19.3 – How Government Borrowing Affects Investment and the Trade Balance
19.3 – How Government Borrowing Affects Investment and the Trade Balance
Learning Objectives
By the end of this section, you will be able to:
- Explain the national saving and investment identity in terms of demand and supply
- Evaluate the role of budget surpluses and trade surpluses in national saving and investment identity
When governments are borrowers in financial markets, there are three possible sources for the funds from a macroeconomic point of view: (1) households might save more; (2) private firms might borrow less; and (3) the additional funds for government borrowing might come from outside the country, from foreign financial investors. Let’s begin with a review of why one of these three options must occur, and then explore how interest rates and exchange rates adjust to these connections.
The National Saving and Investment Identity
The national saving and investment identity, which we first introduced in The International Trade and Capital Flows chapter, provides a framework for showing the relationships between the sources of demand and supply in financial capital markets. The identity begins with a statement that must always hold true: the quantity of financial capital supplied in the market must equal the quantity of financial capital demanded.
Recall that, orthodox economists hold that savings are ultimately loaned out, to businesses for investment, families for houses, and so forth. In this perspective, the U.S. economy has two main sources for financial capital: private savings from inside the U.S. economy and public savings.
[latex]\text{Total savings = Private savings (S) + Public savings (T - G)}[/latex]
Governments often spend more than they receive in taxes and, therefore, public savings (T – G) is negative. This causes a need to borrow money in the amount of (G – T) instead of adding to the nation’s savings. If this is the case, we can view governments as demanders of financial capital instead of suppliers. In algebraic terms, we can rewrite the national savings and investment identity like this:
Let’s call this equation 2. We must accompany a change in any part of the national saving and investment identity by offsetting changes in at least one other part of the equation because we assume that the equality of quantity supplied and quantity demanded always holds. If the government budget deficit changes, then either private saving or investment or the trade balance—or some combination of the three—must change as well. Figure 1 shows the possible effects.
What about Budget Surpluses and Trade Surpluses?
The national saving and investment identity must always hold true because, by definition, the quantity supplied and quantity demanded in the financial capital market must always be equal. However, the formula will look somewhat different if the government budget is in deficit rather than surplus or if the balance of trade is in surplus rather than deficit. For example, in 1999 and 2000, the U.S. government had budget surp