How does Domestic Saving and Investment Determine the Trade Balance?

One insight from the national saving and investment identity is that a nation's own levels of domestic saving and investment determine a nation’s balance of trade. To understand this point, rearrange the identity to put the balance of trade all by itself on one side of the equation. Consider first the situation with a trade deficit, and then the situation with a trade surplus.

In the case of a trade deficit, the national saving and investment identity can be rewritten as:

Trade deficit = Domestic investment – Private domestic saving – Government (or public) savings (M – X) = I – S – (T – G)

In this case, domestic investment is higher than domestic saving, including both private and government saving. The only way that domestic investment can exceed domestic saving is if capital is flowing into a country from abroad. After all, that extra financial capital for investment has to come from someplace.

Now consider a trade surplus from the standpoint of the national saving and investment identity:

Trade surplus = Private domestic saving + Public saving – Domestic investment (X – M) = S + (T – G) – I

In this case, domestic savings (both private and public) is higher than domestic investment. That extra financial capital will be invested abroad.

This connection of domestic saving and investment to the trade balance explains why economists view the balance of trade as a fundamentally macroeconomic phenomenon. As the national saving and investment identity shows, the performance of certain sectors of an economy, like cars or steel, do not determine the trade balance. Further, whether the nation’s trade laws and regulations encourage free trade or protectionism also does not determine the trade balance.

Related Topics

• Trade Balance: Surplus and Deficit
• Mercantilism
• J Curve
• National Trade Data Bank
• Capital Account (Economics)
• Merchandise Trade Balance
• Current Account 
• Income Payments
• Unilateral Transfer
• Is it better to have a trade surplus or a trade deficit? 
• Export of Goods and Services and Percentage of GDP
• Heckscher-Ohlin Model 
• Linder Hypothesis
• The Balance of Trade as a Balance of Payments
• National Savings and Investment Identity
• Circular Flow of Money
• Financial Capital
• Supply and Demand Sides for Financial Capital? 
• Flow of Capital
• Domestic Saving and Investment Determine the Trade Balance
• National Savings Identity and Trade Deficits
• How the Business Cycle Affects Trade Balances
• Trade Balance or Trade Surplus
• Level of Trade
• Comparative Advantage
• Absolute Advantage
• Specialization and Gain from Trade
• Absolute Advantage in All Goods
• Production Possibilities Frontier and Comparative Advantage
• Comparative Advantage and Mutually Beneficial Trade
• Gain from Trade
• Opportunity Costs and International Trade
• Intra-Industry Trade
• Splitting Up the Value Chain
• How Economies of Scale Lead to Trading Advantages
• Protectionism
• Closed Economy
• Tariffs 
• Double Column Tariff
• Import Quotas
• Double Column Tariff
• Infant Industry Theory
• National Interest Argument
• Race to the Bottom
• Anti-Dumping Laws
• Dumping
• Trade War
• Race to the Bottom
• Non-Tariff Barriers
• Effects of Trade Barriers
• Who Is Benefited and Who is Harmed by Protectionism?
• Infant Industry Theory for Restricting Imports
• What is the Anti-Dumping Argument for Restricting Imports?

• Anti-Dumping Laws
• Dumping

• What is the Environmental Protection Argument for Restricting Imports?
• Race to the Bottom
• Unsafe Consumer Products Argument for Restricting Imports?
• National Interest Argument for Restricting Imports
• What is the WTO?
• What is the GATT?
• What are Free Trade Agreements?
• North American Free Trade Agreement
• Central European Free Trade Agreement
• General Agreement on Free Tariff and Trade (GATT)
• Common Market
• Common Market for Eastern and Southern Africa
• Central American Common Market
• Caribbean Community and Common Market
• What are Economic Unions?
• WTO
• International Monetary Fund
• World Economic Forum
• Inter-American Development Bank
• Davos World Economic Forum 
• Chamber of Commerce
• Jackson Hole Economic Symposium