Glass Shoes

Author
Affiliation

Hirotaka Fukui

Kobe University, Graduate School of Economics

Modified

February 23, 2026

It’s past 12 o’clock and I have to go back I’ll leave my heart as I leave, so let’s promise to meet In our future Glass Shoes - fromis_9

Modern Portfolio Theory

Expected Return of a Single Asset

Consider an asset \(i\) with \(J\) possible outcomes \(j = 1, \dots J\). Let \(R_{ij}\) denote the return for outcome \(j\) and \(p_{ij}\) denote its probability. The expected return is

\[ \mathbb{E}[R_{i}] = \sum_{j=1}^{J} p_{ij} R_{ij} \tag{1}\]

The variance of an asset \(i\) is

\[ \sigma^{2}_{i} = \sum_{j=1}^{J} p_{ij} \left(R_{ij}-\mathbb{E}[R_{i}] \right)^{2} \]

Portfolio with two risky assets

A portfolio consists with two risky assets indexed by \(i=A, B\). Let \(X_{i}\) be portfolio weights (\(X_{A}+X_{B}=1\)). The portfolio return is

\[ R_{p, m} = X_{A} R_{A, m}+ (1-X_{A}) R_{B, m} \]

The expected return of the portfolio is

\[ \mathbb{E}[R_{p}] = X_{A} \mathbb{E}[R_{A}]+ (1-X_{A}) \mathbb{E}[R_{B}] \]

The variance of the portfolio return is

\[ \begin{align} \sigma_{p}^{2} & = \left(X_{A} \sigma_{A}+ (1-X_{A}) \sigma_{B} \right)^{2} \\ & = X^{2}_{A} \sigma^{2}_{A} + (1-X_{A})^{2} \sigma^{2}_{B} + 2 X_{A} (1-X_{A}) \sigma_{AB} \end{align} \]

where \(\sigma_{12}\) is the covariance between asset A and asset B.

\[ \sigma_{12} = \sum_{j=1}^{J} p_{j} \left(R_{A, m}-\mathbb{E}[R_{A}] \right)\left(R_{B, m}-\mathbb{E}[R_{B}] \right) \]

Portfolio with \(N\) risky assets

Portfolio Possibility Curve

Minimum Risk Portfolio

Efficient Frontier

Riskless Lending and Borrowing

Single Index Model

Multi Index Model

Capital Asset Pricing Model (CAPM)

Arbitrage Pricing Theory (APT)

Empirical Tests of CAPM and APT

Consumption CAPM (C-CAPM)

Empirical Tests of C-CAPM

The Factor Zoo

Intermediary Asset Pricing

Production-based Asset Pricing

Demand System Approach to Asset Pricing

Important

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