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Lecture Covered Interest Rate Parity
Learning Objectives
Examine how Covered Interest Rate Parity (CIRP) contributes to exchange rate determination
Be able to examine CIPR conditions empirically
without and with transaction costs
Illustrate how arbitrage opportunities
may exist and be exploited
Reading: Madura and Fox, Ch 7
A spot exchange rate, S
quoted for immediate delivery of the purchased currency, or
the currency is delivered “on the spot” (usually within two working days).
A forward exchange rate, F
The rate agreed today for delivery of the currency at a future date.
Typically the future date is 30, 90, 180 days and one year ahead.
A currency forward contract , is an agreement between two parties to exchange currencies at pre-specified price (ie, a forward exchange rate) that will be settled in a future date (i.e. to lock in an exchange rate for a period of time.)
Spot and Forward Exchange Rates
The Rationale of CIP
Say that the spot and forward, exchange rates between the euro and the
dollar are given by and respectively and that the one-month
interest rates on an annual basis are r€ (rh )and r$ respectively.
Suppose now that that you are a French investor and you have two
investment choices:
α) deposits in € and
b) deposits in $.
For the second option you can use the forward exchange rate for eliminating
exchange rate risk
The Rationale of CIP
Explain what your expectations, actions, and trades/exchanges will be today
and in one month from today
Note: We can use the following “time line” to keep track of the above.
Today (t=0)
+1 month (t=1)
The Rationale of CIP
1st choice: Deposit in €
Deposit € A Receive € (1+ r€ )A
Total flows: €(1+ r€ )A
2nd choice: Deposit in $
Convert € A into $ A/S€/$
Deposit $ A/S €/$ Receive $ (1+ r$ )A/S €/$
Agreement to sell Forward Receive €(1+ r$ )A/S €/$ * F €/$
in one month to convert $ back to € (with certainty in one month)
Total flows: €(1+ r$ )A/S €/$ * F €/$
Today (t=0)
+1 month (t=1)
The Rationale of CIP
The two investments must have the same future value (in other words, the investor will be indifferent between the two). That is
€(1+ r€ )A = € (1+ r$ )A /S €/$ * F €/$
Otherwise arbitrage exists.
After some manipulation the above gives
(1+ r€ )= (1+ r$ ) * F €/$ /S €/$
Re-arranging
F €/$ /S €/$ = (1+ r€ ) / (1+ r$ )
Covered Interest Rate Parity
Define F0,1 the forward exchange rate
-- contracted now and to be delivered in the next period (e.g., in 30 days);
Define S0 the currently prevailing spot exchange rate;
rh is the interest rate in the home country, and;
rf is the interest rate in the foreign country during the period
The following relationship (parity)
between the spot exchange rate, forward exchange rate, and the interest rates in the two countries must hold
to eliminate any arbitrage opportunities:
(1)
Covered Interest Rate Parity
We deduct 1 from both sides of Eq (1)
And obtain:
(2)
Covered Interest Rate Parity
Therefore, CIRP states
The forward premium equals
the difference between the two interest rates over the period 0 - 1.
CIRP is sometimes approximated as:
(3)
11
Covered Interest Rate Parity
If this does not hold then
There are opportunities for profit
Might represent diagrammatically
Graphic Illustration of CIP
rh – rf
Remain investing in home currency
Convert to foreign currency/enter into forward contract, invest in foreign currency, convert back with forward
No difference
X
Y
f – s > rh – rf
Covered Interest Rate Parity Examples
Examine the following exchange rate and interest rate figures
Note: given a direct quotation, $ is the home currency
| The $/€ spot rate | S0 = 1.1237 |
| One year $/€ forward rate | F0,360 = 1.1128 |
| US discount rate (home country) | 2.50% pa |
| Euroland discount rate | 3.75% pa |
Covered Interest Rate Parity Examples
Questions
Part 1:
--- Do arbitrage opportunities exist?
Part 2:
--- If so, how would you invest to exploit the arbitrage
opportunities?
Covered Interest Rate Parity Examples
Answer to part 1:
The forward premium
The interest rate differential (exact) (rh - rf)/(1 + rf) = -0.01205
Conclusion:
As forward premium interest rate differential, arbitrage opportunities exist
As forward premium > interest rate differential, it would be more profitable to invest in €.
Covered Interest Rate Parity Examples
Answer to part 2:
1. If you have $1,000,000, convert it to €:
$1,000,000 / $1.1237/€ = €889917.2;
2. Enter into a forward contract to sell €, size decided below (€923289.1)
3. Invest in € for one year: €889917.2 (1+0.0375)=€923289.1
4. Convert € to $ with forward: €923289.1$1.1128/€ = $1,027,436
Note that
If you invest in $ for one year: $1,000,000(1+0.025) = $1,025,000
The arbitrage profit is $1,027,436 - $1,025,000 = $2,436
- If you have €1,000,000, you remain investing in €
Exercise
Suppose the investor does not use his own funds and borrows $1,000,000 at the interest rate of 2.0% (r$ ), how does he exploit the arbitrage opportunities?
S0 = $1.1237/ €, F0,360 = $1.1128/ €, r€ = 3.75% pa
Hint:
Step1: Borrow $1,000,000, convert it to € at $1.1237/€
Step 2: Enter into a forward contract to sell € at F = $1.1128/ €,
Step 3: Invest in € for one year
Step 4: Convert € to $ with forward at $1.1128/ €
Step 5: Repay the lender (principle + interest):
Calculate the arbitrage profit
Covered Interest Rate Parity and Arbitrage
Can interest rate parity be restored as a result of the above
transactions? Yes
The dollar interest rate will rise, the euro interest rate will fall.
As funds are withdrawn from $ and placed in € accounts
The spot exchange rate (dollars per euro) will rise and the forward rate will fall. These adjustments will continue until interest rate parity is restored.
Covered Interest Rate Parity; Transaction Costs and Arbitrage
Covered interest arbitrage involves transaction costs
Transaction costs reduce arbitrage opportunities
or prevent arbitrage opportunities from materialising.
These transaction costs include:
Bid-ask spreads in exchange rates
In the case of using borrowed funds,
Different lending and borrowing rates
CIRP; Transaction Costs and Arbitrage
Example
In the previous case,
In the US
if the loan rate is 3.00% pa
and the deposit rate is 2.00% pa,
and a zero bid-ask spread is still assumed for exchange rates,
Is it possible to make arbitrage profit using borrowed funds?
The future value of your $ borrowing in one year
$1,000,000(1+0.03) = $1,030,000
This figure is > $1,027,436 obtained from your activity of investing in €
So, you will not profit following this procedure
Though, you will get a higher return from investing in € if you have $ funds of your own
Covered Interest Rate Parity in Practice
Does covered interest rate parity hold?
Prior to 2007, documented violations of interest rate parity were very rare
Frequency, size and duration of apparent arbitrage opportunities do increase with market volatility
Why Deviations from Interest Rate Parity May Seem to Exist
Too good to be true?
Default risks – risk that one of the counterparties may fail to honor its contract
Exchange controls
Limitations
Taxes
Political risk
A crisis in a country could cause its government to restrict any exchange of the local currency for other currencies.
Investors may also perceive a higher default risk on foreign investments.
Why is the € interest rate for your assignment that for Germany and not Greece?
22
Covered Interest Parity Deviations During the Financial Crisis
Have seen that we might expect returns to be the same
Irrespective of where funds are invested
We can examine this using Covered Interest Rate Parity
Using forward contracts
Should not be possible to make arbitrage profits
Have seen how deviations from CIRP
Result in a movement of funds
So that the markets move back towards balance
Next time
Uncovered interest rate parity
Conclusion
Business School
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