Purchasing Power Parity and the Fisher Effect
International Parity Relationships and Forecasting Foreign Exchange Rates
Chapter Six
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
1
Chapter Outline
Interest Rate Parity
Covered Interest Arbitrage
IRP and Exchange Rate Determination
Currency Carry Trade
Reasons for Deviations from IRP
Purchasing Power Parity
PPP Deviations and the Real Exchange Rate
Evidence on Purchasing Power Parity
Fisher Effects
Forecasting Exchange Rates
Efficient Market Approach
Fundamental Approach
Technical Approach
Performance of the Forecasters
6-2
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
Law of one price (LOP)
Requirement that similar commodities or securities should be trading at the same or similar prices
Prevails when the same or equivalent things are trading at the same price across different locations or markets, precluding profitable arbitrage opportunities
Arbitrage equilibrium
Arbitrage is the act of simultaneously buying and selling the same or equivalent assets or commodities for the purpose of making certain, guaranteed profits
International Parity Relationships
6-3
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
Interest rate parity (IRP) is an arbitrage condition that must hold when international financial markets are in equilibrium
Manifestation of the LOP applied to international money market instruments and provides a linkage between interest rates in two different countries
Interest Rate Parity Defined
6-4
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
Suppose you have $1 to invest over a one-year period, and you will only consider default-free investments.
There are two alternative ways on investing your fund:
Invest domestically at the U.S. interest rate
If you choose this option, the maturity value in one year will be $1(1 + is), where is is the U.S. interest rate
Interest Rate Parity - Example
6-5
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
Suppose you have $1 to invest over a one-year period. There are two alternative ways on investing your fund:
Invest in a foreign country, say, the U.K., at the foreign interest rate and hedge the exchange risk by selling the maturity value of the foreign investment forward. This option requires the following steps:
Exchange $1 for a pound, that is, £(1/S) amount at the prevailing spot exchange rate (S)
Invest the pound amount at the U.K. interest rate (i£), with the maturity value of £(1/S)(1+i£)
Sell the maturity value of the U.K. investment forward in exchange for a predetermined dollar amount, that is, $[(1/S)(1+i£)]F, where F denotes the forward exchange rate
Interest Rate Parity – Example (Continued)
6-6
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
Interest Rate Parity: Equivalent Investments
Effective dollar interest rate from the U.K. investment alternative is given by:
U.S. and U.K. investment examples are equivalent
Future dollar proceeds from investing in the two equivalent investments must be the same, implying the following:
or
6-7
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
Arbitrage
IRP can be derived by constructing an arbitrage portfolio, which involves the following:
No net investment
No risk
No net cash flow generated in equilibrium
When IRP does not hold, the situation gives rise to covered interest arbitrage opportunities, allowing certain arbitrage profits to be made without the arbitrageur investing any money out of pocket or bearing any risk
6-8
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
IRP and Exchange Rate Determination
Reformulating the IRP relationship in terms of the spot exchange rate yields:
Forward exchange rate can be viewed as the expected future spot exchange rate conditional on all relevant information being available
Combining the two equations yields the following:
6-9
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
St+1 is the future spot rate when the forward contract matures
It denotes the set of information currently available
9
IRP and Exchange Rate Determination Continued
Two things are noteworthy from the following equation (presented on previous slide):
“Expectation” plays a key role in exchange rate determination (i.e., when people “expect” the exchange rate to go up in the future, it goes up now)
Exchange rate behavior will be driven by news events
6-10
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
10
Uncovered Interest Rate Parity
When the forward exchange rate F is replaced by the expected future spot exchange rate, E(St+1), we obtain:
Uncovered interest rate parity
Interest rate differential between a pair of countries is (approximately) equal to the expected rate of change in the exchange rate
6-11
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
E(e) is the expected rate of change in the exchange rate
11
Currency Carry Trade
Unlike IRP, the uncovered interest rate parity often does not hold, giving rise to uncovered interest arbitrage opportunities
Currency carry trade involves buying a high-yielding currency and funding it with a low-yielding currency, without any hedging
The carry trade is profitable if the interest rate differential is greater than the appreciation of the funding currency against the investment currency
6-12
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
Since the interest rate in Japan has been near zero since the mid-1990s, the yen has been the most popular funding currency for carry trade, followed by the Swiss franc.
12
EXHIBIT 6.3 Interest Rate Spreads and Exchange Rate Changes: Six-Month Carry Trade Periods for Australian Dollar–Japanese Yen Pair
6-13
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
Note: For interest rates, interbank six-month rates are used for both countries. The interest rate spread and the rate of change in the exchange rate are plotted at the beginning of each six-month carry period.
Source: Interest rates and exchange rates are obtained from Datastream.
13
Reasons for Deviations from IRP
IRP holds quite well, but it may not hold precisely all the time due to (primarily) two main reasons:
Transaction costs
Interest rate at which the arbitrager borrows tends to be higher than the rate at which he lends, reflecting the bid-ask spread
There exist bid-ask spreads in the foreign exchange market as well, as the arbitrager must buy currencies at the higher ask price and sell at the lower bid price
Capital controls
Governments sometimes restrict capital flows, inbound and/or outbound via jawboning, imposing taxes, or outright bans
6-14
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
EXHIBIT 6.4 Interest Rate Parity with Transaction Costs
6-15
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
EXHIBIT 6.5: Deviations from Interest Rate Parity: Japan, 1978-1981 (in percent)
6-16
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
Note: Daily data were used in computing the deviations. The zone bounded by +0.339 and −0.339 represents the average width of the band around the IRP for the sample period.
Source: Otani, I., and S. Tiwari. (1981). “Capital Controls and Interest Rate Parity: The Japanese Experience, 1978–81,” IMF Staff Papers 28: pp. 793−816.
16
Purchasing Power Parity
When the law of one price is applied international to a standard consumption basket, we obtain the theory of purchasing power parity (PPP)
PPP states the exchange rate between currencies of two countries should be equal to the ratio of the countries’ price levels of a commodity basket
Let P$ be the dollar price of the standard consumption basket in the U.S. and P£ the pound price of the same basket in the U.K.
Absolute version of PPP states the exchange rate between the dollar and pound should be:
6-17
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
S is the dollar price of one pound.
17
Purchasing Power Parity Continued
When the PPP relationship is presented in the “rate of change” form, instead of price level as in the absolute version of PPP, we obtain the relative version of PPP:
Where:
e is the rate of change in the exchange rate
π$ and π£ are the inflation rates in the United States and U.K., respectively
6-18
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
e is the rate of change in the exchange rate
π$ and π£ are the inflation rates in the United States and U.K., respectively
18
PPP Deviations and the Real Exchange Rate
If there are deviations from PPP, changes in nominal exchange rates cause changes in the real exchange rates, affecting the international competitive positions of countries
Real exchange rate, q, is found by:
If PPP holds, the real exchange rate will be unity (i.e., q = 1), but when PPP is violated, the real exchange rate will deviate from unity
6-19
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
19
Evidence on PPP
PPP has been the subject of a series of tests, yielding generally negative results, especially over short horizons
Generally unfavorable evidence about PPP suggests that substantial barriers to international commodity arbitrage exist
As long as there are nontradables (e.g., haircuts, housing, etc.), PPP will not hold in its absolute version
If PPP holds for tradables and the relative prices between tradables and nontradables are maintained, then PPP can hold in its relative version
6-20
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
20
Fisher Effects
The Fisher effect holds that an increase (decrease) in the expected inflation rate in a country will cause a proportionate increase (decrease) in the interest rate in the country
Formally, the Fisher effect is written as follows:
Fisher effect implies that the expected inflation rate is the different between the nominal and real interest rates in each country, that is,
6-21
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
ρ$ denotes the equilibrium expected “real” interest rate in the United States
21
Fisher Effects Continued
If we assume the real interest rate is the same between countries, that is, ρ$ = ρ£, we obtain the international Fisher effect (IFE), which suggests the nominal interest rate differential reflects the expected change in exchange rate
When the international Fisher effect is combined with IRP, we obtain the forward expectations parity (FEP), which states any forward premium or discount is equal to the expected change in the exchange rate
6-22
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
22
EXHIBIT 6.9: International Parity Relationships among Exchange Rates, Interest Rates, and Inflation Rates
6-23
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
Notes:
1. With the assumption of the same real interest rate, the Fisher effect (FE) implies that the interest rate differential is equal to the expected inflation rate differential.
2. If both purchasing power parity (PPP) and forward expectations parity (FEP) hold, then the forward exchange premium or discount will be equal to the expected inflation rate differential. The latter relationship is denoted by the forward-PPP, i.e., FPPP in the exhibit.
3. IFE stands for the international Fisher effect.
23
Forecasting Exchange Rates
Many business decisions are now made based on forecasts, implicit or explicit, of future exchange rates
Forecasting techniques can be classified into three distinct approaches:
Efficient market approach
Fundamental approach
Technical approach
6-24
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
24
Efficient Market Approach
Efficient market hypothesis (EMH) states that financial markets are informationally efficient in that the current asset prices reflect all the relevant and available information
Implies that the exchange rate will change only when the market receives new information
Random walk hypothesis suggests today’s exchange rate is the best predictor of tomorrow’s exchange rate
To the extent that interest rates are different between two countries, the forward exchange rate will be different from the current spot exchange rate
6-25
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
25
Fundamental Approach
Uses various models to forecast exchange rates
Three main difficulties of this approach:
One must forecast a set of independent variables to forecast the exchange rates, and forecasting the former will certainly be subject to errors and may not be necessarily easier than forecasting the latter
Parameter values that are estimated using historical data may change over time because of changes in government policies and/or the underlying structure of the economy
Model itself can be wrong
6-26
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
26
Technical Approach
First analyzes the past behavior of exchange rates for the purpose of identifying “patterns” and then projects them into the future to generate forecasts
Based on the premise that history repeats itself
At odds with the efficient market approach
Differs from fundamental approach in that it does not use the key economic variables, like money supplies or trade balances, for purpose of forecasting
Two examples of technical analysis:
Moving average crossover rule
Head-and-shoulders pattern
6-27
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
27
EXHIBIT 6.10: Moving Average Crossover Rule: Golden Cross vs. Death Cross
6-28
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
28
EXHIBIT 6.11: Head-and-Shoulders Pattern: A Reversal Signal
6-29
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
29
Performance of the Forecasters
Can professional forecasters outperform the market?
Eun and Sabherwal (2002) study found that banks as a whole could not outperform the random walk model, but some banks significantly outperformed the random walk model, especially in the longer run
Beckmann and Czudaj (2017) suggest professionals have a hard time predicting exchange rates, and uncertainty regarding economic policy and macroeconomic and financial conditions significantly affects professionals’ forecast errors
6-30
Copyright © 2021 by the McGraw-Hill Companies, Inc. All rights reserved.
30