lecture 24: risk premium portfolio diversification risk.pdf · 24: risk premium & portfolio...

Download Lecture 24: Risk Premium Portfolio Diversification Risk.pdf · 24: Risk Premium & Portfolio Diversification

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  • Lectures 24 & 25: Risk

    Lecture 24: Risk Premium & Portfolio Diversification Bias in the forward exchange market

    as a predictor of the future spot exchange rate

    What makes an asset risky?

    The gains from international diversification

    The portfolio balance model

    Appendix: Intervention in the FX Market

    Lecture 25: Sovereign Risk

    Lecture 26 Possible topics: Procyclical fiscal policy

    Greece & the euro crisis

    Recent macro history of China ITF220 - Prof.J.Frankel

  • Does the Forward Market Offer an Unbiased Predictor of the Future Spot Exchange Rate?

    ITF220 - Prof.J.Frankel

    More particularly, does the forward discount equal the mathematically expected percentage change in the spot rate:

    (fd)t = Et st+1 ?

    Given Covered Interest Parity, it is the same as the question whether the interest differential is an unbiased predictor:

    (i-i*)t = Et st+1 ?

    So then, does the interest differential equal the math-ematically expected percentage change in the spot rate?

  • Is the interest differential an unbiased predictor of the future spot exchange rate?

    Usual finding: No. Bias is statistically significant: (i-i*)t Et st+1 . .

    In fact, Et st+1 is much closer to zero (a random walk).

    The bias supports the carry trade:

    One can make money, on average, going short in a low-i currency and long in a high-i currency.

    How can this be?

    One interpretation: Rational expectations fails, ste Etst+1

    Another: Uncovered interest parity fails, i-i*t ste

    ITF220 - Prof.J.Frankel

    A risk premium separates (i-i*)t from ste


    In this case, riskier currencies should be the ones to pay higher returns.

  • What makes an asset risky to a portfolio investor?

    If uncertainty regarding the value of the currency (variance) is high.

    If you already holds a lot of assets in that currency.

    If currency is highly correlated with other assets you hold. What matters is how much risk the currency adds to your overall portfolio.

    ITF220 - Prof.J.Frankel

  • The gains from international diversification

    James Tobin: The theory of optimal portfolio diversification

    Dont put all your eggs in one basket.

    The theory was worked out for stocks in the Capital Asset Pricing Model (CAPM).

    Applies to all assets: bonds, equities; domestic, foreign.

    International markets offer a particular opportunity for diversification, because they move independently to some extent.

    ITF220 - Prof.J.Frankel

  • What portfolio allocation minimizes risk?

    Assume 2 assets (e.g., domestic & foreign), each with probability of earning -1, of earning +1. Variance of overall portfolio Et (overall returnt+1)


    Assume the 2 assets are uncorrelated.

    If entire portfolio allocated to 1st asset, Variance = (-1)2 + (+1)2 = 1.

    If entire portfolio allocated to 2nd asset, Variance = (-1)2 + (+1)2 = 1.

    If portfolio is allocated half to 1st asset & half to 2nd, Variance = (-1)2 + ()(0)2 + (+1)2 = . Thats minimum-variance. Maximum diversification.

    ITF220 - Prof.J.Frankel

  • Diversification lowers risk to the overall portfolio.

    The investor can achieve a lower level of risk by diversifying internationally.

    Standard deviation of return to portfolio

    ITF220 - Prof.J.Frankel

  • Investors want to minimize risk and maximize expected return.

    To get them to hold assets that add risk to the portfolio, you have to offer them a higher expected return.

    That is why stocks pay a higher expected return than treasury bills.

    Do foreign assets pay a higher expected return than domestic assets?

    ITF220 - Prof.J.Frankel

  • Placing 20% of your portfolio abroad reduces risk (diversification). After that point, the motive for going abroad is higher expected return;

    investors who are more risk averse wont go much further.



    Medium risk- aversion

    High risk- aversion

    Low risk- aversion

    Purely US

    ITF220 - Prof.J.Frankel

  • Similarly, putting 25% of the global portfolio

    in emerging markets gives diversification.



    After that, the gain in expected return

    comes at the expense of higher risk.

    ITF220 - Prof.J.Frankel

  • The Portfolio Balance Model Portfolio investors should allocate shares in their portfolios to countries assets as: - a decreasing function of the assets risk, and - an increasing function of its expected rate of return (risk premium).

    Valuation effect in fx: a 1% increase in supply of $ assets (whether in the form of money or not) can be offset by a 1% depreciation, -- so that portfolio share is unchanged, and -- therefore no need to increase expected return to attract demand.

    Another implication: => FX intervention can have an effect even if sterilized.

    One implication: As its debt grows, a deficit country will eventually experience depreciation of its currency, or its interest rate will be forced up, or both.

    ITF220 - Prof.J.Frankel

  • APPENDIX: Intervention in the foreign exchange market

    was effective in 1985, to bring down the $, represented by the G-5 agreement at the Plaza Hotel;

    and was effective at times subsequently (though not always).

    Since 2001, the ECB, Fed, & BoJ have intervened very little;

    In 2013 the G-7 agreed not to intervene, to avoid currency wars.

    But other floaters intervene more often, Esp., major emerging market countries,

    ITF220 - Prof.J.Frankel

  • US FX intervention, even though sterilized, can sometimes be effective: The Plaza Accord of 1985 brought the dollar down,

    and the G-7 meeting of 1995 brought it up.


    ITF220 - Prof.J.Frankel

  • Managed float (leaning against the wind):

    Kaushik Basu & Aristomene Varoudakis, Policy RWP 6469, World Bank, 2013, How to Move the Exchange Rate If You Must: The Diverse Practice of Foreign Exchange Intervention by Central Banks and a Proposal for Doing it Better May, p. 14

    Turkeys central bank buys lira when it depreciates, and sells when it is appreciates.