Restraints of trade of various types are unlawful according to COMMON LAW and under state and federal ANTITRUST LAWs. In common law, covenants not to compete given by employees to employers and sellers of businesses to buyers are the most commonly contested restraints of trade. The law on covenants not to compete varies substantially from state to state, although courts generally are more willing to enforce sellers’ promises not to compete than those of employees whose livelihoods may be at stake upon termination of EMPLOYMENT. Restraints of trade are prohibited under most state antitrust laws and the federal SHERMAN ANTITRUST ACT. Courts have interpreted these prohibitions over many years to cover PRICE FIXING and market-division agreements among competitors, resale price maintenance and market division rules in distribution CONTRACTs, “tying arrangements” (the coerced purchase of unwanted goods or SERVICES), group BOYCOTTs (collective refusals to deal), exclusive dealing contracts, and other trade-restrictive business agreements and practices. Broadly speaking, only “unreasonable” restraints of trade are illegal. Many of the types of restraints of trade noted above have been deemed unreasonable.