week 9 Flashcards
a) about exchange rate b) open economies more broadly
Nominal exchange rates vary over time,
WHY do nominal exchange rates vary as much as they do?
A big part of the answer is:
different rates of inflation
To explain this: theory of exchange rates
What is Purchasing Power Parity [PPP]?
☆ The first (long run) theory of exchange rates ☆
“a unit of any given currency should be able to buy the same quantity of goods in all countries”
Purchasing power parity means that so the real exchange rate E must be equal to ___?
1
The reason that 1 = eP/P* should hold is —?
Arbitrage
If real exchange rates differ:
Someone can buy in one country, sell in another + make a profit.
Such arbitrage would continue until equality (parity) in prices sets in
theory of PPP tells us that the nominal exchange rate between 2 countries…
— nominal exchange rate between 2 countries reflects the price levels in those countries.
This is clear since:
1 = eP/P*
1 = eP/P* if and only if — ?
e = P* / P
When relative prices change — MUST change!
When relative prices change e MUST change!
e.g. if domestic prices P rise faster than prices abroad P*
then e must decline and you get fewer dollars per pound
(Depreciation)
an increase in the money supply → increase in prices, so when a country increases its money supply faster than other countries…
its exchange rate should depreciate
2 classical exchange rate theories
- quantity theory of money→ explains how the money supply affects the price level
- purchasing power parity→ explains how price level affects nominal exchange rate
money, prices + nominal exchange rate during german hyperinflation
Notice how similarly these three variables move.
When the quantity of money started growing quickly, the price level followed, and the mark depreciated relative to the dollar.
When the German central bank stabilised the money supply, the price level and exchange rate stabilised as well.
limitations of PPP? [4]
- Doesn’t always happen in practice, especially in the short run.
- Real exchange rates are not constant over time
- many goods (services, like haircuts) are not easily traded
- even tradable goods are not always perfect substitutes(bmw vs toyota) → diff. characteristics
== transaction costs inhibit profitable arbitrage
Nonetheless, theory of PPP:
Is a good starting point for understanding currency movements in the long run
What PPP theory doesn’t do is …
say much about trade deficits or the currency market in the SR
Over the last many years, the UK + US have run persistent trade deficits.
why?
to answer: we introduce a model of how net exports, net capital outflow + the exchange rate are determined to relate to each other
open economy model assumptions
model assumptions
1) GDP taken as given
— **Real GDP** determined by supplies of the factors of production + technology that converts these inputs → outputs
2) economy’s price level is also taken as given
(a model of the short run)
An open economy model has 2 markets, which are:
- supply and demand for loanable funds
- supply and demand for foreign currency
what does supply and demand for loanable funds coordinate?
— coordinates a country’s saving, investment + NCO. now in an open economy
what does **supply and demand for foreign currency* coordinate?
— coordinates people who want to exchange the domestic currency for foreign currency
MODEL: how net exports, net capital outflow + the exchange rate are determined to relate to each other
The market for loanable funds. In an open economy, Savings =?
S = I + NCO
What does S = I + NCO mean?
- Saving = Domestic Investment + Net capital outflow
Saving can be used to finance domestic or foreign capital accumulation
- S is the supply of loanable funds (domestic savings)
- I + NCO is the demand for loanable funds
- asset demand may stem from investments at home (I) or abroad (NCO)
the real rate of interest r equilibrates the supply and demand for …?
loanable funds (precisely as in a closed economy).
The demand curve I(r)+NCO(r) is decreasing because …?
— A higher rate of interest discourages investments at home and makes foreign assets relatively less attractive hence discourages residents from buying foreign assets