Suppose that Americans decide to increase their saving. a. If the elasticity of U.S. net capital

Suppose that Americans decide to increase their saving. a....

Key Concepts

Open Economy Saving?Investment Identity

In an open economy, the national saving identity expresses that a country’s total saving is divided between domestic investment and net capital outflow (or net exports). This identity links domestic economic decisions to international financial flows and trade balances, emphasizing how changes in private saving affect the allocation between domestic investment and foreign asset purchases.

Elasticity of Net Capital Outflow with Respect to the Real Interest Rate

This concept describes how sensitive the net capital outflow (the amount of domestic saving invested abroad minus foreign saving invested domestically) is to changes in the real interest rate. A high elasticity means that even small changes in the real interest rate bring about large shifts in net capital outflow, thereby limiting the impact of a change in private saving on domestic investment because a larger portion of the saving adjustment is absorbed by cross?border financial flows.

Elasticity of Exports with Respect to the Real Exchange Rate

This concept measures how responsive the volume of a country’s exports is to changes in the real exchange rate. When export elasticity is low (inelastic), a given change in the real exchange rate results in only a small change in export volumes. Therefore, in the context of an increase in private saving, a low export elasticity compels a larger adjustment in the real exchange rate (often a significant depreciation) to restore equilibrium in external markets.

Adjustment Mechanisms in International Financial Markets

This key concept involves understanding how shifts in saving behavior and capital flows interact with interest rates and exchange rates to maintain market equilibrium. In an open economy, changes in private saving influence domestic interest rates, which in turn affect net capital outflow and the real exchange rate. The sensitivity, or elasticity, of these relationships determines whether adjustments occur primarily through shifts in domestic investment, international capital flows, or exchange rate movements.

Transcript

00:02 Okay, question 9.

00:05 Suppose that americans decide to increase their saving.

00:10 So the first step of this question is we know that saving increase.

00:14 So this one shifts to the right.

00:20 So we know that in this question we must have a decrease in the real interest rate.

00:28 Okay, let's continue to answer sub -question a.

00:32 If the elastic is, if the elastic of us net capital outflow with respect to the real interest rate is very high.

00:41 Will this increase in private saving have a large or small effect on us domestic investment? so to answer this question, we have to know the concept of elasticity.

00:55 So elasticity in this question is how much a change of the real interest rate is going to affect the change in net capital outflow.

01:14 So the small triangle here in the front equals to the change, that is the greek letter delta, i think.

01:27 So we know that in this question, we have a large elasticity.

01:32 So this is a large number.

01:33 So that means that the denominator can be very small, while the numerator can be a large number.

01:41 That is why this whole term right here is large.

01:46 Okay, so let's continue to analyze this situation.

01:51 We know that the real interest rate goes down, right? so we must have this new equilibrium like accordingly, like in the bottom right of this original equilibrium, the original blue dot here.

02:06 So the new equilibrium is the red dot over here.

02:11 And another condition we know is that this ratio is huge.

02:17 So a small change in the real exchange rate, say a small change in the y -axis is going to have a huge effect on the x -axis.

02:30 I would just draw this more dramatically.

02:33 So actually this curve is like, like this is the eraser.

02:40 So this black curve here is actually very flat.

02:47 That is how we can have this high elasticity.

02:51 So if i redraw this graph, it is like something like this, right? with the blue dot being the old equilibrium and the red dot being the new equilibrium.

03:05 So a small change in the real exchange rate is going to have a huge impact on the net capital outflow.

03:12 So that is how we have this high elasticity in this question...

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