Anti-trust are those set of laws which punish successful businesses (or trusts) for being successful, i.e., dominant. To quote philosopher Ayn Rand writing in “Antitrust: The Rule of Unreason” Voice of Reason,
The alleged purpose of the Antitrust laws was to protect competition; that purpose was based on the socialistic fallacy that a free, unregulated market will inevitably lead to the establishment of coercive monopolies. But, in fact, no coercive monopoly has ever been or ever can be established by means of free trade on a free market. Every coercive monopoly was created by government intervention into the economy: by special privileges, such as franchises or subsidies, which closed the entry of competitors into a given field, by legislative action…The Antitrust laws were the classic example of a moral inversion prevalent in the history: an example of the victims, the businessmen, taking the blame for the evils caused by government, and the government using its own guilt as a justification for acquiring wider powers, on the pretext of “correcting” the evils.