Trust, in law, legal relationship in which property is administered by a trustee, who has some of the powers of an owner, for the benefit of a beneficiary; the trustee is obliged to act only in the beneficiary's best interest and can derive no advantage except an agreed upon fee. The trustee may be an individual, perhaps looking after the property of a child until it comes of age, or a corporate body; banks and trust corporations often act as trustees of larger properties. Under specialized form, called corporate trust, a group of trustees may hold the stock and thus control the operations of companies that would normally be competitors. The Sherman Antitrust Act (1890) attacked such trust, but enforcement was weakened by U.S. Supreme Court decisions. Enforcement of antitrust legislation has become complicated by the growth of huge conglomerates, which control many companies in different industries.