A Literature Review of the Efficiency of the Foreign Exchange Market
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Lecture 2
- Chapters 2 & 3
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Lecture 1 revision
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Floating versus Fixed Exchange rate
- Pure float: exchange rate at any moment determined by net demand for currency
- Fixed exchange rate: monetary authority intervenes by a) buying up excess supply of $ with £ (when £ strong, $ weak) or b) satisfying excess demand for $ by selling $ for £ (when £ weak, $ strong), so as to prevent excess demand /supply affecting rate
- a) adds $ to FX reserves, adds to £ in circulation
- b) takes $ out of FX reserves, reduces £ in circulation
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1.3 Balance of payments
1. Current account: export receipts as credits, import payments as debits, net = current account balance (goods, services including financial services, interest and dividends, rent, tourism)
2. Capital account: net capital inflows = net purchases of £ by foreigners in order to acquire claims on UK residents less net sales of £ by UK residents in order to acquire claims on foreigners (Long term including securities – equities, bonds etc - real estate etc + short term including bank deposits, short term securities)
Total net underlying demand for £ = 1 + 2 (basic balance) is equated to zero by exchange rate movement, unless Government intervenes to fix exchange rate, in which case:
3. Reserve change = - (1 + 2) to prevent basic balance causing exchange rate to move
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2.4 Purchasing Power Parity
(i = 1, . . ., N) (2.3)
where
- domestic prices of good number i;
- foreign prices of good number i.
(2.4)
where
- home country’s price index,
- foreign country’s price index.
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Chapter 3
Financial Markets in the Open Economy
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Introduction
- The exchange rate is key to international finance
- Allocation of wealth between assets within an economy is just a matter of risk and return
- But Internationally we have to also factor in the exchange rate
- The basic relationship is UIP
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3.1 Uncovered Interest Rate Parity
Figure 3.1 Uncovered interest rate parity
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3.1.3 Uncovered Interest Rate Parity
(3.1)
where
r - interest rate in the UK
r* - interest rate in the US
- ratio of the expected exchange rate at the end of the year
to the actual rate at the time of the decision
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3.1.3 UIRP: A Simplification
Redefine as follows:
(3.2)
where
- expected rate of depreciation of the domestic currency.
Rewriting (3.1) using (3.2),
(3.3)
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Unless the rate of currency depreciation is very high, the final term in (3.3) can be ignored, so:
(3.4)
which is the approximate form of the uncovered interest rate parity (UIRP) condition.
Interpretation: in equilibrium, domestic interest rate higher (lower) than the foreign interest rate by the expected rate of depreciation (appreciation) of the domestic currency, so as to compensate holders of the currency for their capital loss (gain) on the exchange rate.
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Risk and expectations
- UIRP involves expected rate of depreciation.
- If expectations wrong, payoff to depositors in FX greater or smaller than RHS in (3.4)
- If investors risk-neutral (indifferent to risk), they carry the risk of expectations error willingly, without requiring compensation
- If investors risk-averse (risk avoiders), they only carry the risk of expectations error if offered compensation – a risk premium added to payoff on RHS of (3.4)
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3.2 Covered Interest Rate Parity
Using the forward exchange rate F in place of
(3.5)
Defining f as the forward premium)
(3.8),
and ignoring the final term,
(3.9)
- the normal formulation of the CIRP hypothesis.
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Borrowing and lending
- To ensure CIP holds we do not need speculators with lots of assets
- If CIP does not hold it would be profitable to borrow in one currency and invest in another
- An investor who has a liability in a currency is short in that currency
- An investor who has an asset in a currency is long in that currency
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3.4 Covered interest rate parity – the facts
The gap between UK and US interest rates is less than
the transaction cost, c
(3.10)
Otherwise instantaneous arbitrage occurs.
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3.5 Efficient Markets – a first encounter
- Efficient market: prices fully reflect all available information, so no unexploited profit opportunities left
- Unbiased forward exchange rate equals spot rate expected when forward contract matures, so that:
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3.6 PPP revisited
When inflation expected, risk-neutral domestic depositors require payoff of r to give them real return (real interest rate), R:
Unless expected inflation rate very high, Rdp small, so:
which is the Fisher equation. (Note: r is observable, but dpe is not, so R = r - dpe is unobservable, though instead we often consider R = r – dp, where dp is the most recent inflation rate. The approximation works well if inflation is expected to remain at its current level)
(3.14)
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Ex-post Real Interest Rates
Using 12-month Lagged Inflation Rates* and 10-year Bond Yields
* Based on CPI, except for Australia (PPI)
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3.6.2 PPP and the real exchange rate
Fisher equation for the foreign country
(3.14’)
(3.14) and (3.14)’ imply:
(3.15)
With risk neutrality, the nominal interest rate differential is equal
to the expected rate of depreciation (UIRP), so
(3.16)
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In the absence of barriers to cross border capital movements
Therefore (3.17)
(PPP in expectations), which implies: (3.18)
or: (3.19)
i.e. real exchange rate expected to remain constant (next year’s real exchange rate expected to be same as this year’s) – random walk real exchange rate theory
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3.6.2 PPP and the real exchange rate (continued)
Suppose all economic agents know with absolute accuracy:
- the future price levels in the two countries
- next year’s exchange rate
(3.20)
Using UIRP,
(3.21)
or:
(3.22)
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UIRP, Fisher and PPP
- 3 parity relationships, but only 2 endogenous variables (“unknowns”): inflation differential, dp-dp*, and interest differential, r – r*, which are therefore overdetermined
- Any 2 parity relationships implies the 3rd:
PPP + UIRP Fisher
Fisher + UIRP PPP etc etc
- Reminder: this presupposes
- risk neutral investors,
- free movement of goods and capital
- no transaction costs
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Chapter 4
Open Economy Macroeconomics
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4.1 IS-LM model of aggregate demand
4.1.1 IS curve
The national income identity in an open economy:
(4.1)
where
Y (real) national income
C expenditure on consumption
I investment
B exports – imports = balance of payments current account
G Net government spending (budget deficit)
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Since saving is simply unspent income:
S = Y - C
(4.1) implies that:
S = Y – C = I + G + B
or: B = S – I – G
or: S - I- B = G (4.3)
So (current account of) balance of payments is simply saving net of investment or net national saving (saving of household sector less dissaving of corporate and government sectors)
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4.1.1 IS curve (continued)
A country’s current account is determined by the real exchange
rate:
where is the price of foreign (US) goods, measured in
pounds (domestic currency).
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4.1.1 IS curve (continued)
Now assume S=by, I=-zr and B=hQ
(4.4)
where b, z, h – behavioural parameters, all positive.
Setting
(4.5)
-relationship between y and r, for given values of G and Q.
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4.1.1 IS curve (continued)
Figure 4.1 The IS curve
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4.1.1 IS curve (continued)
From Figure 4.1
If and ,
(4.5a)
If and ,
(4.5b)
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4.1.2 Money Market
Relationship between the demand for money and national income
(ignoring the opportunity cost)
(4.6)
where
the demand for money
national income, both measured in nominal terms
k positive constant.
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4.1.2 Money Market (continued)
Define nominal national income Y as follows:
where y is real income and P is the price level.
Equation (4.6) is rewritten as follows:
(4.7)
- Cambridge quantity equation
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4.1.2 Money Market (continued)
Dividing both sides of Eq.(4.7) by P leads to
(4.8)
where
left-hand side – the demand for real money balances;
right-hand side – k times the real income generated in the economy.
Modifying Equation (4.8) to take account of the opportunity cost
of holding money:
(4.9)
where l is a positive constant and r is the interest rate.
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Government budget constraint
- G-T= the budget deficit
- This must be funded by borrowing or printing money
- G-T= change in money +change in gov debt
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4.1.2 Money Market: supply of money in an open economy
Balance sheet equation of FX= central Bank reserves LG=Lending to gov, MB=monetary base, MBb=currency plus deposits with central bank, L=loans, D=deposits
1. the central bank (MB):
2. the commercial banks (D):
Adding the two equations:
where is domestic credit (DC) which is total lending of the consolidated banking sector, both to the government and to the private, non-bank sector.
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4.1.2 Money Market (continued)
Figure 4.2 Balance sheet of the banking system
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4.1.2 Money market:
supply of money in an open economy
Using the definition of DC and subtracting
where
Since the money stock is the sum of the total of currency in circulation
and deposits in the banks, i.e.,
(4.10)
Rewrite equation (4.1) in terms of discrete changes:
(4.11)
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Exchange rates and Money
- A pure floating exchange rate official financing not used to manipulate the exchange rate. Money stock can be controlled by the government (maybe?)
- Fixed exchange rate, foreign reserves used to fix the exchange rate by affecting demand and supply, government looses control of the money supply
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4.1.2 Money market: LM curve
Equation (4.9) means
(4.12)
Given that
(4.13)
which has the same general form as the equation of the IS curve.
Given the LM curve, for the money market to clear,
if the interest is
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4.1.2 Money market: LM curve
Figure 4.3 the LM curve
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IS-LM
- We can now put the IS and LM curves together to produce a unique solution for y and r.
- And change in things such as G or money will change the equilibrium of the system
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Aggregate Demand
- We can now see how the solution to IS-LM would vary as the price level changes
- This gives the aggregate demand curve
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4.1.3 Aggregate demand
Figure 4.4 derivation of the aggregate demand curve
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Aggregate supply
- We have an aggregate demand curve, if we face this with an aggregate supply curve we can then derive the full solution to the system
- Two extreme assumptions
- Classical flexible prices
- Keynesian fixed prices
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Classical flexible prices
- Supply is determined by firms and the production function.
- Production is a function of Employment
- Employment is determined by the labour market which fixes the real wage to make demand and supply equal.
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Figure 4.5 derivation of the classical aggregate supply curve
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Keynesian fixed nominal wages
- The extreme Keynesian assumption is that wages will not respond.
- So as prices change the real wage changes and firms change their production levels
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Figure 4.6 derivation of the Keynesian aggregate supply curve
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A compromise case
- Stickey prices but which do adjust eventually
- Initially real things adjust as in the keynesian case but over time wages adjust and eventually we get to the classical case of no change in real things, only prices
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4.2.3 A compromise: sticky prices
Figure 4.7 the sticky price aggregate supply curve
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Conclusion
- We have seen the effects of interest rates on exchange rates (UIP) and efficient markets
- The IS-LM analysis with an open economy effect from the exchange rate on exports and imports
- The effect of exchange regimes on the money stock
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