Take a look at the rules in the link above, what is most worrying in these cases are possible influences to manipulate results
Imagine a scenario where 2 teams are owned by the same owner. Team A and team B, now imagine that a result for team A can directly affect team B, whether it's with qualification, a place in the round of 16, or even a direct confrontation
What should you do in this situation and how can you guarantee that the team's owner won't influence the result to benefit both teams?
These rules are important to sustain the integrity of UEFA competition. Without these rules, rich club owners can even feature more than one club which will increase their chances of winning these UEFA-organised competitions. These club owners will definitely influence the outcome of the games that include clubs they own. I read that these football regulatory organisations want to relax these rules. I am comfortable with these rules but UEFA can still look into these rules because there have been a wise of businesses that are investing in different clubs. Denying a club that has worked so hard to get to the Champions League the opportunity to compete because of its ownership will be a great disservice to the players and coaching crew.