Trade

Trade (commerce) is the process by which goods and services are exchanged between two willing parties. Exchange can take the form of money or barter (goods for goods). The fundamental reason trade occurs is that each party values what it receives more highly than what it gives.

Trade takes place at different levels: local markets, within a country, and across borders. It depends on a monetary system, transport, price information, and law to enforce contracts. When any of these are absent, business costs rise.

Economic foundations

The principle of comparative advantage holds that two parties can both benefit from trade even if one produces everything more efficiently than the other. What matters is not who is most efficient, but the opportunity cost of choosing to produce one thing instead of another. This drives specialization: each location produces what it can make at the lowest cost.

International trade

Trade across borders depends on government policy. Common tools include tariffs (customs duties), quotas (limits on quantity imported), and health and quality standards. Governments use tariffs to raise revenue, protect domestic industry, or pursue political goals. Bilateral and regional trade agreements can reduce these barriers.

Patterns and culture

Historically, trade routes carried far more than goods: languages, technical knowledge, religion, and disease. The Indian Ocean and Red Sea long connected the coasts of East Africa, Arabia, and India, with seasonal monsoon winds setting the timing of voyages. Merchants built networks based on trust and custom, which substituted for international law.