fan initiative: “I can only use the words of our president Dirk Zingler who fully backs this initiative by 100% ,” club spokesman Christian Arbeit said. “RB Leipzig can expect more protests.”

Union Berlin has close ties to its fans with hundreds of them helping rebuild their stadium a few years ago and organise blood donations to save the club. It also gave fans in 2011 the chance to own part of the stadium, by issuing 10,000 shares at €500.

In February they extended the contract of their veteran player Benjamin Köhler by a year after he was diagnosed with cancer.

RB Leipzig are one of four clubs worldwide controlled by the drinks maker. The others are in Salzburg, New York and in Brazil.