If Bundesliga executives thought the tennis ball protests that have dominated the league for weeks would end after an investor deal collapsed, they suddenly had to think again.

Eintracht Frankfurt fans decided last weekend to send down a volley of tennis balls, plastic balls and a toy pig against Wolfsburg in a new protest against their opponents' being backed by car giant Volkswagen. The question now is whether match interruptions in German football will continue this weekend and in the future, as supporter groups flex their muscles, having claimed victory in the battle with the Bundesliga over an external investor.

The general feeling among fans is mixed, with many seemingly at odds with the Frankfurt action. But the risk of contagion is very real given simmering resentment against clubs who have exemptions from Germany's famed 50+1 rule.

"It is too tempting to do more protests for many fan scenes because the anti-investor protests worked," said Bernd Schmidt from the Mainz fan scene. "Wolfsburg and other clubs like them are easy targets and there have been protests against them before. Maybe tennis balls and match suspensions are now risky, but why not try to make the German game even purer?"

What were the original tennis ball protests?

Bundesliga fans protested for weeks and delayed many matches after the German Football League (DFL), which runs the Bundesliga, tried to find an external investor to help boost its international marketing.

The DFL went down this route because the 50+1 rule means most clubs are not allowed to be majority owned by one big investor. In order to try to catch up with the might of the English Premier League, a league-wide investor deal was needed — much like how LaLiga in Spain paired up with private equity firm CVC.

But tradition is important to German "ultra" fans and they were having none of it. Bundesliga commentators were suddenly wondering if they were covering football or tennis as greenish-yellow balls rained down from the stands. The Frankfurt-based DFL then announced that conditions had not been met and any investor deal was dead, for now.

Fans celebrated, with Union Berlin ultras taking particular glee by hanging a banner which read: "Game, set, match." Most observers thought the protests were over, so it was a big surprise when the tennis balls suddenly returned.

But in the words of the X (formerly Twitter) account of Eintracht fan SGEuropa.de, the targets of the protest were opponents Wolfsburg, who have an exemption to the 50+1 rule, having been set up by Volkswagen.

"Wolfsburg came, and THAT was perfect in terms of timing. Investors toppled, nobody expected a protest action and bang!" SGEuropa.de wrote. "We don't let anyone tell us WHEN to protest, we do it when it suits us! Greetings to VW."

Many fans of other clubs on social media are annoyed with Eintracht supporters for not taking part in the widespread protests against a DFL external investor.

"While in Frankfurt DFL officials are busy working on the investor deal, the local fan scene shows an absolute indifference to the topic," the Cologne ultra group Coloniacs said at the time.

But Frankfurt ultras have always seen themselves as separate to the collective and one of the more radical fan bases. Other reasons they did not participate in the investor protests were complex.

Their board member, Axel Hellmann, was a key proponent of the investor idea and had held talks with his own fans to assuage fears. Ultras were also on shaky ground with Frankfurt police after several spats — although the chances of league-wide sanctions from the football authorities against clubs for the investor protests always looked unlikely, given the PR risks.

Eintracht fans have also pointed out that when there were protests against Monday matches in the Bundesliga a few years ago, Eintracht supporters pioneered the idea of throwing tennis balls onto the pitch during matches to show their dissatisfaction. Again, the DFL caved and Monday games were dropped.

Could more protests follow?

The element of surprise was key to the protest against Wolfsburg and naturally the ultras do not want to confirm if they will launch similar protests against Bayer Leverkusen, Hoffenheim and RB Leipzig as part of a bid to try to end exemptions from 50+1.

Along with Wolfsburg — founded in 1945 by Volkswagen factory workers — Leverkusen is the other remaining exemption because big pharmaceutical company Bayer still owns the club, which was started by its own factory workers.

Leverkusen tend not to get so much flak from other fans given they have existed since 1904, although Stuttgart ultra group Commando Cannstatt 1997 told DW that they had previously protested when Leverkusen visited. They hung a banner in 2021 with a pharmaceutical pun: "Against risks and side effects, abolish exceptions — keep 50+1".

Hoffenheim used to have an exemption but owner Dietmar Hopp, the founder of the SAP software firm, transferred most of his voting rights back to the club last year. RB Leipzig, despite clearly being backed by energy drinks maker Red Bull, has a complicated ownership structure which gets around 50+1.

Fans away from Frankfurt seem skeptical on social media over the motives of Eintracht supporters, and doubt more protests will follow, either in Frankfurt or elsewhere.

But a leading Frankfurt ultra, who did not want to be named, told DW: "Twitter is not the real world, but we can't say how other scenes will handle things."

Werder Bremen fan scene member @JackXLetten wrote on X: "Protests against Wolfsburg are important and justified at any time."

Schalke fan @S04_Julian06 added: "Protesting against Wolfsburg is just as valid as protesting against Hoffenheim and Red Bull."

Having got rid of Monday games and the investor plans, German soccer fans can never be underestimated. Whether they can force the likes of Wolfsburg to change their business models remains to be seen.

Editing by: James Thorogood