Applications of state space models in finance
Applications of state space models in finance
Applications of state space models in finance
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7.1 Factor model<strong>in</strong>g 127<br />
predictability <strong>of</strong> <strong>in</strong>ternational equity returns (Ferson and Harvey 1993) the authors add<br />
a dollar and an oil price factor. Jones and Kaul (1996) explicitly document the impact <strong>of</strong><br />
changes <strong>in</strong> the oil price on the stock market. In another application, Chan et al. (1998)<br />
use the growth rate <strong>of</strong> monthly <strong>in</strong>dustrial production, the default premium, the real<br />
<strong>in</strong>terest rate def<strong>in</strong>ed as the difference between the return on one-month Treasury-bills<br />
and the relative change <strong>in</strong> the monthly consumer price <strong>in</strong>flation, the slope <strong>of</strong> the yield<br />
curve, the change <strong>in</strong> the monthly expected <strong>in</strong>flation and the maturity premium, def<strong>in</strong>ed<br />
as return difference between long-term government bonds and the one-month Treasurybill<br />
rate, as macroeconomic variables. The authors conclude that only the default and<br />
the maturity premium are significantly related to stock returns. In a work on maximized<br />
predictability <strong>in</strong> stock and bond markets <strong>in</strong> the US, Lo and MacK<strong>in</strong>lay (1997) rely on<br />
the dividend yield, the default spread, the maturity spread, the return on the S&P 500<br />
and an <strong>in</strong>terest-rate trend, calculated as the change <strong>of</strong> average yields on a long-term<br />
government bond. More recently, Lettau and Ludvigson (2001) successfully employ the<br />
log consumption-wealth ratio as a condition<strong>in</strong>g factor.<br />
7.1.1.2 Fundamental factors<br />
The second category <strong>of</strong> factors is related to firm-specific attributes. Various empirical<br />
studies have illustrated that it is possible to earn risk-adjusted returns by construct<strong>in</strong>g<br />
portfolios <strong>in</strong> accordance with fundamental factors. Basu (1977) f<strong>in</strong>ds the PE effect: firms<br />
with low PEs have higher sample returns and firms with high PEs have lower sample<br />
returns than can be expected <strong>in</strong> the context <strong>of</strong> a mean-variance efficient market portfolio.<br />
Banz (1981) documents the size effect with higher than expected returns for firms with a<br />
small market capitalization. Bhandari (1988) documents a positive relationship between<br />
average returns and leverage. Rosenberg et al. (1985) report the so-called value premium,<br />
where the average returns are positively related to the book-to-market equity ratio, which<br />
is def<strong>in</strong>ed as a company’s book value (BV) to its market value (MV). At the beg<strong>in</strong>n<strong>in</strong>g<br />
<strong>of</strong> the 1990s, Chan et al. (1991) confirms the value premium also for Japanese equities.<br />
Subsequent studies, see, for example, Fama and French (1993, 1995, 1998), Lakonishok<br />
et al. (1994) and Daniel and Titman (1997), gave further confirmation <strong>of</strong> the bookto-market<br />
anomaly and tried to f<strong>in</strong>d different explanations for the value premium. In<br />
today’s portfolio management <strong>in</strong>dustry, the most important <strong>in</strong>vestment style is based on<br />
the value premium: a value <strong>in</strong>vestor <strong>in</strong>vests <strong>in</strong> firms with the highest book-to-market<br />
ratios, which means <strong>in</strong>vest<strong>in</strong>g <strong>in</strong> the relatively cheapest value companies.<br />
Fama and French (1992, 1996) developed a more comprehensive framework. Instead <strong>of</strong><br />
conduct<strong>in</strong>g <strong>in</strong>dividual analyses for the various anomalies, they take the <strong>in</strong>terdependencies<br />
between the different variables explicitly <strong>in</strong>to account. They analyze the empirical<br />
relationships between the expected return <strong>of</strong> a stock, its beta and other fundamentals<br />
such as size, book-to-market equity, leverage and earn<strong>in</strong>gs-price ratios. Their work<br />
is considered a milestone as they <strong>in</strong>terpret the comb<strong>in</strong>ation <strong>of</strong> different variables as<br />
a multidimensional measure for risk. The most widely used fundamental multifactor<br />
model, which dom<strong>in</strong>ates today’s empirical research, is the three-factor model by Fama<br />
and French (1993). It expla<strong>in</strong>s the cross-section <strong>of</strong> expected returns by three factors: a<br />
market proxy, size and the book-to-market ratio. Even though a solid economic theory