The German Football League (DFL) wants to tighten rules to ensure investors do not take full control of more clubs.
The existing ’50+1′ rule blocks investors from controlling a majority of voting rights in clubs.
It means supporters have a say in how their clubs are run, rather than one outside influence or investor.
However some clubs are excused so the DFL has submitted a proposal to ensure no future exemptions are granted while tightening the current framework.
Wolfsburg, Hoffenheim and Bayer Leverkusen are the clubs exempt from the 50+1 rule.
Leverkusen and Wolfsburg are excused because their investors have had an interest in the clubs for more than 20 years.
Hoffenheim are spared from the rule because of major investor Dietmar Hopp’s substantial financial commitment to their grassroots activities as well as his funding of professional and amateur football in Germany.
The DFL said those clubs would continue playing in the top leagues but would have to meet some criteria to retain their status.
Hopp said last week Hoffenheim would not require exemption in the future as he would be handing back the majority of his voting rights to the club without any compensation.
The purpose of the 50+1 rule is to ensure fans feel part of their clubs, which were historically not-for-profit organisations run by member associations in Germany.
Under current rules clubs cannot compete in the Bundesliga if commercial investors have more than a 49% stake – in contrast to other European leagues where clubs can change hands and be taken over by other investors.
