A closed economy is a theoretical economic model in which a country conducts no international trade or financial transactions with the rest of the world — all production is consumed domestically, all savings are invested internally, and there are no imports, exports, or cross-border capital flows. In a closed economy, national income equals domestic consumption plus domestic investment plus government spending (Y = C + I + G). While no economy in the modern world is truly closed, the concept is used in macroeconomic analysis as a baseline model before introducing the open economy effects of trade, capital flows, and exchange rates. For students of economics and investors on Ventura Securities, understanding the closed economy framework is foundational to grasping how international trade and FII/FDI flows modify economic equilibria in India's open economy context.