monopolist

One who monopolizes or possesses a monopoly; one who has exclusive command or control of any branch of trade or article of commerce; specifically, a buyer up of the whole of a commodity in market for the purpose of selling at an advanced price; one having a license or privilege granted by authority for the sole buying or selling of any commodity. See monopoly.

One who obtains, assumes, or occupies anything to the exclusion of others: as, a monopolist of advantages.

One who monopolizes; one who has a monopoly; one who favors monopoly.

One who has, or attempts to acquire, a monopoly on something.

someone who monopolizes the means of producing or selling something