They are one of the few clubs who don't adhere to the 50+1 rule.
Their example might not be as extreme as RB because Bayer as a club were founded before the rule, and as a company have held shares in the club for a very long time (I guess since it's inception) rather than buying over a few clubs and starting new. They were actually started as a workers club of the Bayer company and have one of the oldest ultra groups in Germany, still active since the 80's I believe.
Leverkusen and Wolfsburg (Volkswagen) have an exception written into the 50+1 rule to allow them to continue on in their current set up.
Their backers can pretty much write-off any debts they have. Regardless of how successful their player trading model is I believe they were able to write-off ~£15m debts after covid and carry on as normal which others see as an unfair advantage.
Football in Germany is popular for many reasons: top-quality play, the highest average attendances in world football, low ticket prices and a great fan culture. A major contributing factor in this is the 50+1 ownership rule. bundesliga.com takes a closer look at exactly how and why it works...
www.bundesliga.com