Formally, control is ensured by a package exceeding half of the voting shares: its owner can pass a decision made by simple majority, regardless of the position of others.
In practice, a smaller package is often sufficient. If the remaining shares are dispersed among many small shareholders, some of whom do not participate in meetings, actual control can be achieved with a stake significantly below half. Such control is called de facto control as opposed to de jure.
It is important to distinguish issues requiring a qualified majority: for these, a control package is insufficient, and the decision can be blocked by the owner of a sufficiently large stake.
For a minority investor, the presence of a controlling owner has a dual significance. On the one hand, it ensures strategic certainty and reduces the risk of corporate conflicts. On the other hand, decisions are made in the interests of the main owner, and the protection of minority rights is determined by legislative mechanisms rather than their votes.